Monday, November 28, 2011

Donor-specific anti-HLA Abs and graft failure in matched unrelated donor hematopoietic stem cell transplantation:
Anti-HLA donor-specific Abs (DSAs) have been reported to be associated with graft failure in mismatched hematopoietic stem cell transplantation; however, their role in the development of graft failure in matched unrelated donor (MUD) transplantation remains unclear. We hypothesize that DSAs against a mismatched HLA-DPB1 locus is associated with graft failure in this setting. The presence of anti-HLA Abs before transplantation was determined prospectively in 592 MUD transplantation recipients using mixed-screen beads in a solid-phase fluorescent assay. DSA identification was performed using single-Ag beads containing the corresponding donor's HLA-mismatched Ags. Anti-HLA Abs were detected in 116 patients (19.6%), including 20 patients (3.4%) with anti-DPB1 Abs. Overall, graft failure occurred in 19 of 592 patients (3.2%), including 16 of 584 (2.7%) patients without anti-HLA Abs compared with 3 of 8 (37.5%) patients with DSA (P = .0014). In multivariate analysis, DSAs were the only factor highly associated with graft failure (P = .0001; odds ratio = 21.3). Anti-HLA allosensitization was higher overall in women than in men (30.8% vs 12.1%; P < .0001) and higher in women with 1 (P = .008) and 2 or more pregnancies (P = .0003) than in men. We conclude that the presence of anti-DPB1 DSAs is associated with graft failure in MUD hematopoietic stem cell transplantation (read more)
Definitions of histocompatibility typing terms: Harmonization of Histocompatibility Typing Terms Working Group
Human Immunology Volume 72, Issue 12, December 2011, Pages 1214-1216 (Free access)
Histocompatibility testing for stem cell and solid organ transplantation has become increasingly complex as newly discovered human leukocyte antigen (HLA) alleles are described. HLA typing assignments reported by laboratories are used by physicians and donor registries for matching donors and recipients. To communicate effectively, a common language for histocompatibility terms should be established. In early 2010, representatives from clinical, registry, and histocompatibility organizations joined together as the Harmonization of Histocompatibility Typing Terms Working Group to define a consensual language for laboratories, physicians and registries to communicate histocompatibility typing information. The Working Group defined terms for HLA typing resolution, HLA matching and a format for reporting HLA assignments. In addition, definitions of verification typing and extended typing were addressed. The original draft of the Definitions of Histocompatibility Typing Terms was disseminated to colleagues from each organization to gain feedback and create a collaborative document. Commentary gathered during this 90-day review period were discussed and implemented for preparation of this report. Histocompatibility testing continues to evolve thus, the definitions agreed upon today, likely will require refinement and perhaps additional terminology in the future (read more).

Saturday, November 26, 2011

Toll-like receptor 4 engagement contributes to expression of NKG2D ligands by renal tubular epithelial cells:
Background. Engagement of Toll-like receptor (TLR) 4 on intrinsic kidney cells is critical for the full development of renal ischaemia–reperfusion injury (IRI). Effects of TLR signalling in renal parenchymal cells include the production of cytokines, chemokines and other soluble mediators which contribute to local inflammation and leucocyte accumulation. Whether engagement of TLR4 on kidney cells results in additional pro-inflammatory modifications of the renal microenvironment remains to be determined.
Methods. Renal IRI was induced by clamping of the renal pedicles, and expression of NKG2D ligands in mice deficient in TLR4 or its adaptor molecule MyD88, or else pretreated with blocking antibodies against the endogenous TLR4 ligand HMGB1, was compared to that in wild-type mice. Cultures of isolated renal tubular epithelial cells (TECs) from WT, TLR4–/– and MyD88–/– mice were stimulated with the TLR4 ligand lipopolysaccharide (LPS), or mineral oil occlusion was used to simulate IRI in vitro, prior to determination of NKG2D ligand expression. Chimeric mice lacking TLR4 in either the bone marrow derived or the parenchymal compartment were also subjected to IRI.
Results. In this study, we demonstrate a substantial increase in the expression of the NKG2D ligands retinoic acid early inducible-1 (RAE-1), murine ULBP-like transcript 1 (MULT-1) and histocompatibility-60 (H-60) in mouse kidneys during renal IRI. Expression of NKG2D ligands was attenuated in mice deficient in either TLR4 or the adaptor molecule MyD88. Antibody blockade of HMGB1 reduced NKG2D ligand expression by a comparable extent to TLR4 deficiency and did not result in further reduction of NKG2D ligand expression in TLR4–/– mice. Isolated TECs from normal mice but not those with defects in the TLR4–MyD88 signalling pathway expressed RAE-1 and MULT-1 upon exposure to LPS and after being subjected to in vitro conditions resembling ischaemia–reperfusion. TLR4 competence in the parenchymal but not the bone marrow-derived compartment was required for RAE-1 up-regulation in mouse kidneys after ischaemia, while TLR4 signalling in both compartments contributed to the intrarenal expression of MULT-1 during IRI.
Conclusion. Expression of the NKG2D ligands RAE-1 and MULT-1 on kidney cells in response to TLR4 engagement by HMGB1 represents another mechanism by which TLR4 signalling may participate in the pathogenesis of renal IRI (read more)

Friday, November 25, 2011

Desensitization With Antigen-Specific Immunoadsorption Interferes With Complement in ABO-Incompatible Kidney Transplantation.:
Transplantation. 2011 Nov 22;
Authors: Biglarnia AR, Nilsson B, Nilsson Ekdahl K, Tufveson G, Nilsson T, Larsson E, Wadström J
BACKGROUND.: Complement activation was characterized during and after desensitization treatment in 19 consecutive patients receiving ABO-incompatible (ABOi) living donor kidney transplants to assess the effect of desensitization protocol including antigen-specific immunoadsorption (IA) on complement activation. METHODS.: All patients received rituximab- and tacrolimus-based triple treatment. Anti-A/B antibodies were removed by IA. Serial determinations of C3, C3a, the C3a/C3 ratio, and sC5b-9 were carried out between day -30 and postoperative day 30. C1q was measured on day -30 and the day before the transplantation. In two recipients, eluates from immunoadsorbent columns were analyzed for C3a, C1q, and immunoglobulins by western blotting. Same complement analysis was performed in eluate from a control column after in vitro perfusion of AB-plasma. RESULTS.: Patient and graft survival were 100% for a median follow-up of 40 months (range, 12-60 months). There were no humoral rejections based on ABO-antigen-antibody interactions. C3a and the C3a/C3 ratio declined with the start of IA treatment, and this decline was maintained postoperatively. C1q declined from day -30 to a lower value on the day before transplantation (P<0.05). In eluates from both patient and control, immunoadsorbent column immunoglobulins together with C3a and C1q were detected. CONCLUSIONS.: The current protocol including antigen-specific IA interferes with the complement system; this effect may be partially responsible for the absence of humoral rejection resulting from ABO-antigen-antibody interactions and the excellent outcomes obtained after ABO-incompatible kidney transplantation (read more).

Wednesday, November 23, 2011

Natural Helper Cells Derive from Lymphoid Progenitors
Natural helper (NH) cells are recently discovered innate immune cells that confer protective type 2 immunity during helminth infection and mediate influenza-induced airway hypersensitivity. Little is known about the ontogeny of NH cells. We report in this study that NH cells derive from bone marrow lymphoid progenitors. Using RAG-1Cre/ROSA26YFP mice, we show that most NH cells are marked with a history of RAG-1 expression, implying lymphoid developmental origin. The development of NH cells depends on the cytokine receptor Flt3, which is required for the efficient generation of bone marrow lymphoid progenitors. Finally, we demonstrate that lymphoid progenitors, but not myeloid–erythroid progenitors, give rise to NH cells in vivo. This work therefore expands the lymphocyte family, currently comprising T, B, and NK cells, to include NH cells as another type of innate lymphocyte that derives from bone marrow lymphoid progenitors.

Monday, November 21, 2011

Tissue Antigens. 2010 Dec;76(6):459-66

Evaluation of computational methods for the reconstruction of HLA haplotypes.

Castelli ECMendes-Junior CTVeiga-Castelli LCPereira NFPetzl-Erler MLDonadi EA.


Departamento de Clínica Médica, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto-SP, Brazil.


Human leukocyte antigen (HLA) haplotypes are frequently evaluated for population history inferences and association studies. However, the available typing techniques for the main HLA loci usually do not allow the determination of the allele phase and the constitution of a haplotype, which may be obtained by a very time-consuming and expensive family-based segregation study. Without the family-based study, computational inference by probabilistic models is necessary to obtain haplotypes. Several authors have used the expectation-maximization (EM) algorithm to determine HLA haplotypes, but high levels of erroneous inferences are expected because of the genetic distance among the main HLA loci and the presence of several recombination hotspots. In order to evaluate the efficiency of computational inference methods, 763 unrelated individuals stratified into three different datasets had their haplotypes manually defined in a family-based study of HLA-A, -B, -DRB1 and -DQB1 segregation, and these haplotypes were compared with the data obtained by the following three methods: the Expectation-Maximization (EM) and Excoffier-Laval-Balding (ELB) algorithms using the arlequin 3.11 software, and the PHASE method. When comparing the methods, we observed that all algorithms showed a poor performance for haplotype reconstruction with distant loci, estimating incorrect haplotypes for 38%-57% of the samples considering all algorithms and datasets. We suggest that computational haplotype inferences involving low-resolution HLA-A, HLA-B, HLA-DRB1 and HLA-DQB1 haplotypes should be considered with caution.

Saturday, November 19, 2011

Download HLA Fusion 2.0 SP3 client update (service pack updates must be installed serially).
Proliferating Cell Nuclear Antigen Is a Novel Inhibitory Ligand for the Natural Cytotoxicity Receptor NKp44

NK cells play an important role in the early immune response to cancer. The NKp44 activating receptor is the only natural cytotoxicity receptor that is expressed exclusively by primate NK cells, yet its cellular ligands remain largely unknown. Proliferating cell nuclear Ag (PCNA) is overexpressed in cancer cells. In this study, we show that the NKp44 receptor recognizes PCNA. Their interaction inhibits NK cell function through NKp44/ITIM. The physical interaction of NKp44 and PCNA is enabled by recruitment of target cell PCNA to the NK immunological synapse. We demonstrate that PCNA promotes cancer survival by immune evasion through inhibition of NKp44-mediated NK cell attack.

Friday, November 18, 2011

Some useful transplant calculators found on the web (including mobile apps!).
You are welcome to suggest new ones !

Charlson comorbidity index (CCI)
intraoperative/postoperative myocardial infarction and cardiac arrest (MICA) risk calculator

Hematopoietic stem cell transplantation :
Liver transplantation :
Kidney transplantation :
Pancreas transplantation :
Lung transplantation :
Cytogam® dosing calculator

Thursday, November 17, 2011

Anti-A/B antibody depletion by semiselective versus ABO blood group-specific immunoadsorption.:

Nephrol Dial Transplant. 2011 Nov 15;

BACKGROUND: Recipient desensitization using blood group (BG)-specific immunoadsorption (ABO-IA) has proven to enable successful kidney transplantation across major ABO barriers. In this context, the efficiency of non-antigen-specific (semiselective) IA adsorbers has not yet been established. The objective of our study was to quantify anti-A/B antibody depletion by protein A-, peptide ligand- and anti-human immunoglobulin-based semiselective IA in comparison to ABO-IA.METHODS: Eight ABO-IA-treated transplant candidates and 39 patients subjected to semiselective IA for a variety of different indications outside the context of ABO-incompatible transplantation were included. Antibody patterns (IgG, IgG1-4 subclasses, IgM, C4d-fixing reactivities) were analysed applying conventional agglutination testing and flow cytometry.RESULTS: As assessed by sensitive flow cytometric antibody detection, ABO-IA-based desensitization led to a profound even though often incomplete reduction of anti-A/B reactivities. Persistent complement- or non-complement-fixing reactivities, however, were not associated with transplant rejection or capillary C4d deposition. Single sessions of semiselective IA turned out to be more effective than ABO-IA in decreasing levels of anti-A/B IgG [median reduction to 28 versus 59% (ABO-IA) of baseline values, P < 0.001). In contrast, BG-specific IgM (74 versus 30%, P < 0.001) and IgG3 (72 versus 42%, P < 0.05) were reduced to a lesser extent, without differences between tested adsorber types. Analysis of four consecutive IA sessions revealed that inferior efficiency could not be overcome by serial treatment.CONCLUSION: Our observation of limited adsorption capacities regarding distinct BG-specific Ig (sub)classes suggests caution in applying semiselective IA techniques in ABO-incompatible kidney transplantation.

Wednesday, November 16, 2011

IMGT/HLA Database | EBI:

Release 3.6.0, 10 October 2011

The IMGT/HLA Database provides a specialist database for sequences of the human major histocompatibility complex (HLA) and includes the official sequences for the WHO Nomenclature Committee For Factors of the HLA System. The IMGT/HLA Database is part of the international ImMunoGeneTics project (IMGT).

    Can G-CSF Cause Leukemia in Hematopoietic Stem Cell Donors?: A large majority of allogeneic hematopoietic stem cell donations are achieved using granulocyte-colony stimulating factor (G-CSF). G-CSF use has been associated with later development of myelodysplastic syndromes/acute myelogenous leukemia (MDS/AML) in several clinical circumstances. Although clinical data to date have failed to identify any increased incidence of MDS/AML in G-CSF mobilized donors, the quality of these data are insufficient to exclude a long-term risk. Physicians should explain the potential risk to donors, and where appropriate, offer donors the option of marrow donation.

    Tuesday, November 15, 2011

    Understanding the Causes of Kidney Transplant Failure: The Dominant Role of Antibody-Mediated Rejection and Nonadherence:
    We prospectively studied kidney transplants that progressed to failure after a biopsy for clinical indications, aiming to assign a cause to every failure. We followed 315 allograft recipients who underwent indication biopsies at 6 days to 32 years posttransplant. Sixty kidneys progressed to failure in the follow-up period (median 31.4 months). Failure was rare after T-cell–mediated rejection and acute kidney injury and common after antibody-mediated rejection or glomerulonephritis. We developed rules for using biopsy diagnoses, HLA antibody and clinical data to explain each failure. Excluding four with missing information, 56 failures were attributed to four causes: rejection 36 (64%), glomerulonephritis 10 (18%), polyoma virus nephropathy 4 (7%) and intercurrent events 6 (11%). Every rejection loss had evidence of antibody-mediated rejection by the time of failure. Among rejection losses, 17 of 36 (47%) had been independently identified as nonadherent by attending clinicians. Nonadherence was more frequent in patients who progressed to failure (32%) versus those who survived (3%). Pure T-cell–mediated rejection, acute kidney injury, drug toxicity and unexplained progressive fibrosis were not causes of loss. This prospective cohort indicates that many actual failures after indication biopsies manifest phenotypic features of antibody-mediated or mixed rejection and also underscores the major role of nonadherence.

    Friday, November 11, 2011

    HLA-targeted flow cytometric sorting of blood cells allows separation of pure and viable microchimeric cell populations

    HLA-targeted flow cytometric sorting of blood cells allows separation of pure and viable microchimeric cell populations:

    Microchimerism is defined by the presence of low levels of nonhost cells in a person. We developed a reliable method for separating viable microchimeric cells from the host environment. For flow cytometric cell sorting, HLA antigens were targeted with human monoclonal HLA antibodies (mAbs). Optimal separation of microchimeric cells (present at a proportion as low as 0.01% in artificial mixtures) was obtained with 2 different HLA mAbs, one targeting the chimeric cells and the other the background cells. To verify purity of separated cell populations, flow-sorted fractions of 1000 cells were processed for DNA analysis by HLA-allele–specific and Y-chromosome–directed real-time quantitative PCR assays. After sorting, PCR signals of chimeric DNA markers in the positive fractions were significantly enhanced compared with those in the presort samples, and they were similar to those in 100% chimeric control samples. Next, we demonstrate applicability of HLA-targeted FACS sorting after pregnancy by separating chimeric maternal cells from child umbilical cord mononuclear cells. Targeting allelic differences with anti-HLA mAbs with FACS sorting allows maximal enrichment of viable microchimeric cells from a background cell population. The current methodology enables reliable microchimeric cell detection and separation in clinical specimens.

    Thursday, November 10, 2011

    A Novel Pathway of Chronic Allograft Rejection Mediated by NK Cells and Alloantibody

    A Novel Pathway of Chronic Allograft Rejection Mediated by NK Cells and Alloantibody:

    Chronic allograft vasculopathy (CAV) in murine heart allografts can be elicited by adoptive transfer of donor specific antibody (DSA) to class I MHC antigens and is independent of complement. Here we address the mechanism by which DSA causes CAV. B6.RAG1−/− or B6.RAG1−/−C3−/− (H-2b) mice received B10.BR (H-2k) heart allografts and repeated doses of IgG2a, IgG1 or F(ab’)2 fragments of IgG2a DSA (anti-H-2k). Intact DSA regularly elicited markedly stenotic CAV in recipients over 28 days. In contrast, depletion of NK cells with anti-NK1.1 reduced significantly DSA-induced CAV, as judged morphometrically. Recipients genetically deficient in mature NK cells (γ-chain knock out) also showed decreased severity of DSA-induced CAV. Direct NK reactivity to the graft was not necessary. F(ab’)2 DSA fragments, even at doses twofold higher than intact DSA, were inactive. Graft microvascular endothelial cells responded to DSA in vivo by increased expression of phospho-extracellular signal-regulated kinase (pERK), a response not elicited by F(ab’)2 DSA. We conclude that antibody mediates CAV through NK cells, by an Fc dependent manner. This new pathway adds to the possible mechanisms of chronic rejection and may relate to the recently described C4d-negative chronic antibody-mediated rejection in humans.

    Wednesday, November 9, 2011

    Antibody Removal Before ABO-Incompatible Renal Transplantation: How Much Plasma Exchange Is Therapeutic?

    Antibody Removal Before ABO-Incompatible Renal Transplantation: How Much Plasma Exchange Is Therapeutic?: Background. ABOi transplantation is an accepted method of expanding the kidney donor pool but there is little analysis of the protocols used. We established an ABOi programme utilising leukocyte depletion, tacrolimus, TPE and IvIg. There are few reports in the literature on the success rates of antibody removal protocols or relating to patients in whom antibody removal fails. The purpose of this study was to define the likelihood of achieving transplantation depending on ABO antibody titers.
    Methods. 56 patients entered our ABOi program. Data were analysed to determine the likelihood of achieving transplantation, ABO antibody titre prior to antibody removal and amount of TPE required to achieve transplantation. The median antibody titer was 1:64 (Range 0–1:1024). Transplantation proceeded when the ABO titer reached ≤1:4.
    Results. 51/56 (91%) patients achieved transplantation after 8.3±5 TPE. Five patients with high ABO titers were not transplanted despite extensive TPE. The number of TPE required to reach an ABO titer of ≤1:4 correlates best with pre-treatment IgG titers.
    Conclusions. This is the first study to demonstrate a cut off titer for entry in to the ABO incompatible program using the relationship between ABO titer and amount of TPE required to reach transplantation. We now tailor the antibody removal protocol prior to transplantation and have introduced a cut-off entry titer to the program (≤1:256), because of the unacceptable risk of exposing patients with higher titers to long-lasting immunosuppression and costly, prolonged, courses of TPE without the guarantee of successful transplantation. Patients whose ABO titer exceeds the cut-off are counselled and offered alternative routes to transplantation.

    Tuesday, November 8, 2011

    Two years and 4 months: A long-term bridge to transplantation with a total artificial heart: We report our experience with a 38-year-old man with refractory end-stage biventricular heart failure due to an idiopathic dilative cardiomyopathy, who received a SynCardia temporary total artificial heart (SynCardia Systems, Inc., Tucson, AZ) as treatment. This procedure performed at our institution is the longest term bridge to heart transplantation (HTx) so far.

    Conversion to low transfusion-related acute lung injury (TRALI)-risk plasma significantly reduces TRALI

    Conversion to low transfusion-related acute lung injury (TRALI)-risk plasma significantly reduces TRALI:

    BACKGROUND: Transfusion-related acute lung injury (TRALI) is an uncommon but serious transfusion reaction. Studies have shown that the transfusion of HLA and HNA antibodies in donor plasma can lead to TRALI. Female donors are more likely to have such antibodies due to alloantigen exposure during pregnancy. Many blood suppliers have now implemented various TRALI risk reduction strategies to unknown effect. A retrospective analysis of TRALI reactions in plasma recipients before and after the conversion to low-TRALI-risk plasma (all-male donor plasma, male-predominant plasma, nulliparous female plasma, and HLA antibody–tested plasma) is reported.

    STUDY DESIGN AND METHODS: Transfusion reaction reports at three large hospitals 16 months before and 16 months after the conversion to low-TRALI-risk plasma were analyzed. Respiratory reactions were categorized as TRALI, possible TRALI, or other (e.g., transfusion-associated circulatory overload or allergic reactions). Reactions were reported as a percentage of total units transfused and rates for the two time periods were compared. Trends in reaction rates for other components were also compared.

    RESULTS: A total of 2156 transfusion reactions in association with 461,598 transfused blood components were reviewed. The incidence of combined TRALI or possible TRALI reactions, due to the transfusion of plasma, decreased from 0.0084% to zero (p = 0.052). The rate of TRALI or possible TRALI reactions in red blood cell and platelet recipients did not change significantly.

    CONCLUSION: The conversion to low-TRALI-risk plasma has reduced the incidence of TRALI reactions in plasma recipients.

    Human leucocyte antigen typing: techniques and technology, a critical appraisal

    Human leucocyte antigen typing: techniques and technology, a critical appraisal


    Methods for the identification of Human Leukocyte Antigens (HLA) have changed significantly since this group of polymorphic proteins were first characterized by serological reagents in the 1960s and 1970s. The invention and development of the Polymerase Chain Reaction (PCR) has been key in the progress of methods for HLA genotyping. As the complexity of HLA polymorphism has unravelled so it has exposed the weaknesses in techniques such as PCR – Restriction Fragment Length Polymorphism (RFLP) and Reference Strand Mediated Conformation Analysis (RSCA), which are no longer in use today. Methods which have been considered routine laboratory tools in recent years, such as Sequence-Specific Primer – PCR and Sequencing Based Typing (SBT) are now also threatened with extinction, not only because of the depth of HLA variation but also because of the rapid development of Next Generation Sequencing and technologies which will follow this. This review describes the merits and disadvantages of current technologies available to HLA Typing laboratories, future trends and the problems posed by new alleles.

    Sunday, November 6, 2011

    Desensitization of HLA-Incompatible Kidney Recipients.:
    N Engl J Med. 2011 Oct 27;365(17):1643-5
    A thoughtful debate about desensitization vs. acceptable mismatch transplantation programs.
    Time for a boycott of Chinese science and medicine pertaining to organ transplantation: Organ transplantation in China has expanded rapidly in the past 20 years. According to official statistics, more than a million people in China need a transplant every year. Many transplants are being done. The China Liver Transplant Registry reports 20 048 recipients between January, 1993, and May 22, 2011. 1475 of these came from living donors. A representative of the Chinese Ministry of Health at the August, 2010, meeting in Vancouver, Canada, of the Transplantation Society reported similar figures.
    Many residents of China might have benefited from kidney, liver, and other forms of transplantation. But the rapid expansion of the capacity to do transplantations has not been accompanied by the development of an ethical system for recovering organs from those who die in hospitals while on life support, as is international practice.2 And even though there is an inadequate supply of organs for its own citizens, there remains a brisk traffic to China to secure organ transplants. Transplant “tourists” find their way to China, frustrated by the long waiting times in their own countries and attracted by the competitive price.3
    It is clear from the numbers provided by China that not all of the organs for Chinese citizens and transplant tourists are provided by voluntary consenting donors. The source of many of these organs is executed prisoners whose consent is either non-existent or ethically invalid and whose demise might be timed for the convenience of the waiting recipient. The Chinese Government has admitted as much on multiple occasions, although insists that it is trying to discourage the practice.
    The use of executed prisoners as a source of organs is a morally reprehensible practice. Use of organs from executed prisoners violates basic human rights and also delays the development in China of ethical strategies for recovering organs.
    Despite the continuation of organ donation by execution, the international medical and scientific community has done little to make its moral abhorrence of this state of affairs widely known. Presentations about transplantation in China continue to be made at international conferences, publications about the experience of transplantation in China appear in peer-reviewed journals, and pharmaceutical companies continue their marketing efforts and engage in sponsoring research involving various aspects of transplantation in China.
    The time has come to bring normal scientific and medical interchange with China concerning transplantation to a halt. We call for a boycott on accepting papers at meetings, publishing papers in journals, and cooperating on research related to transplantation unless it can be verified that the organ source is not an executed prisoner. These steps are admittedly challenging. But the international biomedical community must firmly and boldly challenge the status quo—the barbarous practice of obtaining organs from executed prisoners.

    The Role of Anti-HLA Antibodies in Hematopoietic Stem Cell Transplantation

    Link: Donor-specific antihuman leukocyte antigen antibodies (DSHA) have been clearly implicated in graft rejection in solid organ transplantation. Their role in allogeneic hematopoietic stem-cell transplantation (allo-HSCT) remains unclear. We summarize here evidence supporting a role for DSHA in graft failure in animal models of allo-HSCT and in clinical settings whenever no full HLA matching occurs.

    Friday, November 4, 2011

    The Use of Kidneys with Small Renal Tumors for Transplantation: Who Is Taking the Risk?

    The Use of Kidneys with Small Renal Tumors for Transplantation: Who Is Taking the Risk?:

    The ever-increasing disparity between the number of organs available for transplant and the need for organs drives further exploration into the use of compromised or marginal donors. There is now an emerging advocacy for the use of kidneys with existing tumors, which may be rendered tumor free after surgical excision and reconstruction. This practice is based on reliable data that renal cancers <3 cm in diameter behave with minimal malignant potential and likelihood of transmission to the immunosuppressed recipient. However, in the case of live donors this creates a potential ethical conflict between those treating patients with renal masses and those with an interest in renal donation. The best available treatment for patients with a small renal tumor is a form of nephron-sparing tumor excision or ablation, as this approach provides for the maximum amount of residual kidney function and enhances survival. Thus, patients newly diagnosed with small renal tumors should be referred to centers with expertise in nephron sparing techniques, not transplant centers. In the case of an individual undergoing a live donor evaluation in which a small renal tumor is detected, a careful analysis of risk and benefit for the potential donor and the recipient is indicated.

    Thursday, November 3, 2011

    HLA Antibody Specification Using Single-Antigen Beads—A Technical Solution for the Prozone Effect

    HLA Antibody Specification Using Single-Antigen Beads—A Technical Solution for the Prozone Effect: Background. Substantial progress in human leukocyte antigen antibody specification has been made by the introduction of Luminex single-antigen bead (SAB) assays. This progress was impaired when it turned out that this method is prone to a prozone effect leading to false-negative results in the case of high antibody titers. Testing serum and ethylenediaminetetraacetic acid (EDTA) plasma of one patient in parallel, we observed the prozone effect with the serum sample only. This led us to investigate complement component 1 (C1) as the cause of the prozone in SAB testing. We also found an easy way to overcome the prozone effect.
    Methods. Sera with a prozone effect were tested in the SAB assay, applying different methods of serum pretreatment to explore the parameters leading to the prozone.
    Results. The prozone was not observed when EDTA plasma or serum with EDTA added were tested. Further, addition of dithiothreitol, addition of C1 inhibitor, or heat inactivation of the sera abolished the prozone effect. Adding fresh nonimmune serum to heat-inactivated sera restored the prozone effect. Only beads showing a prozone were found to be covered with C1q.
    Conclusion. Our observations are consistent with the hypothesis that dissociation or destruction of complement C1 eliminates the prozone effect. Addition of EDTA to serum of highly immunized patients is the easiest way to avoid false-negative results in SAB testing caused by a prozone effect.
    Association Between Donor-Specific Antibodies and Acute Rejection and Resolution in Small Bowel and Multivisceral Transplantation: Background. Donor-specific antibodies (DSA) are associated with acute kidney graft rejection, but their role in small bowel/multivisceral allograft remains unclear. We carried out a prospective study to understand the impact of DSA in the setting of intestinal allograft rejection.
    Methods. Thirteen patients (15 grafts) were serially evaluated for DSA levels pre- and posttransplant. DSA was determined by Luminex and the results were interpreted as fluorescence intensity (FI), with FI more than 3000 considered positive.
    Results. The clinical rejection episodes in allografts were significantly associated with the presence of DSA (P=0.041).We obtained 291 biopsy samples from graft ileum and date-matched DSA assay reports. Sixty-three (21.65%) of the biopsies showed acute rejection. The appearance of DSA were preformed (n=5, anti-human leukocyte antigen class II=3, anti-class I and II=2), de novo (n=4, 15.25±4.72 days after transplantation, anti-class II=1, and anti-class I and II=3) and never (n=6). Among the 63 biopsies, 30(47.6%) had significant correlations with positive DSA (kappa=0.30, P<0.001) and manifested severe rejection grade (P=0.009).
    Conclusions. In this cohort of small bowel/multivisceral transplantation patients, there was a high incidence of DSA. The presence of DSA should alert the clinical team of a higher risk of rejection, and reduction of the FI is clinically associated with resolution. Serial endoscopy guided biopsies combined with simultaneous DSA measurement in postintestinal transplantation follow-up is an effective means of screening for cellular and humoral-based forms of acute rejection.
    Antibodies Against Nucleolin in Recipients of Organ Transplants: Background. Patients who reject allografts frequently make strong antibody responses against donor human leukocyte antigens and autoantigens such as vimentin, collagen V, or alpha-tubulin and it has been postulated that autoantibodies may play a role in allograft failure.
    Methods. We have used serum from patients who recently rejected an allograft as a source of antibodies in combination with lysates of human umbilical vein endothelial cells as a source of target antigens. Immunoprecipitation and protein identification was performed by mass spectrometry. Recombinant nucleolin was produced and sera were assayed for antibodies by enzyme-linked immunosorbent assay.
    Results. Immunoprecipitation with serum WW led to the recognition of the protein nucleolin as a target antigen. By enzyme-linked immunosorbent assay, with recombinant nucleolin (r-nucleolin), the frequency of antibodies to nucleolin were found to be 2.0% in normal subjects, 9.1% in patients waiting for a kidney transplant, 25.5% after irreversible rejection of a kidney allograft, 17.1% after a heart transplant, and 43.8% in heart transplant recipients developing transplant-related coronary artery disease. Antibodies against nucleolin from mice or from transplant patients inhibited endothelial cell proliferation and in vitro capillary-like tube formation and caused apoptosis of human umbilical vein endothelial cells.
    Conclusions. Antibodies against nucleolin seem to inhibit and produce apoptosis of proliferating endothelial cells. These antibodies were found in many transplant patients and seemed to be associated with rejection of kidney allografts and with coronary artery disease in heart transplant recipients.

    Wednesday, November 2, 2011

    Underutilization of A2 ABO incompatible kidney transplantation:
    Redfield RR, Parsons RF, Rodriguez E, Mustafa M, Cassuto J, Vivek K, Noorchashm H, Naji A, Levine MH, Abt PL. Underutilization of A2 ABO incompatible kidney transplantation. Clin Transplant 2011 DOI: 10.1111/j.1399-0012.2011.01543.x. © 2011 John Wiley & Sons A/S.
    Abstract:  Background:  ABO compatibility creates a disadvantage for O and B renal allograft candidates. A2 ABO incompatible transplant may decrease waiting times and generate equivalent graft survival to an ABO compatible transplant.
    Methods:  Death-censored graft survival was compared between A recipients and O, B, and AB recipients of an A2 allograft with multivariate Cox regression models utilizing data from the United Network of Organ Sharing (UNOS) between 1997 and 2007.
    Results:  Eighty-five percent of A2 kidneys were transplanted into ABO compatible recipients vs. 15% into ABO incompatible recipients. Rates of A2 incompatible kidney transplants did not increase over the study period (14.8% to 14.6%). Mean wait time for A2→O kidneys was 337 vs. 684 d for O→O and for A2→B kidneys, 542 vs. 734 d for B→B. Adjusted relative risk of graft loss at five-yr was similar between O, B, and AB recipients compared to A recipients of an A2 allograft, corresponding to a five-yr graft survival of 84%, 86.2%, 86.1%, and 86.1%, respectively.
    Conclusion:  A2 incompatible kidney transplantation is underutilized. Graft outcomes are similar among A2 compatible and incompatible recipients. Shorter waiting time and improved access might be achieved if A2 kidneys are considered in all blood groups.
    Donor-Specific Antibody Against Denatured HLA-A1: Clinically Non-Significant?: Authors: Pereira S, Perkins S, Lee JH, Shumway W, Lefor W, Lopez-Cepero M, Wong C, Connolly A, Tan JC, Grumet FC
    Pre-transplant screening of a female with ESRD showed no anti-HLA alloantibodies by AHG-CDC (Class I) or ELISA (Class II). Following a negative AHG-CDC crossmatch, an HLA*01:01+ DD kidney was transplanted in 09/05. Subsequent screening of pre-txplt serum by LABScreen® Single Antigen (SA) array showed strong reactivity vs. A*01:01. Despite that reactivity, at 5 years post-txplt the patient has a serum creatinine of 1.6 mg/dl and has never suffered humoral or cellular rejection. Retrospective FXM of pre- and post-txplt sera vs. DD cells was negative. Rescreening of multiple pre and post-txplt sera revealed anti-A1 reactivity persisting from the very first through the last sam...
    Major histocompatibility complex class I-related chain A allele mismatching, antibodies, and rejection in renal transplantation.: Authors: Cox ST, Stephens HA, Fernando R, Karasu A, Harber M, Howie AJ, Powis S, Zou Y, Stastny P, Madrigal JA, Little AM
    Even when kidney allografts are well matched for human leukocyte antigen (HLA) and anti-HLA antibodies are not detected, graft rejection can still occur. There is evidence that some patients who lose their graft have antibodies specific for major histocompatibility complex (MHC) class I-related chain A (MICA) antigens. We investigated whether mismatching MICA alleles associates with MICA antibody production and graft rejection or dysfunction. MICA and HLA antibody screening in 442 recipients was performed, and specificities were confirmed in a subgroup of 227 recipients using single-antigen multiplex technology. For assignment of MICA antibody specificity, we used t...
    Heart transplantation with donor-specific antibodies directed toward denatured HLA-A*02:01: a case report.: In this report, we describe the case of a heart transplanted patient who exhibited anti-HLA-A*02:01 donor-specific antibodies detected with a bead-based assay (Luminex) and undetected with the complement-dependent cytotoxicity (CDC) test. Posttransplant monitoring, carried out with CDC and with Luminex on sera from this patient collected at the 2nd, 4th, 8th, and 12th posttransplant weeks and at 1 year confirmed the presence of anti-HLA-A*02:01 in all serum samples. Additional tests carried out with denatured and intact HLA molecules using single antigen beads demonstrated that the antibody was directed toward a cryptic epitope. One year after transplantation the patient is doing well. No sign of antibody-mediated rejection was observed throughout the follow-up. A comprehensive evaluation ...
    Influenza Vaccination in the Organ Transplant Recipient: Review and Summary Recommendations†:
    Influenza virus causes a spectrum of illness in transplant recipients with a high rate of lower respiratory disease. Seasonal influenza vaccination is an important public health measure recommended for transplant recipients and their close contacts. Vaccine has been shown to be safe and generally well tolerated in both adult and pediatric transplant recipients. However, responses to vaccine are variable and are dependent on various factors including time from transplantation and specific immunosuppressive medication. Seasonal influenza vaccine has demonstrated safety and no conclusive evidence exists for a link between vaccination and allograft dysfunction. Annually updated trivalent inactivated influenza vaccines have been available and routinely used for several decades, although newer influenza vaccination formulations including high-dose vaccine, adjuvanted vaccine, quadrivalent inactivated vaccine and vaccine by intradermal delivery system are now available or will be available in the near future. Safety and immunogenicity data of these new formulations in transplant recipients requires investigation. In this document, we review the current state of knowledge on influenza vaccines in transplant recipients and make recommendations on the use of vaccine in both adult and pediatric organ transplant recipients.

    Three-Year Outcomes from BENEFIT, a Randomized, Active-Controlled, Parallel-Group Study in Adult Kidney Transplant Recipients

    Three-Year Outcomes from BENEFIT, a Randomized, Active-Controlled, Parallel-Group Study in Adult Kidney Transplant Recipients:

    The clinical profile of belatacept in kidney transplant recipients was evaluated to determine if earlier results in the BENEFIT study were sustained at 3 years. BENEFIT is a randomized 3 year, phase III study in adults receiving a kidney transplant from a living or standard criteria deceased donor. Patients were randomized to a more (MI) or less intensive (LI) regimen of belatacept, or cyclosporine. 471/666 patients completed ≥3 years of therapy. A total of 92% (MI), 92% (LI), and 89% (cyclosporine) of patients survived with a functioning graft. The mean calculated GFR (cGFR) was ∼21 mL/min/1.73 m2 higher in the belatacept groups versus cyclosporine at year 3. From month 3 to month 36, the mean cGFR increased in the belatacept groups by +1.0 mL/min/1.73 m2/year (MI) and +1.2 mL/min/1.73 m2/year (LI) versus a decline of −2.0 mL/min/1.73 m2/year (cyclosporine). One cyclosporine-treated patient experienced acute rejection between year 2 and year 3. There were no new safety signals and no new posttransplant lymphoproliferative disorder (PTLD) cases after month 18. Belatacept-treated patients maintained a high rate of patient and graft survival that was comparable to cyclosporine-treated patients, despite an early increased occurrence of acute rejection and PTLD.