Lung transplantation despite preformed donor-specific antihuman leukocyte antigen antibodies: a 9-year single-center experience.

Pretransplant allosensitization to human leukocyte antigens (HLA) increases the recipient's waiting list time and mortality in lung transplantation. Rather than waiting for crossmatch-negative donors, since 2013, recipients with preformed donor-specific antiHLA antibodies (pfDSA) have been managed with repeated IgA- and IgM-enriched intravenous immunoglobulin (IgGAM) infusions, usually in combination with plasmapheresis before IgGAM and a single dose of antiCD20 antibody. This retrospective study presents our 9-year experience with patients transplanted with pfDSA. Records of patients transplanted between February 2013 and May 2022 were reviewed. Outcomes were compared between patients with pfDSA and those without any de novo donor-specific antiHLA antibodies. The median follow-up time was 50 months. Of the 1,043 patients who had undergone lung transplantation, 758 (72.7%) did not develop any early donor-specific antiHLA antibodies, and 62 (5.9%) patients exhibited pfDSA. Among the 52 (84%) patients who completed treatment, pfDSA was cleared in 38 (73%). In pfDSA vs control patients and at 8-year follow-up, respectively, graft survival (%) was 75 vs 65 (P = .493) and freedom from chronic lung allograft dysfunction (%) was 63 vs 65 (P = .525). In lung transplantation, crossing the preformed HLA-antibody barrier is safe using a treatment protocol based on IgGAM. Patients with pfDSA have a good 8-year graft survival rate and freedom from chronic lung allograft dysfunction, similar to control patients.

Heart transplantation across preformed donor-specific antibody barriers using a perioperative desensitization protocol.

Heart transplantation across preformed donor-specific HLA-antibody barriers is associated with impaired short- and long-term survival. Therefore, in recipients with preformed anti-HLA antibodies, waiting for crossmatch-negative donors is standard practice. As an alternative strategy, recipients with preformed anti-HLA donor specific antibodies have been managed at our institutions with a perioperative desensitization regimen. A retrospective analysis was performed comparing heart transplant recipients with preformed donor-specific HLA-antibodies to recipients without donor-specific antibodies. Recipients with a positive virtual crossmatch received a perioperative desensitization protocol including tocilizumab intraoperatively, plasma exchange and rituximab followed by a six-month course of IgGAM. Among the 117 heart-transplanted patients, 19 (16%) patients underwent perioperative desensitization, and the remaining 98 (84%) patients did not. Cold ischemic time, posttransplant extracorporeal life support for primary graft dysfunction, and intensive care unit stay time did not differ between groups. At 1-year follow-up, freedom from pulsed steroid therapy for presumed rejection and biopsy-confirmed acute cellular or humoral rejection did not differ between groups. One-year survival amounted to 94.7% in the treated patients and 81.4% in the control group. Therefore, heart transplantation in sensitized recipients undergoing a perioperative desensitization appears safe with comparable postoperative outcomes as patients with a negative crossmatch.

Steering Transplant Immunosuppression by Measuring Virus-Specific T Cell Levels: The Randomized, Controlled IVIST Trial.

BACKGROUND: Pharmacokinetic monitoring is insufficient to estimate the intensity of immunosuppression after transplantation. Virus-specific T cells correlate with both virus-specific and general cellular immune defense. Additional steering of immunosuppressive therapy by virus-specific T cell levels might optimize dosing of immunosuppressants. METHODS: In a multicenter, randomized, controlled trial, we randomized 64 pediatric kidney recipients to a control group with trough-level monitoring of immunosuppressants or to an intervention group with additional steering of immunosuppressive therapy by levels of virus-specific T cells (quantified by cytokine flow cytometry). Both groups received immunosuppression with cyclosporin A and everolimus in the same target range of trough levels. Primary end point was eGFR 2 years after transplantation. RESULTS: In the primary analysis, we detected no difference in eGFR for the intervention and control groups 2 years after transplantation, although baseline eGFR 1 month after transplantation was lower in the intervention group versus the control group. Compared with controls, patients in the intervention group received significantly lower daily doses of everolimus and nonsignificantly lower doses of cyclosporin A, resulting in significantly lower trough levels of everolimus (3.5 versus 4.5 µg/L, P<0.001) and cyclosporin A (47.4 versus 64.1 µg/L, P<0.001). Only 20% of patients in the intervention group versus 47% in the control group received glucocorticoids 2 years after transplantation (P=0.04). The groups had similar numbers of donor-specific antibodies and serious adverse events. CONCLUSIONS: Steering immunosuppressive therapy by virus-specific T cell levels in addition to pharmacokinetic monitoring seems safe, results in a similar eGFR, and personalizes immunosuppressive therapy by lowering exposure to immunosuppressive drugs, likely resulting in lower drug costs. CLINICAL TRIAL REGISTRY NAME AND REGISTRATION NUMBER: IVIST trial, https://www.clinicaltrialsregister.eu/ctr-search/search?query=2009-012436-32 and ISRCTN89806912.

B cell depletion impairs vaccination-induced CD8+ T cell responses in a type I interferon-dependent manner.

OBJECTIVES: The monoclonal anti-CD20 antibody rituximab is frequently applied in the treatment of lymphoma as well as autoimmune diseases and confers efficient depletion of recirculating B cells. Correspondingly, B cell-depleted patients barely mount de novo antibody responses during infections or vaccinations. Therefore, efficient immune responses of B cell-depleted patients largely depend on protective T cell responses. METHODS: CD8+ T cell expansion was studied in rituximab-treated rheumatoid arthritis (RA) patients and B cell-deficient mice on vaccination/infection with different vaccines/pathogens. RESULTS: Rituximab-treated RA patients vaccinated with Influvac showed reduced expansion of influenza-specific CD8+ T cells when compared with healthy controls. Moreover, B cell-deficient JHT mice infected with mouse-adapted Influenza or modified vaccinia virus Ankara showed less vigorous expansion of virus-specific CD8+ T cells than wild type mice. Of note, JHT mice do not have an intrinsic impairment of CD8+ T cell expansion, since infection with vaccinia virus induced similar T cell expansion in JHT and wild type mice. Direct type I interferon receptor signalling of B cells was necessary to induce several chemokines in B cells and to support T cell help by enhancing the expression of MHC-I. CONCLUSIONS: Depending on the stimulus, B cells can modulate CD8+ T cell responses. Thus, B cell depletion causes a deficiency of de novo antibody responses and affects the efficacy of cellular response including cytotoxic T cells. The choice of the appropriate vaccine to vaccinate B cell-depleted patients has to be re-evaluated in order to efficiently induce protective CD8+ T cell responses.

Generating low immunogenic pig pancreatic islet cell clusters for xenotransplantation.

Xenotransplantation of pancreatic islets offers a promising alternative to overcome the shortage of allogeneic donors. Despite significant advances, either immune rejection or oxygen supply in immune protected encapsulated islets remains major bottlenecks for clinical application. To decrease xenogeneic immune responses, we generated tissue engineered swine leucocyte antigen (SLA)-silenced islet cell clusters (ICC). Single-cell suspensions from pancreatic islets were generated by enzymatic digestion of porcine ICCs. Cells were silenced for SLA class I and class II by lentiviral vectors encoding for short hairpin RNAs targeting beta2-microglobulin or class II transactivator, respectively. SLA-silenced ICCs-derived cells were then used to form new ICCs in stirred bioreactors in the presence of collagen VI. SLA class I silencing was designed to reach a level of up to 89% and class II by up to 81% on ICCs-derived cells. Xenogeneic T cell immune responses, NK cell and antibody-mediated cellular-dependent immune responses were significantly decreased in SLA-silenced cells. In stirred bioreactors, tissue engineered islets showed the typical 3D structure and insulin production. These data show the feasibility to generate low immunogenic porcine ICCs after single-cell engineering and post-transduction islet reassembling that might serve as an alternative to allogeneic pancreatic islet cell transplantation.

Variation in the Human Leukocyte Antigen system and risk for endemic Burkitt lymphoma in northern Uganda.

Endemic Burkitt lymphoma (eBL) is an aggressive childhood B-cell lymphoma associated with Plasmodium falciparum (Pf) malaria and Epstein-Barr virus (EBV) infections. Variation in the Human Leukocyte Antigen (HLA) system is suspected to play a role, but assessments using less accurate serology-based HLA typing techniques in small studies yielded conflicting results. We studied 200 eBL cases and 400 controls aged 0-15 years enrolled in northern Uganda and typed by accurate high-resolution HLA sequencing methods. HLA results were analyzed at one- or two-field resolution. Odds ratios and 95% confidence intervals (aOR, 95% CI) for eBL risk associated with common HLA alleles versus alleles that were rare (<1%) or differed by <2% between the cases and controls as the reference category, were estimated using multiple logistic regression adjusting for age, sex, microgeography, region, malaria positivity and treatment history, and genetic variants associated with eBL. Compared to the controls, eBL cases had a lower frequency of HLA-A*02 (aOR = 0·59, 95% CI 0·38-0·91), HLA-B*41 (aOR = 0·36, 95% CI 0·13-1·00), and HLA-B*58 alleles (aOR = 0·59, 95% CI 0·36-0·97). eBL cases had a lower frequency of HLA-DPB1 homozygosity (aOR = 0·57, 95% CI 0·40-0·82) but a higher frequency of HLA-DQA1 homozygosity (aOR = 2·19, 95% CI 1·42-3·37). Our results suggest that variation in HLA may be associated with eBL risk.

Two novel antithetical KN blood group antigens may contribute to more than a quarter of all KN antisera in Europe.

BACKGROUND: All antigens described in the KN blood group system are located in the long homologous repeat D (LHR-D) of complement receptor 1 (CR1). While there have been reports that some sera react only with the long homologous repeat C (LHR-C), the antigens in LHR-C are unknown. STUDY DESIGN AND METHODS: Recombinant LHR-C and LHR-D were used to identify antibodies directed against LHR-C of CR1, into which a point mutation was introduced to characterize the underlying blood group antigens. In addition, database studies to define haplotypes of CR1 were performed. RESULTS: Several antisera were identified that were specific against CR1 p.1208His and against CR1 p.1208Arg, located in LHR-C. Fifteen KN haplotypes were found in the Ensembl genome browser. It was shown that due to a linkage disequilibrium anti-CR1 p.1208His may be mistaken for anti-KCAM. CONCLUSION: A novel antithetical KN blood group antigen pair was found at position p.1208 of CR1, for which the names DACY and YCAD are proposed. Antibodies against these two novel antigens seem to contribute to more than a quarter of all KN sera in Europe.

Increased frequency of CD4+ CD25high CD127low T cells early after lung transplant is associated with improved graft survival - a retrospective study.

In this retrospective study, we analyzed the presence of any association of three CD4+ CD25high regulatory T-cell subpopulations at 3 weeks after lung transplantation with the later incidence of chronic lung allograft dysfunction and graft survival. Among lung-transplanted patients between January 2009 and April 2018, only patients with sufficient T-cell measurements at 3 weeks after transplantation were included into the study. Putative regulatory T cells were defined as CD4+ CD25high T cells, detected in peripheral blood and further analyzed for CD127low , FoxP3+ , and CD152+ using fluorescence-activated cell sorting (FACS) analysis. Associations of regulatory T cells with chronic lung allograft dysfunction (CLAD) and graft survival were evaluated using Cox analysis. During the study period, 724 (71%) patients were included into the study. Freedom from chronic lung allograft dysfunction (CLAD) and graft survival amounted to 66% and 68% at 5 years. At the multivariable analysis, increasing frequencies of CD127low were associated with better freedom from CLAD (hazard ratio for each 1% increase of %CD127low , HR = 0.989, 95% CI = 0.981-0.996, P = 0.003) and better graft survival (HR = 0.991, 95% CI = 0.984-0.999, P = 0.026). A higher frequency of CD127low regulatory T cells in peripheral blood early after lung transplantation estimated a protective effect against chronic lung allograft dysfunction, mortality, and re-transplantation.

Preemptive treatment of early donor-specific antibodies with IgA- and IgM-enriched intravenous human immunoglobulins in lung transplantation.

This retrospective study presents our 4-year experience of preemptive treatment of early anti-HLA donor specific antibodies with IgA- and IgM-enriched immunoglobulins. We compared outcomes between patients with antibodies and treatment (case patients) and patients without antibodies (control patients). Records of patients transplanted at our institution between March 2013 and November 2017 were reviewed. The treatment protocol included one single 2 g/kg immunoglobulin infusion followed by successive 0.5 g/kg infusions for a maximum of 6 months, usually combined with a single dose of anti-CD20 antibody and, in case of clinical rejection or positive crossmatch, with plasmapheresis or immunoabsorption. Among the 598 transplanted patients, 128 (21%) patients formed the case group and 452 (76%) the control group. In 116 (91%) patients who completed treatment, 106 (91%) showed no antibodies at treatment end. Fourteen (13%) patients showed antibody recurrence thereafter. In case versus control patients and at 4-year follow-up, respectively, graft survival (%) was 79 versus 81 (P = .59), freedom (%) from biopsy-confirmed rejection 57 versus 53 (P = .34), and from chronic lung allograft dysfunction 82 versus 78 (P = .83). After lung transplantation, patients with early donor-specific antibodies and treated with IgA- and IgM-enriched immunoglobulins had 4-year graft survival similar to patients without antibodies and showed high antibody clearance.

Graft outcomes following diagnosis of post-transplant lymphoproliferative disease in pediatric kidney recipients: a retrospective study.

Data related to graft outcomes following post-transplant lymphoproliferative disease (PTLD) in pediatric kidney transplantation are scarce. Data were analyzed retrospectively from 12 children (eight boys) for 3 years after diagnosis of PTLD, with a loss of follow-up after 2 years in two of 12. In all cases, intensity of immunosuppressive therapy was reduced, which switched from calcineurin inhibitor to a mammalian target of rapamycin (mTOR) inhibitor in ten cases. Nine children were treated with six doses of rituximab according to the PED-PTLD-2005 protocol, with additional treatment in one child as per protocol. One patient received EuroNet-PHL C1. In four patients, donor-specific antibodies were detected after PTLD diagnosis at 3, 4, 5 and 7 years, respectively. One patient developed chronic antibody-mediated rejection (cAMR) 12 years after diagnosis, losing the graft 1 year later. Three patients with recurrence of the original disease also lost their grafts, one at the time of diagnosis of PTLD, and two after 4 years. Range-based analysis of variance showed that there was no decrease in estimated GFR at 1, 2, or 3 years after diagnosis of PTLD (P = 0.978). In conclusion, treatment of PTLD with reduced immunosuppression is safe and efficient. This may be due to B-cell-depleting therapy of PTLD with rituximab.

Correction to: Rabbit anti-human thymocyte immunoglobulin for the rescue treatment of chronic antibody-mediated rejection after pediatric kidney transplantation.

The article "Rabbit anti-human thymocyte immunoglobulin for the rescue treatment of chronic antibody-mediated rejection after pediatric kidney transplantation", written by Yasemen Cihan, Nele Kanzelmeyer, Jens Drube, Martin Kreuzer, Christian Lerch, Imke Hennies, Kerstin Froede, Murielle Verboom.

Belatacept after kidney transplantation in adolescents: a retrospective study.

Regardless of recipient age at kidney transplantation (KTx), patients are at greatest risk for graft loss in adolescence, partly due to nonadherence to an oral immunosuppressive regimen. Belatacept, a non-nephrotoxic, first-in-class immunosuppressant that inhibits costimulation of T cells requires intravenous application only every 4 weeks, potentially leading to better adherence. However, it is only approved for use in adults. We report here the findings of the first study of belatacept in adolescents, comprising all patients in our department switched to belatacept post-KTx. Six patients (median age 15.5 years) were switched after a median of 7.5 months (range 23 days to 12 years), treatment range 3-28 months (cumulative 83 months): Three patients switched early (<3 months after KTx) had increased estimated glomerular filtration rate (GFR); one patient switched 12 years post-KTx has stable GFR; two patients were switched following rapid decline of and with markedly impaired GFR, changing slope in one patient. One patient had one acute rejection. In addition of two patients who received belatacept for other conditions, the only relevant adverse event was neutropenia (after a cumulative 109 months). Belatacept as primary immunosuppression is an option in Epstein-Barr virus-seropositive nonadherent adolescents if administered sufficiently early before deterioration of graft function.

Rabbit anti-human thymocyte immunoglobulin for the rescue treatment of chronic antibody-mediated rejection after pediatric kidney transplantation.

BACKGROUND: Chronic antibody-mediated rejection (cAMR) is the leading cause of late kidney graft loss, but current therapies are often ineffective. Rabbit anti-human thymocyte immunoglobulin (rATG) may be helpful, but its use is virtually undocumented. METHODS: Data were analyzed retrospectively from nine pediatric kidney transplant patients with cAMR were treated with rATG (1.5 mg/kg × 5 days) at our center after non-response to pulsed prednisolone, intravenous immunoglobulin, rituximab, and increased immunosuppressive intensity (including switching to belatacept in some cases), with or without bortezomib. RESULTS: The median time from diagnosis to cAMR was 179 days. rATG was started 5-741 days after diagnosis. Median estimated glomerular filtration rate (eGFR) increased from 40 mL/min/1.73 m2 when rATG was started to 62 mL/min/1.73 m2 9 months later (p = 0.039). Four patients showed substantially higher eGFR after 9 months and 2 patients showed a small improvement; eGFR continued to decline in 3 patients after starting rATG. No grafts were lost during follow-up. At last follow-up, donor-specific antibodies (DSAs) were no longer detectable in 4 out of 8 patients for whom data were available, median fluorescence intensity had decreased substantially in 1 out of 8 patients; anti-HLA DQ DSAs persisted in 2 out of 8 patients. No adverse events with a suspected relation to rATG, including allergic reactions, leukocytopenia or infections, were observed in any of the patients. CONCLUSIONS: In this small series of patients, rATG appears a promising treatment for unresponsive cAMR. Further evaluation, including earlier introduction of rATG, is warranted.

Human leucocyte antigens and pediatric autoimmune liver disease: diagnosis and prognosis.

UNLABELLED: An association of human leukocyte antigen (HLA) class II alleles with autoimmune conditions is increasingly being used for diagnostic purposes. The aim of our study was to examine whether HLA class II alleles in pediatric-onset autoimmune liver disease (pAILD) may serve as diagnostic markers and if they correlate with clinical outcome parameters. HLA-DRB1 alleles of 76 children with pAILD (autoimmune hepatitis [AIH], autoimmune sclerosing cholangitis [AISC], primary sclerosing cholangitis [PSC]) and of 50 healthy blood donors as control group were analyzed retrospectively. Diagnosis of these patients was confirmed by the autoimmune hepatitis score including liver histology, which has been re-evaluated by a blinded liver pathologist, and by bile duct imaging, as appropriate. Our results showed significant association of HLA-DRB1*03 with AIH1 and AISC with 82 % specificity for AIH. For pAILD (excluding AIH2), HLA-DRB1*03 homozygosity had specificity of 98 %, whereas sensitivity is low. Remission in HLA-DRB1*03-positive patients appears to be less likely. HLA-DRB1*13 is significantly associated with PSC and also with AIH1. CONCLUSION: HLA-DRB1 alleles provide supportive information for diagnostic workup in patients with liver disease, but they were not suitable for differentiation within pAILD. Their prognostic value could be helpful but needs to be evaluated further. WHAT IS KNOWN: • HLA-DRB1*03 is NOT associated with pediatric AIH in a previous national study. • In other studies, HLA-DRB1*03 is associated with AIH1. • HLA-DRB1*13 is associated with PSC. • HLA-DRB1*04 is described as protective for AILD. What is New: • HLA-DRB1 four-digit typing for all alleles and for all subgroups of pAILD combined with re-assessment of liver histology • HLA-DRB1*03:01 is associated with pediatric AIH1 and AISC. • HLA-DRB1*03:01 appears to be a prognostic marker. • HLA-DRB1*13:01 is associated with pediatric AIH1 in mixed ethnicity cohort. • HLA-DRB1*04 does not show any protective effect for pAILD.

Semaphorin 3A alters endothelial cell immunogenicity by regulating Class II transactivator activity circuits.

BACKGROUND: Endothelial cells (ECs) play a pivotal role in the allogeneic immune response upon transplantation. Semaphorin 3A (Sema3A) was implicated in the modulation of EC growth, but its effects on immunogenicity were not previously investigated. STUDY DESIGN AND METHODS: ECs were transduced with a lentiviral vector encoding for the green fluorescence protein (GFP) sequence under the control of a Class II transactivator (CIITA)-dependent promoter. Upon stimulation of nonmodified ECs with recombinant Sema3A protein, mRNA and protein levels of CIITA, HLA-DR, and Sema3A receptors were evaluated. An enzyme-linked immunosorbent assay was developed to quantify Sema3A levels in the sera of kidney-transplanted patients. RESULTS: Sema3A stimulation of lentiviral vector encoding for the GFP sequence ECs caused a significant up regulation of the transgene expression, indicating an increase in CIITA levels. Stimulation of nonmodified ECs with Sema3A resulted in an up regulation of CIITA expression, which was associated with enhanced HLA-DR levels and an increase in alloreactive CD4+ T-cell proliferation. Sema3A receptor expression was enhanced by CIITA, establishing a positive feedback loop. Higher levels of Sema3A were observed in sera of patients presenting with organ rejection. CONCLUSION: This study links Sema3A signaling in ECs with increased CIITA levels and higher HLA-DR expression, resulting in CD4+ T-cell activation, which might have important implications for tissue and organ transplantation.

Risk Stratification Before Living Donor Kidney Transplantation in Patients With Preformed Donor-specific Antibodies by Different Crossmatch Methods.

Background: Preformed donor-specific HLA antibodies (DSA) are a well-known risk factor in kidney transplantation. There is still considerable debate, however, about the optimal risk stratification among patients with preformed DSA. Additionally, data on the prognostic value of different crossmatch assays in DSA-positive patients are scarce. Methods: DSA-positive living kidney transplant recipients were selected from a multicenter study examining 4233 consecutive renal transplants. An additional 7 patients from 2 further centers were included. Flow cytometric crossmatches (FXM), Luminex-based crossmatches, and virtual crossmatches based on C1q- and C3d-binding antibodies (C1qXM and C3dXM) were performed retrospectively using pretransplant sera and lymphocytes isolated from fresh samples. These samples were obtained from 44 donor and recipient pairs from 12 centers. Clinical outcome data and the control group without DSA were compiled from the previous study and were supplemented by data on 10-y death-censored graft survival (10yGS). Results: Between 19% (C3dXM) and 46% (FXM) of crossmatches were positive. Crossmatch-positive patients showed high incidences of antibody-mediated rejection (AMR) within 6 mo (up to 60% in B-cell FXM+ patients). The incidence of AMR in crossmatch-negative patients ranged between 5% (FXM-) and 13% (C1qXM-). 10yGS was significantly impaired in patients with positive T-cell FXM and total FXM compared with both patients without DSA and those with DSA with negative FXM. Conclusions: Especially FXM are useful for risk stratification, as the outcome of DSA-positive, FXM-negative patients is similar to that of DSA-negative patients, whereas FXM-positive patients have both more AMR and decreased 10yGS. Because of their lower sensitivity, the significance of Luminex-based crossmatches, C1qXM, and C3dXM would have to be examined in patients with stronger DSA.

Human leukocyte antigen-DQA1*04:01 and rs2040406 variants are associated with elevated risk of childhood Burkitt lymphoma.

Burkitt lymphoma (BL) is responsible for many childhood cancers in sub-Saharan Africa, where it is linked to recurrent or chronic infection by Epstein-Barr virus or Plasmodium falciparum. However, whether human leukocyte antigen (HLA) polymorphisms, which regulate immune response, are associated with BL has not been well investigated, which limits our understanding of BL etiology. Here we investigate this association among 4,645 children aged 0-15 years, 800 with BL, enrolled in Uganda, Tanzania, Kenya, and Malawi. HLA alleles are imputed with accuracy >90% for HLA class I and 85-89% for class II alleles. BL risk is elevated with HLA-DQA1*04:01 (adjusted odds ratio [OR] = 1.61, 95% confidence interval [CI] = 1.32-1.97, P = 3.71 × 10-6), with rs2040406(G) in HLA-DQA1 region (OR = 1.43, 95% CI = 1.26-1.63, P = 4.62 × 10-8), and with amino acid Gln at position 53 versus other variants in HLA-DQA1 (OR = 1.36, P = 2.06 × 10-6). The associations with HLA-DQA1*04:01 (OR = 1.29, P = 0.03) and rs2040406(G) (OR = 1.68, P = 0.019) persist in mutually adjusted models. The higher risk rs2040406(G) variant for BL is associated with decreased HLA-DQB1 expression in eQTLs in EBV transformed lymphocytes. Our results support the role of HLA variation in the etiology of BL and suggest that a promising area of research might be understanding the link between HLA variation and EBV control.

CMV-, EBV- and ADV-specific T cell immunity: screening and monitoring of potential third-party donors to improve post-transplantation outcome.

Adoptive immunotherapy with virus-specific T lymphocytes can efficiently reconstitute antiviral immunity against cytomegalovirus (CMV), Epstein-Barr virus (EBV), and adenovirus (ADV) without causing acute toxicity or increasing the risk of graft-versus-host disease. To gain insight into antiviral T cell repertoires and to identify the most efficient antigens for immunotherapy, the frequencies of CMV-, EBV- and ADV-specific T cells in 204 HLA-typed healthy donors were assessed using viral peptides and peptide pools. Confirmatory testing for CMV serology by Western blot technique revealed 19 of 143 (13%) false-positive results. We observed highly significant individual and overall differences in T cell frequencies against CMV, EBV, and ADV antigens, whereas antigen-specific T cells were detected in 100% of CMV- seropositive donors, 73% of EBV- seropositive donors, and 73% of ADV-seropositive donors. At least 124 (61%) potential T cell donors were identified for each virus. Among the tested antigens, frequencies for CMVpp65 and EBVBZLF1 peptide pools were highest. Short-term in vitro peptide stimulation revealed that a donor response to a certain ADV- and EBV-derived peptide may not be determined without prior stimulation. A modified granzyme B ELISpot was used to detect T cell specificity and alloreactivity. Treatment with allogeneic virus-specific cytotoxic T lymphocytes from seropositive third-party donors may be a feasible therapeutic option for infections following cord-blood stem cell transplantation or hematopoietic stem cell transplantation from virus-seronegative donors.

Four-year allograft survival in a highly sensitized combined liver-kidney transplant patient despite unsuccessful anti-HLA antibody reduction with rituximab, splenectomy, and bortezomib.

Although donor-specific lymphocytotoxic antibodies are regarded as a contraindication for kidney transplantation (KTx), the data available for liver or combined liver or kidney transplantation (cLKTx) are scarce. Here, we report a case of a highly sensitized young man receiving his sixth liver and second kidney graft. Multiple anti-HLA antibodies were present at the time of transplantation. As a result of suspected antibody-mediated graft damage, the patient was treated with rituximab, plasmapheresis, intravenous immunoglobulins, splenectomy, and bortezomib to decrease the antibody production. So far, patient and allograft survival has reached 4 years despite failure to achieve a permanent reduction of anti-HLA antibodies, and particularly nondonor directed antibodies.

Next generation sequencing reveals a novel HLA-C allele, HLA-C*16:201.

HLA-C*16:201 differs from HLA-HLA-C*16:01:01 by one nucleotide substitution in codon 73 (ACT ->GCT).