Identification of the novel HLA-C*05:279 allele in a Spanish renal transplant recipient.

Identification of the novel HLA-C*05:279 allele that differs from C*05:01:01:11 by two nucleotide substitutions.

Characterization of the novel HLA-A*33:237 allele by sequencing-based typing.

A novel HLA-A*33 allele, officially designated HLA-A*33:237, was identified by next-generation sequencing.

Identification of the novel HLA-DQA1*02:01:09:01 allele by two different next-generation sequencing platforms.

A synonymous nucleotide substitution in exon 3 results in the novel HLA-DQA1*02:01:09:01 allele.

Clinical Relevance of Corticosteroid Withdrawal on Graft Histological Lesions in Low-Immunological-Risk Kidney Transplant Patients.

The impact of corticosteroid withdrawal on medium-term graft histological changes in kidney transplant (KT) recipients under standard immunosuppression is uncertain. As part of an open-label, multicenter, prospective, phase IV, 24-month clinical trial (ClinicalTrials.gov, NCT02284464) in low-immunological-risk KT recipients, 105 patients were randomized, after a protocol-biopsy at 3 months, to corticosteroid continuation (CSC, n = 52) or corticosteroid withdrawal (CSW, n = 53). Both groups received tacrolimus and MMF and had another protocol-biopsy at 24 months. The acute rejection rate, including subclinical inflammation (SCI), was comparable between groups (21.2 vs. 24.5%). No patients developed dnDSA. Inflammatory and chronicity scores increased from 3 to 24 months in patients with, at baseline, no inflammation (NI) or SCI, regardless of treatment. CSW patients with SCI at 3 months had a significantly increased chronicity score at 24 months. HbA1c levels were lower in CSW patients (6.4 ± 1.2 vs. 5.7 ± 0.6%; p = 0.013) at 24 months, as was systolic blood pressure (134.2 ± 14.9 vs. 125.7 ± 15.3 mmHg; p = 0.016). Allograft function was comparable between groups and no patients died or lost their graft. An increase in chronicity scores at 2-years post-transplantation was observed in low-immunological-risk KT recipients with initial NI or SCI, but CSW may accelerate chronicity changes, especially in patients with early SCI. This strategy did, however, improve the cardiovascular profiles of patients.

Impact of HLA Mismatching on Early Subclinical Inflammation in Low-Immunological-Risk Kidney Transplant Recipients.

The impact of human leukocyte antigen (HLA)-mismatching on the early appearance of subclinical inflammation (SCI) in low-immunological-risk kidney transplant (KT) recipients is undetermined. We aimed to assess whether HLA-mismatching (A-B-C-DR-DQ) is a risk factor for early SCI. As part of a clinical trial (Clinicaltrials.gov, number NCT02284464), a total of 105 low-immunological-risk KT patients underwent a protocol biopsy on the third month post-KT. As a result, 54 presented SCI, showing a greater number of total HLA-mismatches (p = 0.008) and worse allograft function compared with the no inflammation group (48.5 ± 13.6 vs. 60 ± 23.4 mL/min; p = 0.003). Multiple logistic regression showed that the only risk factor associated with SCI was the total HLA-mismatch score (OR 1.32, 95%CI 1.06-1.64, p = 0.013) or class II HLA mismatching (OR 1.51; 95%CI 1.04-2.19, p = 0.032) after adjusting for confounder variables (recipient age, delayed graft function, transfusion prior KT, and tacrolimus levels). The ROC curve illustrated that the HLA mismatching of six antigens was the optimal value in terms of sensitivity and specificity for predicting the SCI. Finally, a significantly higher proportion of SCI was seen in patients with >6 vs. ≤6 HLA-mismatches (62.3 vs. 37.7%; p = 0.008). HLA compatibility is an independent risk factor associated with early SCI. Thus, transplant physicians should perhaps be more aware of HLA mismatching to reduce these early harmful lesions.

Combining Three Different Pretransplantation Scores Improves Predictive Value in Patients after Haploidentical Stem Cell Transplantation with Thiotepa, Busulfan, and Fludarabine Conditioning and Post-Transplantation Cyclophosphamide.

One hundred and sixty-one patients underwent haploidentical stem cell transplantation (haploSCT) with thiotepa, busulfan, and fludarabine conditioning followed by post-transplantation cyclophosphamide (PTCy) (on days +3 and +4) and tacrolimus as graft-versus-host disease prophylaxis. Forty-two percent of patients had a high or very high revised Disease Risk Index (rDRI), 55% had an European Society for Blood and Marrow Transplantation risk score (EBMT-RS) ≥4, and 36% had an age-adjusted Hematopoietic Cell Transplant Comorbidity Index (HCT-CI-age) score ≥3. Each of these was considered an unfavorable score. Using the pretransplantation unfavorable scores that had an independent impact on each transplantation outcome studied in multivariate analysis allowed for better stratification of patient outcomes. Thus, the 3-year overall survival (OS) in patients with 0, 1, 2, and 3 unfavorable scores was 86%, 56%, 36%, and 24%, respectively. Nonrelapse mortality (NRM) was negatively impacted by the EBMT-RS and the HCT-CI-age score (3-year NRM in patients with 0, 1, and 2 unfavorable scores was 12%, 33%, and 43%, respectively), whereas the EBMT-RS and the rDRI had an impact on the 3-year relapse incidence (8%, 18%, and 41% in patients with 0, 1, and 2 unfavorable scores, respectively). In conclusion, our study shows that combining 2 or 3 of these well-defined pretransplantation scores improves the ability to predict transplantation outcomes in the setting of haploSCT with PTCy.

Informe del Taller Ibérico de Histocompatibilidad 2013. Componente de análisis de situación de procedimiento de pruebas cruzadas en guardias de trasplante de órganos / Report of the 2013 Iberian Histocompatibility Workshop of 2013. Component analysis of the proceedings of cross-matching procedures in emergency organ transplantation

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Clinical relevance of pretransplant anti-HLA donor-specific antibodies: does C1q-fixation matter?

UNLABELLED: Anti-HLA donor-specific antibodies (DSA) identified by single antigen bead array (SAB) are questioned for their excess in sensitivity and lack of event prediction after transplantation. POPULATION AND METHODS: We retrospectively evaluated specific types of preformed DSA (class I, class II or C1q-fixing) and their impact on graft survival. Kidney transplantations performed across negative CDC-crossmatch were included (n=355). Anti-HLA antibodies were tested using SAB to identify DSA and their capacity to fix C1q. RESULTS: Twenty-eight patients with pretransplant DSA(+) with MFI>2000 were selected to assess C1q fixation. DSA were C1q+ in 15 patients and C1q- in 13, without significant differences in demographics, acute rejection, graft loss or renal function. The maximum MFI of DSA in patients with C1q-fixing DSA was significantly higher (p=0.008). Patients with DSA class-I suffered more antibody-mediated rejection (AMR) and had worse graft survival than class-II. The capacity of DSA I to fix C1q did not correlate with rejection, graft function or graft loss. CONCLUSIONS: C1q testing in pretransplant sera with DSA was unable to predict acute antibody-mediated rejection or early graft loss, but the presence of DSA class I compared to DSA only class II did. Despite non-fixing complement in vitro, pretransplant C1q-negative DSA I can mediate rejection and graft loss.

Alloimmune neonatal neutropenia and thrombocytopenia associated with maternal anti HNA-1a, HPA-3b and HLA antibodies.

The incidence of alloimmune neonatal neutropenia combined with neonatal alloimmune thrombocytopenia is very low. We report a case of a neonate who suffered severe neutropenia and thombocytopenia with widespread petechial spots. The presence of alloantibodies in mother's and patient's sera was analyzed by lymphocytotoxicity test, agglutination test, granulocyte indirect immunofluorescence test, platelet immunofluorescence test (PIFT) and solid phase enzyme-linked immunosorbent assay. Human neutrophil antigens (HNA) and human platelet antigen (HPA) genotypes were tested by polymerase chain reaction analyses. The mother's and patient's sera reacted with neutrophils and lymphocytes of the father. PIFT revealed the presence of IgG anti-platelet antibodies in the patient's serum but the test was negative in the maternal serum. Analyses of HNA-1 and HPA genotypes of the family revealed maternal-neonatal HNA-1a and HPA-3b mismatch. The study of the mother's and patient's sera showed the presence of anti HNA1a, HPA-3b and HLA antibodies specific for HLA-A3 and HLA-B38 antigens. These results suggest that the transplacental passage of maternal HNA-1a, HPA-3b and HLA alloantibodies caused neutropenia and thrombocytopenia in this patient.

Implication of CpG-ODN and reactive oxygen species in the inhibition of intracellular growth of Salmonella typhimurium in hepatocytes.

Bacterial DNA acts as an alert signal for eukaryotic cells through immunostimulatory CpG motifs. These sequences have therapeutic properties promoting protective immune TH1 responses and are recognized by a membrane protein belonging to the Toll-like receptor (TLR) family, named TLR-9. The aim of this study was to test the capability of murine hepatocytes to sense bacterial DNA and to develop antibacterial mechanisms against Salmonella typhimurium. We show that hepatocyte cell lines and mRNA extracts from murine liver constitutively express TLR-9, which is down-regulated by LPS and the mix of IFNgamma, IL-1beta and LPS. Also, we have found that hepatocyte cell lines can sense the presence of bacterial DNA and respond to it by increasing the pool of intracellular peroxides. This results in inhibition of intracellular growth of S. typhimurium when infected cells were incubated in the presence of CpG synthetic oligonucleotides (CpG-ODN). Expression of hepatocyte Mn-SOD is also induced by stimulation with CpG-oligodeoxynucleotides, LPS, and the mix of IFNgamma, IL-1beta and LPS. These results reinforce the prominent role of hepatocytes as a microbial product-responsive cell and the capabilities of CpG-ODN sequences as potent inducers of the innate immune response through the activation of a broad range of cell types.

HLA class II genotypic frequencies in atopic asthma: association of DRB1*01-DQB1*0501 genotype with Artemisia vulgaris allergic asthma.

Different human leukocyte antigen (HLA) class II alleles have been associated with the development of atopic asthma. To determine whether HLA class II alleles are associated with atopic asthma in a population from southeast Spain (Murcia region), 213 atopic asthmatic patients and 150 controls were selected for HLA typing. Significant association of the DRB1*01 and DQB1*0501 alleles was found in Artemisia vulgaris allergic patients (p(c) = 0.00052 and p(c) = 0.00023, respectively). No significant correlation was found in other atopic patients allergic to pollens (Phleum pratense, Olea europaea, and Salsola kali), house dust mites (Dermatophagoides pteronyssinus, D. farinae), molds (Alternaria alternata, Cladosporium herbarum), or animal danders (dog, cat). The results reveal that the DRB1*01-DQB1*0501 genotype is strongly associated with a positive response to Artemisia vulgaris in the population studied.

Human leukocyte antigen-C in short- and long-term liver graft acceptance.

In liver transplantation, rejection is still an important problem, and the role of human leukocyte antigens (HLA) has not been clearly established. At present, the possible involvement of HLA-C antigen in liver transplantation is still unexplored. The aim of this work was to analyze the influence of HLA-C polymorphism on the outcome of liver transplantation. For this purpose, genotyping of 100 orthotopic liver transplant recipient-donor pairs for HLA-C was performed with polymerase chain reaction-sequence-specific primers (PCR-SSPs). Liver recipients were stratified according to the occurrence of acute rejection. Patients without acute rejection were found to have a lower frequency of the HLA-Cw*06 allele compared with those with acute rejection or the control group. Moreover, when the role of HLA-C dimorphism was analyzed, natural killer (NK)1-alloantigens were found to be predominant in recipients without acute rejection. When the match of HLA-C single alleles and NK-alloantigens between donor and recipient was analyzed, it appeared that the frequency of acute rejection gradually decreased with decrease of the number of allele mismatches. Graft survival was increased when the number of mismatches in both HLA-C or NK-alloantigens was lower. In conclusion, the HLA-C locus may play a role in liver graft alloreactivity or allotolerance and, therefore, may be useful to avoid acute rejection and to achieve graft acceptance, resulting in a better final outcome in liver transplantation.

Flow cytometric quantification of apoptosis and proliferation in mixed lymphocyte culture.

BACKGROUND: The one-way mixed lymphocyte culture (MLC) is the classic culture used for studying the allogenic immunoresponse in vitro, but stimulator and responder cell identifications and quantification of apoptotic or proliferative responder cells are unreliable. METHODS: Peripheral blood mononuclear cells were labeled with 5- (and 6-) carboxy fluorescein diacetate succinimidyl ester (CFSE) and stimulated with allogenic unlabeled irradiated cells in unidirectional cultures. Apoptosis was determined by the 7-aminoactinomycin D technique, and the absolute number of each cell population was calculated by adding a fixed number of cells stained with propidium iodide as the reference standard for each test. RESULTS: CFSE labeling of cells under different cultures did not affect the results of proliferation or apoptosis. Data of apoptosis obtained with this method were comparable to those of the monoclonal antibody technique, and the proliferation level determined by [(3)H]-thymidine incorporation or counting the number of proliferative living cells, as proposed in this method, showed a good correlation. CONCLUSIONS: The method presented in this report allows the simultaneous determination of apoptosis and proliferation in MLCs and the analysis of cell phenotype, thereby avoiding the use of radioactivity. This assay opens new perspectives for a better understanding of the mechanisms implied in the establishment or break of tolerance to the graft in solid organ transplants.