Donor-Specific Anti-HLA Antibodies in Haploidentical Stem Cell Transplantation with Post-Transplantation Cyclophosphamide: Risk of Graft Failure, Poor Graft Function, and Impact on Outcomes.

The presence of donor-specific anti-HLA antibodies (DSA) is associated with a 10-fold increased risk of graft failure in haploidentical stem cell transplantation (haplo-SCT). Consensus guidelines from the European Society for Blood and Marrow Transplantation set a mean fluorescence intensity (MFI) >1000 as a cutoff for DSA positivity. In the absence of an alternative donor, it is recommended that patients undergo desensitization therapy, especially with high DSA levels (>5000 MFI). The aim of this study was to analyze the impact of DSA on risk of graft failure and poor graft function, as well as on major outcomes in a consecutive cohort of patients who were systematically screened for DSA before haplo-SCT. A total of 141 consecutive patients were candidates for unmanipulated haplo-SCT with post-transplantation cyclophosphamide (PT-Cy) at our center between January 2012 and January 2018, and 135 were analyzed for the presence of HLA antibodies. Of these 134 patients underwent haplo-SCT. HLA antibodies were detected in 40 patients, including 19 with DSA and 21 without DSA. Ten of the 19 patients with DSA underwent transplantation using that donor, whereas 2 underwent a desensitization program before transplantation. Only 2 patients experienced primary graft failure (1.4 %), both of whom were without DSA. Twenty patients developed a poor graft function (15%). The 3-year overall survival (OS), 3-year progression-free survival (PFS), and 1-year nonrelapse mortality (NRM) were analyzed according to the presence or absence of DSA. No statistically significant difference was found. No impact of the presence of DSA on the risk of developing graft failure and poor graft function was revealed. Major outcomes of transplantation were analyzed separately in patients with poor graft function and those with good graft function. The 3-year OS, 3-year PFS, and 1-year NRM in good graft function and poor graft function populations were 62% versus 20% (P < .0001), 53% versus 20% (P < .0001), and 12% versus 40% (P = .009), respectively. The presence of low-level DSA in the absence of desensitization did not correlate with the risk of developing graft failure and poor graft function. Patients who experienced poor graft function had worse outcomes than patients with good graft function.

A Microsphere-Based Suspension Array for Blood Group Molecular Typing: An Update.

SUMMARY: BACKGROUND: In a previous publication we described a method for Jk(a)/Jk(b), Fy(a)/Fy(b), S/s, K/k, Kp(a)/Kp(b), Js(a)/Js(b), Co(a)/Co(b), and Lu(a)/Lu(b) genotyping based on a microsphere suspension array. Here, an improved version of the assay is presented. METHODS: TWO MULTIPLEX POLYMERASE CHAIN REACTIONS (PCR) WERE DEVELOPED: one for amplification of samples routinely tested and the other for those systems that are tested less frequently. Each biotinylated PCR product is hybridized in a single multiplex assay. A total of 2,020 samples were analyzed, and the genotypes were compared to the blood group phenotypes. RESULTS: There have been no discrepancies with the serology results other than null and/or weak phenotypes. CONCLUSION: In its present form, the method presented here has the capacity to genotype hundreds of a samples in few hours with a high concordance rate with serology.

Complete sequencing of the HLA-A*68020102 novel allele identified in two Caucasoid families.

We describe here the isolation and the full-length sequence of the coding region of the HLA new variant at the HLA-A locus officially named A*68020102. This variant shows an 11 base pairs deletion within the 5' UTR region. The exon sequence is identical to that of A*6802 and the commercially available anti-A68 typing sera react with the antigen coded by the allele A*68020102. This variant was originally identified in two unrelated Caucasoid families because of discrepant HLA typing results between serology, Sequence Specific Oligonucleotide Probe (SSOP), and SBT. In fact, the A68 assigned by serology was undetectable with the molecular techniques. This has occurred because the deletion present in A*68020102 prevents specific amplification of HLA-A locus by some commercially available typing kits.

Isoniazid in patient plasma may cause a false-positive result on the complement-dependent cytotoxicity test.

Correct definition of clinically relevant anti-HLA antibodies is important for transplant organ allocation and outcome. We describe a candidate for kidney transplantation who was treated with isoniazid because of active tuberculosis. The patient's serum gave a positive antibody result on screening with the complement-dependent cytotoxicity (CDC) test but a negative result on screening with a bead-based assay (Luminex). The clinical history indicated no immunologic stimuli. Subsequent testing on fresh serum samples confirmed the discrepancy between CDC and Luminex results. An autologous cross-match test gave negative results, and the antibodies were sensitive to dithiothreitol treatment. We postulated that nonspecific binding of drug-antibody complexes to panel lymphocytes in the CDC test may have caused the observed lympholysis. This case, although isolated, emphasizes the importance of the combined use of CDC and solid phase assays. The CDC results alone would have led to the erroneous conclusion that the patient was highly sensitized.

Blood group genotyping for Jk(a)/Jk(b), Fy(a)/Fy(b), S/s, K/k, Kp(a)/Kp(b), Js(a)/Js(b), Co(a)/Co(b), and Lu(a)/Lu(b) with microarray beads.

BACKGROUND: Traditionally, blood group typing has been performed with serologic techniques, the classical method being the hemagglutination test. Serotyping, however, may present important limitations such as scarce availability of rare antisera, typing of recently transfused patients, and those with a positive direct antiglobulin test. Consequently, serologic tests are being complemented with molecular methods. The aim of this study was to develop a low-cost, high-throughput method for large-scale genotyping of red blood cells (RBCs). STUDY DESIGN AND METHODS: Single-nucleotide polymorphisms associated with some clinically important blood group antigens, as well as with certain rare blood antigens, were evaluated: Jk(a)/Jk(b), Fy(a)/Fy(b), S/s, K/k, Kp(a)/Kp(b), Js(a)/Js(b), Co(a)/Co(b), and Lu(a)/Lu(b). Polymerase chain reaction (PCR)-amplified targets were detected by direct hybridization to microspheres coupled to allele-specific oligonucleotides. Cutoff values for each genotype were established with phenotyped and/or genotyped samples. RESULTS: The method was validated with a blind panel of 92 blood donor samples. The results were fully concordant with those provided by hemagglutination assays and/or sequence-specific primer (SSP)-PCR. The method was subsequently evaluated with approximately 800 blood donor and patient samples. CONCLUSION: This study presents a flexible, quick, and economical method for complete genotyping of large donor cohorts for RBC alleles.

Flow-cytometric approach to the prompt laboratory diagnosis of TRALI: a case report.

OBJECTIVES: Transfusion-related acute lung injury (TRALI) is a rare but serious complication which can occur after transfusion of blood components. In this report we describe our flow-cytometry approach to the laboratory diagnosis of a case of TRALI in a recipient of fresh frozen plasma containing human leukocyte antigen (HLA) class II antibodies. METHODS: The post-transfusion reaction work-up included the direct and indirect Granulocyte Immunofluorescence Test (GIFT) on the recipient's neutrophils collected before and after the reaction and on the serum from the recipient and from all implicated donors; flow-cytometry bead-based screening and identification assay for HLA class I and II antibodies in donor sera and flow cytometry cross-matching on T and B patient's lymphocytes. Finally, we investigated the reactivity of one donor serum, containing HLA class II antibodies, with the patient's neutrophils activated in vitro to induce expression of HLA class II. RESULTS: We found an increased level of IgG bound on patient's granulocytes collected after TRALI, in the absence of detectable granulocyte and HLA class I antibodies in the five implicated donors. One of them showed HLA-DR 1 and -DR 51 antibodies, which determined a positive cross-match with patient's B lymphocytes and in vitro activated granulocytes. Both HLA class II antigens were present in the recipient and absent in the donor. CONCLUSIONS: In some pathological conditions, HLA class II antibodies can react with activated granulocytes expressing HLA-DR antigens, and activate TRALI reaction. HLA class II antibodies screening and flow cytometry cross-matching techniques should be added to the current diagnostic algorithm of TRALI.