A catalog of common, intermediate and well‐documented (CIWD) HLA‐A, ‐B, ‐C, ‐DRB1, ‐DRB3, ‐DRB4, ‐DRB5, ‐DQB1 and ‐DPB1 alleles has been compiled from over 8 million individuals using data from 20 unrelated hematopoietic stem cell volunteer donor registries. Individuals are divided into seven geographic/ancestral/ethnic groups and data are summarized for each group and for the total population. P (two‐field) and G group assignments are divided into one of four frequency categories: common (≥1 in 10 000), intermediate (≥1 in 100 000), well‐documented (≥5 occurrences) or not‐CIWD. Overall 26% of alleles in IPD‐IMGT/HLA version 3.31.0 at P group resolution fall into the three CIWD categories. The two‐field catalog includes 18% (n = 545) common, 17% (n = 513) intermediate, and 65% (n = 1997) well‐documented alleles. Full‐field allele frequency data are provided but are limited in value by the variations in resolution used by the registries. A recommended CIWD list is based on the most frequent category in the total or any of the seven geographic/ancestral/ethnic groups. Data are also provided so users can compile a catalog specific to the population groups that they serve. Comparisons are made to three previous CWD reports representing more limited population groups. This catalog, CIWD version 3.0.0, is a step closer to the collection of global HLA frequencies and to a clearer view of HLA diversity in the human population as a whole.
Recombinant human erythropoietin (r-HuEpo) has been used for the treatment of renal anemia. With the loss of its patent protection, there has been an upsurge of more affordable biosimilar agents, increasing patient access to treatment for these conditions. The complexity of the manufacturing process for these recombinant proteins, however, can result in altered properties that may significantly affect patient safety. As it is not known whether various r-HuEpo products can be safely interchanged, we studied 30 patients with chronic kidney disease treated by subcutaneous injection with biosimilar r-HuEpo and who developed a sudden loss of efficacy. Sera from 23 of these patients were positive for r-HuEpo-neutralizing antibodies, and their bone marrow biopsies indicated pure red-cell aplasia, indicating the loss of erythroblasts. Sera and bone marrow biopsies from the remaining seven patients were negative for anti-r-HuEpo antibodies and red-cell aplasia, respectively. The cause for r-HuEpo hyporesponsiveness was occult gastrointestinal bleeding. Thus, subcutaneous injection of biosimilar r-HuEpo can cause adverse immunological effects. A large, long-term, pharmacovigilance study is necessary to monitor and ensure patient safety for these agents.
An international collaborative study of 45 transplant centers was undertaken at the 14th International HLA (human leukocyte antigen) and Immunogenetics Workshop to see if HLA antibodies detected posttransplant are predictive of chronic graft failure. With the newly developed assay, MICA (major histocompatibility complex class I-related chain A) antibodies were also measured and their effect analyzed. Total of 5219 sera from patients who were more than 6 months posttransplant with functioning graft were tested for HLA antibodies by enzyme-linked immunosorbent assay, flow cytometry, or Luminex. HLA antibodies were found in 27.2% of kidney patients, 23.6% in the liver, 52.7% in the heart, and 21.7% in the lung. The method of antibody testing did not have a marked influence on the frequency of antibodies detected. MICA antibodies were detected in 15% of kidney patients, 30% of heart patients, and 31% of liver patients. Among 948 kidney patients who had HLA antibodies, 7.3% had rejected their graft within 1 year of testing, compared with 1.7% in 2615 patients without HLA antibodies (P= 0.8 x 10(-17)). Death occurred in 1.4% of total kidney patients and did not correlate to the presence of antibodies. We conclude that patients with posttransplant HLA antibodies indeed have a higher rate of chronic graft failure and that posttransplant antibodies are predictive of chronic rejection.
The Ata blood group antigen (now AUG2 in the Augustine system) is a high‐frequency antigen with negative phenotype At(a−) found only in individuals of African ancestry. In a twin pregnancy, the fifth pregnancy in a woman of African origin, serological investigations confirmed that the mother was At(a−) and anti‐Ata was detected. DNA samples were exome sequenced and alignment was performed to allow variant calling. It was confirmed that the single nucleotide polymorphism, rs45458701, within the SLC29A1 gene encoding the ENT1 protein, recently reported to be a basis of the At(a−) phenotype was also the basis of the phenotype in this family. The reagents for serological analysis required to identify the rare blood type present in this mother are held in only a few reference laboratories worldwide. This case highlights the utility of genetic methods in resolving complex investigations involving blood grouping and demonstrates that genotyping of variants associated with blood types present in specific ethnic groups may be the fastest method available for identification of the basis of fetomaternal incompatibilities.
Pegfilgrastim is produced by binding a 20,000-dalton polyethylene glycol molecule to granulocyte colony-stimulating factor (G-CSF), increasing the mass of the compound, and resulting in a longer-lasting form of G-CSF. This makes it more convenient to use pegfilgrastim as a single-day injection. This study was a prospective phase II single-center trial. Fifteen normal related donors received pegfilgrastim 12 mg subcutaneously to mobilize peripheral blood stem cells (PBSC) for allogeneic stem cell transplantation. Leukapheresis was planned to start 3 days after injection. All harvests were successful. Median number of leukapheresis was 2 days (range 1-3 days). There were 7/15 donors who only required single leukapheresis. The maximum concentration of white blood cells (WBC) and circulating CD34 cells occurred 3 days after pegfilgrastim injection (WBC: median 62,200/μl; CD34: median 69.76/μl). The median yield of CD34 cells was 6.78 × 10(6)/kg recipient weight. The median CD3 cells was 1.89 × 10(8)/kg recipient weight. The main adverse events were bone pain and headache. Median neutrophil and platelet engraftments in the recipients occurred on day 12 and day 13, respectively, after transplantation. PBSC mobilization with single-day injection of pegfilgrastim in normal donor is feasible. Further comparisons of this protocol to standard G-CSF for allogeneic stem cell mobilization should be conducted in future.
Our data demonstrated the association of HLA-DRB1*09-DQB1*0309 and anti-r-HuEpo associated PRCA cases. This association may be used in identifying the risk of the patients.
BackgroundDuffy (FY) blood group genotyping is important in transfusion medicine because Duffy alloantibodies are associated with delayed hemolytic transfusion reactions and hemolytic disease of the fetus and newborn. In this study, FY allele frequencies in Thai blood donors were determined by in-house PCR with sequence-specific primers (PCR-SSP), and the probability of obtaining compatible blood for alloimmunized patients was assessed.MethodsFive hundred blood samples from Thai blood donors of the National Blood Centre, Thai Red Cross Society, were included. Only 200 samples were tested with anti-Fya and anti-Fyb using the gel technique. All 500 samples and four samples from a Guinea family with the Fy(a-b-) phenotype were genotyped by using PCR-SSP. Additionally, the probability of obtaining antigen-negative red blood cells (RBCs) for alloimmunized patients was calculated according to the estimated FY allele frequencies.ResultsThe FY phenotyping and genotyping results were in 100% concordance. The allele frequencies of FY*A and FY*B in 500 central Thais were 0.962 (962/1,000) and 0.038 (38/1,000), respectively. Although the Fy(a-b-) phenotype was not observed in this study, FY*BES/FY*BES was identified by PCR-SSP in the Guinea family and was confirmed by DNA sequencing.ConclusionsOur results confirm the high frequency of the FY*A allele in the Thai population, similar to that of Asian populations. At least 500 Thai blood donors are needed to obtain two units of antigen-negative RBCs for the Fy(a-b+) phenotype.
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