Identification of a novel HLA-B allele, HLA-B*08:177, in a Hungarian patient and her HLA identical sibling.

The newly detected HLA-B*08:177 differs from HLA-B*08:01:01:01 by 1 single nucleotide substitution at position 365 of exon 3.

The potential role of HLA-DRB1*11 in the development and outcome of haematopoietic stem cell transplantation-associated thrombotic microangiopathy.

Transplantation-associated thrombotic microangiopathy (TA-TMA) is a serious complication of allogeneic haematopoietic stem cell transplantation (allo-HSCT) with high mortality rate. We retrospectively studied the frequency, clinical and genetic associations and prognostic effect of TA-TMA, in a total of 425 consecutive adult patients, who underwent allo-HSCT for a malignant haematological condition between 2007 and 2013 at our single centre. TA-TMA developed in 19% of the patients. Unrelated donor type (P<0.001), acute GvHD grades II-IV (P<0.001), myeloablative conditioning regimens (P=0.003), tacrolimus-based GvHD prophylaxis (P=0.003), CMV infection (P=0.003) and carriership for HLA-DRB1*11 (P=0.034) were associated with the development of TA-TMA. Survival was adversely affected by the presence of TA-TMA (P<0.001). Among patients with TA-TMA, the outcome of HLA-DRB1*11 carriers was significantly better compared with non-carriers (P=0.003). As a new finding, our observations suggest that the presence of HLA-DRB1*11 antigen contributes to the development of TA-TMA and affects the outcome.

HLA genetic diversity in Hungarians and Hungarian Gypsies: complementary differentiation patterns and demographic signals revealed by HLA-A, -B and -DRB1 in Central Europe.

Systematic analyses of human leukocyte antigen (HLA) profiles in different populations may increase the efficiency of bone marrow donor selection and help reconstructing human peopling history. We typed HLA-A, -B, and -DRB1 allele groups in two bone marrow donor cohorts of 2402 Hungarians and 186 Hungarian Gypsies and compared them with several Central-European, Spanish Gypsy, and Indian populations. Our results indicate that different European Gypsy populations share a common origin but diverged genetically as a consequence of founder effect and rapid genetic drift, whereas other European populations are related genetically in relation to geography. This study also suggests that while HLA-A accurately depicts the effects of genetic drift, HLA-B, and -DRB1 conserve more signatures of ancient population relationships, as a result of balancing selection.

Low occurrence of the HLA-C*04:09N allele in a large Hungarian cohort.

The presence of null alleles may affect the outcome of stem cell transplantation. HLA-C*04:09N was defined as 'common' with a frequency of 2-5/1000 in Caucasians, and its presence is routinely tested as part of haplotypes HLA-A*02:01/A*23:01-B*44:03-DRB1*07:01-DQB1*02:01. We aimed to investigate HLA-C*04:09N in a representative Hungarian cohort. HLA-typing data of 7345 unrelated persons were analyzed. The presence of HLA-C*04:09N was excluded in 157 chromosomes with either serology typing or with an allele-specific polymerase chain reaction for HLA-C*04:09N. HLA-C*04:09N was identified in a single chromosome with HLA-A*02, B*44, C*04, DRB1*07 resulting in a HLA-C*04:09N allele frequency of 0.0068% (1/14,690). This is approximately a 10- to 40-fold lower frequency compared with the previous data. Our results emphasize the need of precise local population-specific HLA-data, allowing appropriate modifications of local HLA-typing protocols.

Decrease in cold ischemic times as a result of protocol changes of urgent immunogenetic testing during cadaveric kidney transplantation in Hungary.

BACKGROUND: Based on national ethics committee permission, the procedure of urgent immunogenetics testing prior to cadaveric kidney transplantation was changed in Hungary from January 1, 2011 allowing HLA typing of the donor and prospective crossmatching using peripheral blood samples from the donor prior to the definitive declaration of brain death. The aim of the current study was to compare key indicators of transplantation primarily cold ischemic time [CIT], between time periods with outcomes. METHODS: The following indicators were systematically collected prospectively and retrospectively for each deceased heart-beating donor transplantation between January 1, 2010 and October 31, 2010 (n = 114) versus January 1, 2011 and October 31, 2011 (n = 91): CIT for the first and second kidney; laboratory turnaround times (TAT), and time for final preparation of the selected recipient. RESULTS: As a result of the new procedure, the CIT for the first kidney decreased from 16.5 ± 3.5 to 12.4 ± 3.2 hours (P < .001). Similarly, for the second kidney the parameters were a 19.8 ± 3.4 versus 16.0 ± 3.8 hours (P < .001). As a consequence of more hands-on time in the laboratory, the TAT increased from 5.6 ± 0.8 hours to 7.2 ± 1.1 hours (TAT1) followed by an additional 4.2 ± 1.0 hours (TAT2). We also compared the times necessary for preparation of immunologically suitable recipients for transplantation, namely, 9.5 ± 2.3 hours in the earlier system, increasing to 15.5 ± 4.3 hours during the new procedure. CONCLUSION: As a consequence of the procedural change, the CIT parameter decreased significantly for both kidneys, which may have contributed to improved short-term outcomes of transplantation. The time available for final preparation of selected recipients was increased allowing improvements in CIT.