Severe aplastic anemia (SAA) is a heterogeneous hematological disorder with a high mortality. Genetic predisposition has been shown to play a role in a considerable proportion of SAA cases. For instance, the human lymphocyte antigen HLA-DR2 has been repeatedly demonstrated to be over-represented in SAA patients. In this paper, we expand on the evidence for the contribution of HLA polymorphism in the susceptibility to SAA, which was obtained using the "high-resolution" technique of HLA-DRB1 subtyping. The DRB1*1501 allele appeared to be responsible for the predominance of DR2 specificity in SAA patients and was the most significant risk factor for this disease. It was observed in 23/44 (52.3%) patients versus 22/100 (22.0%) donors [odds ratio (OR) = 3.9; 95% confidence interval (CI): 1.8-8.3; P = 0.0005, corrected P (Pc) < 0.05]. In addition, DRB1*04 alleles also displayed non-random distribution in the SAA group. In particular, DRB1*04 variants coding for alanine at position 74 of the DR beta 1 chain (HLA-DR4-Ala74 beta subtype) were detected in all 13 DR4-positive SAA patients but only in 15/24 (62.5%) controls (OR = 16.6; 95% CI: 0.9-312.0; P = 0.015). Multiple comparison analysis confirmed that the HLA-DR4-Ala74 beta subtype confers susceptibility to SAA independently from the DRB1*1501 allele. Finally, examination of the clinical records has shown that the HLA-DR4-Ala74 beta subtype is associated with poor outcome of SAA.

The association between severe aplastic anemia (AA) and DR2 antigen seems to be well established. However, since discrimination between two DR2-associated splits, namely DR15 and DR16, rarely was performed, it remains unclear whether one or both of these subvariants are responsible for AA susceptibility. In this study, we have analyzed the HLA-DR allelic distribution in a group of 37 AA patients of slavic origin from North-Western Russia. The experimental design included PCR-based amplification of DRB-specific sequences, followed by reverse dot-blot hybridization of the biotinylated PCR-product with the set of sequence-specific oligonucleotide probes. HLA-DRB alleles were identified by non-radioactive enzymatic reaction, then standard serological specificities of HLA-DR antigen were estimated according to the WHO nomenclature. Whereas DR15 subtype occurred more often in the patients (23.0% vs. 13.3%, p< 0.05), DR16 split did not show the same tendency. The results, show the overall predominance of HLA-DR2 specificity (DR15+DR16) did not reach statistical significance (24.4% vs.17.5%, p<0.2). Thus, we conclude that repeatedly reported DR2 frequency increase in AA patients is mainly attributed to the prevalence of DR15 subtype.

Федеральное государственное бюджетное образовательное учреждение высшего образования «Московский государственный медикостоматологический университет имени А.И. Евдокимова» Министерства здравоохранения Российской Федерации, 127473, г. Москва, Российская Федерация 2 Государственное бюджетное учреждение здравоохранения «Инфекционная клиническая больница № 2» Департамента здравоохранения г. Москвы,

Bernard-Soulier disease, a congenital macrocytic thrombocytopathy, was first described in 1948. Currently, this pathology has again attracted the attention of many researchers, as the study of its pathogenesis has deepened the understanding of the mechanisms of the hemostatic process concerning the interaction of platelets with the damaged vessel wall. This rare disease (70 cases were described by 1983) is inherited as an incomplete autosomal recessive trait and is observed with equal frequency in males and females. Bleeding from mucous membranes of the nose, mouth and other organs, petechiae and ecchymoses on the skin usually appear in early childhood. Hemorrhagic syndrome is usually of moderate severity, but often (in 17% of patients) is the direct cause of death due to bleeding from the gastrointestinal tract or hemorrhage in the brain and its membranes.