HLA DRB1 and HLA DQB1 Alleles in Bulgarian Patients with Primary and Secondary Antiphospholipid Syndrome

Antiphospholipid syndrome (APS) is an autoimmune disease with multifactorial and polygenic pathogenesis. Recently, the genetic predisposition in APS has been subjected to wide discussion. The aim of this study is to determine the prevalence of DRB1 and DQB1 loci in Bulgarian population of healthy persons and patients with primary (PAPS) and secondary (SAPS) APS. Patients are divided in 5 groups: I-29 patents with systemic lupus erythematosus (SLE) with SAPS, II-35 patients with PAPS, III-32 women with spontaneous abortions without aPL, IV-15 patients with different thrombosis (deep venous thromboses, pulmonary embolism, mesenterial thrombosis, myocardial infarction, stroke) without laboratory data for APS, and V-16 SLE patients without clinical and laboratory data for APS. SAPS patients have more frequently DRB1*03 and DQB1*02 and more rarely DRB1*11 and DQB1*03 in comparison with healthy subjects and patients with PAPS. Patents with PAPS, those with spontaneous abortions and patients with thrombotic events but without antiphospholipid antibodies (aPL) have DRB1*03, DRB1*11, DQB1*02 and DQB1*03 alleles similar to the general population. There are no differences between group I (SLE+APS) and group V (SLE) in DRB1* and DQB1*alleles.