[Multiple sclerosis in Northern-West region of Russia: results of HLA-typing].

Distribution of antigens of A, B, DR loci of HLA system in standard lymphocytotoxic test was studied in 59 patients with a significant diagnosis of multiple sclerosis (MS) and in 138 healthy donors. In the patients elevated frequency of the next antigens was found as compared with the controls: A10 (37%; chi 2 = 6.31; p < 0.05; relative risk--RR = 2.34), B7 (37%; chi 2 = 4.62; p < 0.05; RR = 2.05), B13 (29%; chi 2 = 10.86; p < 0.01; RR = 3.59), B35 (17%; chi 2 = 4.27; p < 0.05; RR = 2.61), DR2 (68%; chi 2 = 11.61; p < 0.001; RR = 2.99), as well as DR6 (5%; chi 2 = 3.95; p < 0.05; RR = 7.34) and also DRw52 (24%; chi 2 = 27.49; p < 0.001; RR = 21.16). The highest value of etiologic fraction was found for DR2 antigen. Analysis of intralocus and extralocus combinations of antigens in MS revealed that significantly elevated frequency had only one combination--B7DR2 (25.4%; chi 2 = 9.77; p < 0.01; RR = 3.58), relative risk was higher for this combination than for each individual antigen separately: B7 (RR = 2.05), DR2 (RR = 2.99). Significant negative associations with a possible protective effect of separate alleles were established in MS for antigens HLA A2 (34%; chi 2 = 5.55; p < 0.05; RR = 0.47), A11 (7%; chi 2 = 4.66; p < 0.05; RR = 0.31), A30 (0%; chi 2 = 4.50, p < 0.05; RR = 0.01), B18 (8%; chi 2 = 4.55; p < 0.05; RR = 0.35), DR5 (59%; chi 2 = 10.17; p < 0.01; RR = 0.36). The most significant was a decrease of the frequency of DR5 antigen (p < 0.01). Patients with the recurrent course had prevailed antigens A11, B21, B35 and decreased frequencies of antigens A9, B13, DR7. However, only the difference in the frequency of DR7 (16% in remitting and 57% in progredient course, chi 2 = 10.02; p < 0.001; RR = 0.14) was significant.