HLA CLASS-II AND HLA-B27 OLIGOTYPING IN 2 SIBERIAN NATIVE POPULATION GROUPS

It was the purpose of this study to better define the frequency of HLA -B27 subtypes and HLA class II alleles among indigenous populations fr om the eastern tip of the Chukotka Peninsula of Siberia, Russia, which have higher frequencies of HLA-B27 (40%) and spondyloarthropathies (2 %) than Caucasian populations and test the hypothesis that these popul ations are more closely related to Orientals. Siberian Eskimos and Chu kchi residing in four coastal villages on the Chukotka Peninsula inhab ited by Siberian Eskimos and Chukchi people were examined using oligot yping of the polymerase-chain reaction-amplified second and third exon s of the HLA-B27 gene. HLA-class II alleles (DRB1, DQA1 and DQB1) were similarly determined. Of 88 HLA-B27 positive individuals from these v illages, all had HLA-B2705, including the four patients with Reiter's syndrome and the five ankylosing spondylitis, except one Eskimo contr ol who had HLA-B2702. None had HLA-B*2704, a frequent subtype in Orie ntals. HLA-class II typing in 70 Siberian Eskimos and 71 Siberian coas tal Chukchi revealed HLA-DRB10401, DRB1* 0802, *0901 and *1402 to acc ount for nearly all the DRB1 alleles found in this population, similar to what has been described in Eskimos in Alaska, but different from C hinese or native Americans in the U.S. The overwhelming majority of th e individuals examined had HLA-DQB10301, similar to what has been obs erved in Native Americans. The Siberian Eskimos differed from the coas tal Chukchi only in the occurrence of HLA-DRB10701, DQA1*0201, DQB1*0 201 alleles, which occurred only in the former group. These data sugge st that the Chukotka population is genetically more closely related to Caucasians and native Americans and less to other Oriental population s.