MOLECULAR ANALYSIS OF HLA-B27 HAPLOTYPES IN CAUCASOIDS - FREQUENCIES OF B27-CW IN JEWISH AND SPANISH POPULATIONS

PCR in combination with SSO probes was used to analyze the polymorphis m in exons 2 and 3 of HLA-B27 subtypes and HLA-C-related alleles in tw o genetically distant Caucasian groups: Spanish and Jewish populations . AS patients and healthy B27 donors from both populations were analyz ed in order to ascertain B27-Cw haplotypes. Three different ancestral haplotypes were found to be represented in both populations: B2705/ C w+0102, B2705/Cw*02022, and B*2702/Cw*02022. The B*2705 (92.5%) was t he most frequent allele found in the Spanish population, carried by B 2705/Cw0102 (60.9%) and B2705/Cw*02022 (30.4%) haplotypes. In contras t, B2702 (59.4%) was the most prevalent allele found in the Jewish po pulation and was carried by the B2702/Cw*02022 (63.3%) haplotype. No different allelic and haplotypic distributions were among healthy and AS patients in either Spanish or Jewish populations. The differences f ound in the distribution of B27 haplotypes among Spanish and Jewish Ca ucasian populations are consistent with the genetic distance of these ethnic groups. When the Jewish population was subdivided into Ashkenaz i (A) and non-Ashkenazi (NA) groups, no significant differences were o bserved in the distribution of B2702/Cw*02022 haplotype. Minor differ ences were observed in the underrepresented B2705 haplotypes. The pre sent results reflect the ancestral affinities of A and NA Jewish popul ations. A possible HLA-B27 evolutive pathway in Caucasians is proposed according to the data available for the B27/Cw ancestral haplotypes i n Spanish and Jewish groups.