Transformation from SAA2-fibrils to AA-fibrils in amyloid fibrillogenesis: in vivo observations in murine spleen using anti-SAA and anti-AA antibodies

PCR in combination with SSO probes was used to analyze the polymorphism in exons 2 and 3 of HLA-B27 subtypes and HLA-C-related alleles in two genetically distant Caucasian groups: Spanish and Jewish populations. AS patients and healthy B27 donors from both populations were analyzed in order to ascertain B27-Cw haplotypes. Three different ancestral haplotypes were found to be represented in both populations: B*2705/Cw*0102, B*2705/Cw*02022, and B*2702/Cw*02022. The B*2705 (92.5%) was the most frequent allele found in the Spanish population, carried by B*2705/Cw*0102 (60.9%) and B2705/Cw*02022 (30.4%) haplotypes. In contrast, B*2702 (59.4%) was the most prevalent allele found in the Jewish population and was carried by the B*2702/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 found in the distribution of B27 haplotypes among Spanish and Jewish Caucasian populations are consistent with the genetic distance of these ethnic groups. When the Jewish population was subdivided into Ashkenazi (A) and non-Ashkenazi (NA) groups, no significant differences were observed in the distribution of B*2702/Cw*02022 haplotype. Minor differences were observed in the underrepresented B*2705 haplotypes. The present results reflect the ancestral affinities of A and NA Jewish populations. A possible HLA-B27 evolutive pathway in Caucasians is proposed according to the data available for the B27/Cw ancestral haplotypes in Spanish and Jewish groups.