engleski

The diversity of HLA-B27 alleles in Croatians and their associations with HLA-A and -Cw alleles

The HLA-B27 serologic specificity represents a family of 23 closely related alleles that differ in a restricted number of nucleotides which are mostly located in exons 2 and 3. The frequency of HLA-B27 antigen in the Croatian population is around 10%. The aim of this study was to investigate the distribution of B27 alleles and B27 haplotypic associations in the Croatian population. For that purpose we have studied 156 healthy, unrelated inhabitants of Zagreb, originated from different regions of Croatia. All individuals were tested for HLA-A, and -B loci by PCR-RLS (Reverse Line Strip) which was official method for anthropology component of the 13th International Histocompatibility Workshop (13thIHW). HLA-Cw locus was tested using PCR-SSP method. Molecular analysis showed that among 156 individuals, 18 were positive for B*27 (5.8%). Between twelve B27 alleles detectable with this method, B*2705 was predominate allele in our population (61.1%). Allele B*2702 was present with frequency of 27.8%, while B*2704 was observed in two individuals (11.1%). Among B*2705 haplotypic associations, A*0201-B*2705 (40.9%, LD=1.3) and A*2402-B*2705 (22.7%, LD=0.7) were most frequent. In the group of B*2702 associations, four out of five were combination A*2402-B*2702. Two different Cw alleles were observed in association with B*27 subtypes: Cw*0102 and Cw*0202. The B*2705 was found in combination with both Cw alleles, 7 out of 11 were with Cw*0202, while the other four were with Cw*0102. On the other hand, B*2702 was associated only with Cw*0202. Comparison of results between our and other populations so far reported did not reveal significant differences. These results will help for studying diversity of B27 alleles and haplotypic associations in the world and will also serve as reference for further B27 disease association studies. It is also important to mention that more extensive molecular typing of the Croatian population will be necessary to prove our findings.

HLA-B27; HLA-A; -Cw; haplotypic associations; Croatians

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