COMPLEMENT C4A, C4B AND BF HAPLOTYPES IN KOREANS

Specific alleles at C4A, C4B and BF loci occur in populations and are inherited in complotypes, which are linked with particular HLA haploty pes. Considerable differences in complement allele and complotype freq uencies have been observed among various ethnic groups. In the present study, 109 Korean families were analyzed for complement and complotyp e polymorphism. Thirty-four different complotypes were detected: the m ost common was BFS-C4A*3-C4B*1 (S31) with a frequency of 42.2%, follo wed by S42 (14.3%) and F31 (13.8%). Three complotypes, S42, F31, and F Q01, showed positive linkage disequilibrium. Some of the complotypes w ere linked with characteristic HLA haplotypes. Two complotypes carryin g duplicated C4A genes, S3+31(BFS-C4A*3-C4A*3-C4B*1) and S3+2Q0(BF*S- C4A3-C4A*2-C4B*Q0), were exclusively associated with HLA-A24-Cw7-B7-D R1-DQ1 and A24-CBL-B52-DR15-DQ1 haplotypes, respectively. Twelve famil ies showed recombinant haplotypes, nine in the class I region, three b etween the HLA-B and HLA-DR loci, and none in the class III region. Ma ternal recombination occurred twice as frequently as paternal. The res ults obtained in this study represent the frequencies of complotypes a nd extended HLA haplotypes of well-defined Koreans, based on a family study.