THE ANTIGENIC DETERMINANTS, Rg/Ch/WH, EXPRESSED BY JAPANESE C4 ALLOTYPES

Abstract

SUMMARY The expression of antigenic determinants, Rg/Ch/WH, on Japanese C4 allotypes has been studied. Although the Japanese C4 allotype frequencies are known to differ from Europeans, the antigenic expression of their C4 allotypes correlates with associations described previously. All 89 random donors and 17 selected donors were Rg:1,2 so neither Rg:1,−2 nor Rg:−1,−2 was found. The frequency of Ch: 1,−2,3 was elevated while that of Ch: 1,2,3 was reduced, which was seen as a direct result of the higher frequency of B2 and B5 allotypes. None of the Japanese were Ch: 1,2,−3, but this can be accounted for by the absence of the A*6,B*1 haplotype. The WH determinant, which has been associated completely with Rg:1,−2 in Caucasians, was found at a higher frequency, 32%, in association with an A*3,2,B*QO haplotype expressing Rg:1,2, which has not been described previously. Detailed investigation showed that the A3 allotype was Rg:1,2 whereas the A2 allotype only expressed Rg1 (Rg:1,−2 WH+).

Complement C4A, C4B and BF haplotypes in Koreans

“…It is of interest that C4B*5 (0.073) have been observed more frequently in Mongoloid populations than in Caucasoid or Negroid populations (21,22). The duplication of C4A gene resulting in three or two expressed C4 genes (C4A*3+3 C4B*1, C4A*3+2 C4B*QO) per chromosome (1.9% in total), was assigned based on results from family studies at the protein level (6,9).…”

“…the C4A loci (C4A*3+3, C4A*3+2) and at the C4B loci (C4B*2+2, C4B"1+5, C4BZk 1+2) have been described (5)(6)(7)(8)(9)(10)(11). The polymorphism of BF has been studied on a large number of populations, and there are usually two common alleles (BF*F and BF*S), three less common alleles (BF*Fl, BF*S07 and BF"S04) and a number of rare alleles (12).…”

Two rare MHC haplotypes carrying DR2 in the Japanese population

“…One extended MHC haplotype carrying DRl5-DQ1, is the most common haplotype in Japanese, with a frequency 7-8% (6,7). This MHC haplotype, marked by the specific complement haplotype (complotype) C2C-BfS-C4A(3,2)-C4BQ0, carries two C4A genes, C4A3 and C4A2, but no C4B gene (8,9). The haplotype has been found not only in Japanese but also in Koreans, Northern Chinese and Mongolians (7,19).…”