title: Analysis of active and inactive complement C4 complotypes associated with subtypes of HLA-B17 in different racial groups.
abstract: HLA-A, B, and C antigens and the HLA-linked markers BF, C2, and C4 were determined in 1,799 unrelated Caucasians, 140 North American blacks, 140 Chinese, and 66 Japanese. One allele of the C4A locus (Rodgers), C4A*6, was found to code for a functionally inactive product in HLA-B17 (Bw57)-positive individuals, but for a functionally active product in HLA-B37- or HLA-B27-positive individuals. Further studies revealed that the functionally inactive C4A*6 gene product was found only in one subtype of HLA-B17, namely, 17.1 (Bw57, long). In addition, it was found that the frequency of the other subtype of HLA-B17, namely, 17.2(Bw58, short) varies greatly in different populations and that HLA-Bw58 is associated with either C4A*3,B*1 or C4A*3,B*Q0.
mesh_terms: D000483:Alleles; D003181:Complement C4 / Q000235:genetics* / Q000276:immunology; D005787:Gene Frequency; D014644:Genetic Variation; D006680:HLA Antigens / Q000235:genetics*; D006801:Humans; D007122:Immunoelectrophoresis; D010641:Phenotype; D044469:Racial Groups
chemical_list: D003181:Complement C4; D006680:HLA Antigens