title: HLA class III haplotypes in multicase rheumatoid arthritis families.
abstract: The class III complement proteins (C2, BF, C4A, and C4B) were studied in 57 multicase rheumatoid arthritis (RA) families. When the gene frequencies for RA probands were compared to a normal control panel (162 haplotypes), a significantly higher frequency of the rare variant C4B*3 was observed (p less than 0.05). No significant differences were seen for the other C2, BF, C4A, or C4B alleles. The most common haplotype found in the probands was HLA-Cw5,B44,C2*C,BF*S,C4A*3,C4B*3,DR4, occurring with a frequency of 0.088. Haplotypes containing HLA-DR4 and Bw62 were found to carry either C4A*3,C4B*3; C4A*3,C4B*1; or C4A*4,C4B*2. When only haplotypes containing DR4 were compared between probands and controls, the frequency of the C4B*3-bearing haplotype remained higher in the probands. It is concluded that Bw62,C4A*3,C4B*3DR4 is a haplotype which is especially associated with RA. The low frequency in the RA population of this haplotype indicates that C4B*3 has a minor role in overall RA susceptibility.
authors.affiliation: Department of Immunology, Royal Postgraduate Medical School, London, England.
authors.forename: A H
authors.initials: AH
authors.lastname: Fielder
authors.forename: W
authors.initials: W
authors.lastname: Ollier
authors.forename: D K
authors.initials: DK
authors.lastname: Lord
authors.forename: M W
authors.initials: MW
authors.lastname: Burley
authors.forename: A
authors.initials: A
authors.lastname: Silman
authors.forename: J
authors.initials: J
authors.lastname: Awad
authors.forename: H
authors.initials: H
authors.lastname: Festenstein
authors.forename: J R
authors.initials: JR
authors.lastname: Batchelor
mesh_terms: D000483:Alleles; D001172:Arthritis, Rheumatoid / Q000235:genetics*; D003165:Complement System Proteins / Q000235:genetics*; D005787:Gene Frequency; D006680:HLA Antigens / Q000032:analysis; D006239:Haplotypes; D015395:Histocompatibility Antigens Class I / Q000032:analysis; D000949:Histocompatibility Antigens Class II / Q000032:analysis; D006801:Humans; D010375:Pedigree
chemical_list: D006680:HLA Antigens; D015395:Histocompatibility Antigens Class I; D000949:Histocompatibility Antigens Class II; D003165:Complement System Proteins