Association ofcomplement alleles C4AQO and C4B5withrheumatoid arthritis inKoreans

Objective-To investigate theassociation ofcomplement C4allotypes withrheumatoidarthritis inKoreans. Methods-65rheumatoidarthritis patients and255controls weretypedforC4 allotypes andHLA-A,B,C,DR,andDQ antigens. Results-The frequencies ofC4AQ0 (32.3% v14.90/., P <0.005) andC4B5(29.2% v12.2%, P < 0.005) weresignificantly increased in rheumatoid arthritis patients compared withhealthycontrolsubjects. Among rheumatoid patients, thefrequency of C4AQOwassignificantly increased inboth the rheumatoidfactor(RF) positive (27.3%)and theRF negative (66.7%) subgroups. Thefrequencies ofC4B5and HLA-DR4 were significantly increased onlyinRF positive subgroup. C4B5was stronglyassociated with HLA-DR4, whereasC4AQOdidnotshowassociation withDR4. Conclusions-In Koreans,C4AQO and C4B5areassociated withsusceptibility to rheumatoid arthritis, asintheJapanese. C4B5isstrongly associated withHLADR4.C4AQOisconsidered tobea DR4 independent riskfactor, andadisease susceptibility allele inlinkage disequilibrium withC4AQO issuggested in Korean patients withrheumatoid arthritis. (AnnRheumDis1996;55:776-778)