HLA-DR ANTIGENS, GM ALLOTYPES AND ANTIALLOTYPES IN EARLY RHEUMATOID-ARTHRITIS - THEIR RELATION TO DISEASE PROGRESSION

Objective. Evaluation of the prognostic value of immunogenetic markers in early rheumatoid arthritis (RA). Methods. Ninety-nine patients wit h definite RA and disease duration 24 months or less were followed wit h standardized assessment. Disability was assessed by the HAQ index an d radiographic changes in hands and feet by the Larsen method. The fre quencies of HLA-DR genes were determined by serological typing, Gm all otype distribution by classical hemagglutination inhibition test, and occurrence of anti-Gm allotypes by use of anti-Rh coats. The immunogen etic findings were related to disease severity after 2 years' followup . Results. Functional capacity was well preserved, disease activity wa s less, but radiographic changes in hands and feet had increased consi derably at study finish. A group of 13 patients had developed rapidly progressive changes of hip and/or shoulder joints, all requiring arthr oplasty. There was a significantly increased frequency of HLA-DR4. Twe nty-seven of the 68 HLA-DR4 positive patients were putatively homozygo us. HLA-DR4 was not related to disability or to severe small joint des truction. However, progressive large joint damage was significantly mo re prevalent in homozygous patients (p < 0.01). Gm allotype distributi on was normal and not related to clinical findings. Anti-Gm antibodies were common and frequently specific for nonhost Gm allotype. Fifty-si x patients carried anti-G1m(a), and occurrence of this antibody was si gnificantly associated with radiographic progression of small joints ( p = 0.01), presence of nodules (p < 0.01) and number of active joints (p = O.OO1). Conclusion. Immunogenetic markers aided identifying patie nts with early RA with more severe disease.