The effect of HLA-DRB1 genes, rheumatoid factor, and treatment on radiographic disease progression in rheumatoid arthritis over 6 years

Objective. To investigate the relationship between radiographic disease pro gression in the presence or absence of rheumatoid arthritis (RA) linked HLA -DRB1 alleles after early introduction of disease modifying antirheumatic d rug therapy in patients with RA over a study period of 6 years. Methods. One hundred nine patients of a trial comparing intramuscular(im) g old sodium thiomalate (GSTM) and im methotrexate (MTX) in early erosive RA were followed for 6 years with regular assessments of clinical and laborato ry data and yearly radiographs of hands and feet, and they were typed for H LA-DRB1 genes. Radiographic progression was analyzed for an influence of rh eumatoid factor (RF) status and HLA-DRB1 genes. Results. Twenty-seven patients (25%) were positive for two. 46 (42%) for on e, and 36 (33%) for none of the disease linked alleles. A decrease of the r ate of radiographic disease progression with treatment in this group of pat ients was reflected by the decline in the slope of the radiographic score. Seropositive patients (n = 71, 68%) had a significantly more destructive di sease course than RF negative patients. In seropositive disease, patients w ith a "double dose" of RA linked alleles showed a tendency to greater progr ession during the First 12-24 mo of treatment. but no significant differenc e in the longterm radiographic outcome could be detected between subgroups defined by the presence or absence of HLA-DRB1 genes. There was no signific ant difference throughout the study period with respect to the clinical dis ease course as assessed by joint swelling, C-reactive protein, and erythroc yte sedimentation rate. The majority of the seronegative population (n = 38 , 32%) had a benign disease course with the exception of patients (n = 6) w ith the double allele; they had radiographic disease progression comparable with the seropositive patients. Conclusion. Our data do not provide evidence fur a more aggressive disease course in patients bearing double RA linked HLA-DRB1 alleles.