HLA DRB1-ASTERISK ALLELES IN RHEUMATOID NODULOSIS - A COMPARATIVE-STUDY WITH RHEUMATOID-ARTHRITIS WITH AND WITHOUT NODULES

Rheumatoid nodulosis (RN) is a rare condition associating rheumatoid n odules, episodes of arthritis, cystic bone lesions and, generally, pos itive rheumatoid factors (RF). It is considered a benign variant of rh eumatoid arthritis (RA). In this study, we determined the HLA DRB 1 a lleles of our RN patients and compared the distribution of these allel es to those of 74 healthy controls and 104 RA patients with and withou t nodules. Four RN patients were observed. All had subcutaneous nodule s and RF were negative in three patients. Of the 104 RA patients, 18 h ad nodules (nodRA). Systemic manifestation (including vasculitis, peri pheral neuropathy or lung involvement) were found in seven of these no dRA cases (33.8%) and most had positive RF and erosive changes on X-ra ys. Only one RN patient had a RA-associated allele (DRB 10101). The f requencies of the HLA DRB1 alleles encompassing the ''rheumatoid'' sh ared epitope were similar to those of other RA series: 0101, 34.6% (P =0.03 compared with controls); 0401, 26.9% (P<0.0001); *0404, 12.5% ( P=0.04); 0405, 4.8% (P=0.8); *1001, 8.6% (P=0.5), Of the nodRA and se ronegative RA patients, 77.7% and 53.3%, respectively, presented the s hared epitope. Thus, there was a tendency to decreased expression of t he RA-associated alleles in RN (25%) compared with nodRA and seronegat ive RA patients. This study is restricted by the small number of teste d RN patients, but the results suggest that the RA-associated alleles are poorly expressed in RN.