SERONEGATIVE RHEUMATOID-ARTHRITIS AND HLA-DR4

Objective. To investigate the prevalence of HLA-D region antigens in p atients with seronegative rheumatoid arthritis (RA). Methods. The dist ribution of HLA-D region antigens was studied in 33 patients with sero negative RA. All patients were followed for at least 3 years, during w hich tests for IgM rheumatoid factor were negative on at least 3 occas ions. HLA-D region antigens were defined by serological and molecular techniques (oligonucleotide typing). Results. Our data demonstrate tha t DR4 was significantly (p < 0.021) increased in patients (45.5%) comp ared to normal controls (22.9%). Although the prevalence of DR1 was es sentially the same in patients (15.2%) as in healthy controls (14.3%), the frequency of DR1 and/or DR4 was significantly (p < 0.018) increas ed in patients (60.6%) compared to healthy subjects (35.7%). The preva lence of remaining DR antigens and of DQ and DP specificities in patie nts with seronegative RA was not different from that in healthy contro ls. Conclusion. Our results together with those published by other inv estigators suggest that both seropositive and seronegative RA are asso ciated with DR4 and may therefore share the same immunogenetic bases.