OBJECTIVE: To investigate the prevalence of HLA-D region antigens in patients with seronegative rheumatoid arthritis (RA). METHODS: The distribution of HLA-D region antigens was studied in 33 patients with seronegative RA. All patients were followed for at least 3 years, during which tests for IgM rheumatoid factor were negative on at least 3 occasions. HLA-D region antigens were defined by serological and molecular techniques (oligonucleotide typing). RESULTS: Our data demonstrate that DR4 was significantly (p < 0.021) increased in patients (45.5%) compared to normal controls (22.9%). Although the prevalence of DR1 was essentially the same in patients (15.2%) as in healthy controls (14.3%), the frequency of DR1 and/or DR4 was significantly (p < 0.018) increased in patients (60.6%) compared to healthy subjects (35.7%). The prevalence of remaining DR antigens and of DQ and DP specificities in patients with seronegative RA was not different from that in healthy controls. CONCLUSION: Our results together with those published by other investigators suggest that both seropositive and seronegative RA are associated with DR4 and may therefore share the same immunogenetic bases.
OBJECTIVE: To investigate the prevalence of HLA-D region antigens in patients with seronegative rheumatoid arthritis (RA). METHODS: The distribution of HLA-D region antigens was studied in 33 patients with seronegative RA. All patients were followed for at least 3 years, during which tests for IgM rheumatoid factor were negative on at least 3 occasions. HLA-D region antigens were defined by serological and molecular techniques (oligonucleotide typing). RESULTS: Our data demonstrate that DR4 was significantly (p < 0.021) increased in patients (45.5%) compared to normal controls (22.9%). Although the prevalence of DR1 was essentially the same in patients (15.2%) as in healthy controls (14.3%), the frequency of DR1 and/or DR4 was significantly (p < 0.018) increased in patients (60.6%) compared to healthy subjects (35.7%). The prevalence of remaining DR antigens and of DQ and DP specificities in patients with seronegative RA was not different from that in healthy controls. CONCLUSION: Our results together with those published by other investigators suggest that both seropositive and seronegative RA are associated with DR4 and may therefore share the same immunogenetic bases.