The prognostic significance of HLA DR4 and B27 antigens was investigated in a 3-year follow-up of 87 patients with early rheumatoid arthritis (RA). The frequencies of DR1, DR4 and also of B27 were increased and the frequencies of DR2, DR3 and DR7 decreased compared with the normal Finnish population. During the follow-up with antirheumatic treatment, a similar improvement in clinical variables and laboratory measure assessing disease activity was found in both DR4-positive and DR4-negative RA patients. Despite clinical improvement a fast radiological progression in peripheral joints was observed but the presence of DR4 or B27 had no impact on the progression of joint damage. In some patients cervical changes developed early in the course of RA but were not related to DR4 or B27 positivity. The earlier observation of increased prevalence of HLA B27 in the Finnish RA patients was confirmed but the presence of B27 did not modify the clinical picture of RA.