43 patients (18 females, 25 males) presenting palindromic rheumatism were given follow-up examinations after a mean lapse of 14.75 years. 16 subjects still presented palindromic rheumatism and of these six showed complete remission. 27 patients had developed chronic inflammatory rheumatism after seven years (mean value) of palindromic rheumatism, but resolution of PR was seen in four cases. Male predominance was more marked in the palindromic subgroup (PAL) but was also seen in the subgroup of subjects who had developed PR (PAL-PR). Laboratory tests demonstrated a constant homogeneous increase in immunoglobulins (notable IgAs) and in the T4/T8 ratio in the PAL and PAL-PR subgroups. Rheumatoid serodiagnostic tests were positive significantly more frequently in the PAL-PR subgroup, which also comprised a high proportion of cases of erosive arthritis. Overall the frequency of HLA-DR 4 antigen did not increase in the subjects studied. Subjects in the PAL subgroup (cf. PAL-PR subgroup) were characterized by a twofold increase in frequency of DR 5 antigen, with a relative risk of 3.5 to 4.5, a significant increase in B35 and B5 and a clear decrease in B12.