HLA antigens in palindromic rheumatism, nonerosive rheumatoid arthritis and classical rheumatoid arthritis.

The frequency of HLA antigens has been investigated in patients with definite rheumatoid arthritis (RA) who lacked characteristic erosive radiographic changes that we called nonerosive rheumatoid arthritis ( NERA ). The frequency of HLA-DR4 in patients with NERA was significantly lower than that in classical, erosive RA. A normal frequency of HLA antigens was also found in patients with palindromic rheumatism (PR). Those of the PR patients who however, developed RA during followup, carried HLA-DR4. The patients with PR, NERA and RA who had familial RA demonstrated increased frequency of HLA-DR4.