HLA FREQUENCIES IN HLA-B27 NEGATIVE PATIENTS WITH REACTIVE ARTHRITIS

The purpose of the present work was to find out whether there is an HL A type common to the patients who, in spite of being B27 negative, hav e developed reactive arthritis (ReA). We compared the HLA-antigens of 25 HLA-B27 negative ReA patients to those of healthy control persons. No statistically significant differences were observed in the HLA-A, B , C, DR and De antigen frequencies between the patients and the contro l group. The frequency of DR4 was slightly lower in. the patients than in the cona ols, although this difference was not statistically signi ficant. On the other hand, 18/25 (72%) of the B27-negative ReA patient s experienced a chronic or prolonged course of the disease. These find ings indicate that DR4 does not contribute to the chronicity of ReA in the same way that it is known to do in rheumatoid arthritis (RA) or L yme arthritis. They do not support the hypothesis that some other HLA- antigen, in addition to HLA-B27, could have a predisposing or protecti ve effect in ReA.