[Physiopathology of rheumatoid psoriasis]

The physiopathology of rhumatoid psoriasis (RP) is poorly known. Besides the genetic factors we study immunological disorders from a series of 51 cases. We found mainly an increase of serum IgA, a decrease of IgM, a low level of circulating immune complexes, sometimes IgG type antiglobulin factor (very seldom IgM type, which explains the sero-negativity) seldom antinuclear antibodies; we found also a diminution of T lymphocytes detected by a decrease of E rosette - forming cells and an increase of the lymphocyte subpopulation forming high avidity EA rosettes, whereas the mitogenic response is normal or slightly decreased in the presence of Con A (not significant). A increased frequency of HLA DRW5 and DRW2 was found but too few cases were studied to make possible a definite conclusion. This immunopathologic profile is compared to that of psoriasis with anthropathy. The relevance of immune disorders in the physiopathology of RP is discussed.