Altered cellular immunity and suppressor cell activity in patients with primary retinitis pigmentosa.

A group of 54 patients with primary retinitis pigmentosa were studied and the following findings are described: response of lymphocytes to stimulation by phytohaemagglutinin (PHA); response of lymphocytes to stimulation by xenogenic retinal extract; distribution of T and T-active lymphoid populations; total suppressor activity induced by concanavalin-A (con-A). The results obtained showed a reduction in the response to PHA (p less than 0.05), a positive response of 26/45 (p less than 0.001) to stimulation by retinal extract, a reduction in the T and T-active lymphoid populations (p less than 0.01), (p less than 0.01), and a diminished total suppressor activity induced by con-A (p less than 0.01). This alterations of immune cellular responses and the diminished suppressor activity in the group of patients, in comparison with a control group of healthy subjects, seems to indicate the existence of an immune process of disregulation (autoimmunity?) in the pathology of primary retinitis pigmentosa.