Interleukin-10 receptor expression in systemic lupus erythematosus and rheumatoid arthritis

Objective. We aimed to determine the expression of the interleukin-10 receptor (IL10R) on circulating leukocytes in SLE and rheumatoid arthritis, and correlate this with plasma IL-10 levels and disease activity. Methods. Peripheral blood was sampled from 20 SLE patients, 14 rheumatoid arthritis patients, and 14 healthy controls. IL-10R expression was determined by immunofluorescence labelling and flow cytometric analysis. Plasma IL-10 levels were measured by ELISA. Results. IL-10R was highly expressed on monocytes, and to a lesser degree on neutrophils in all 3 patient groups. Only a small percentage of lymphocytes expressed IL-10R in all three groups. There was no significant difference in IL-10R expression on the surface of monocytes, neutrophils or ;lymphocytes in any of the 3 groups. IL-10R expression did not correlate with plasma IL-10 levels or disease activity. Conclusion. This study has shown no difference in surface IL-10R expression between SLE, rheumatoid arthritis and normal subjects. Deficient or excessive circulating leukocyte surface IL-10R expression therefore does not seem to play a role in the pathogenesis of SLE or rheumatoid arthritis. Functional IL-10R studies would be of interest.