Impaired IL2 production by lymphocytes of patients with systemic lupus erythematosus.

The aim of this study was to define as possible abnormality of interleukin 2 (IL2) production by PHA-stimulated peripheral blood lymphocytes (PBL) in systemic lupus erythematosus (SLE). Thirty-four SLE PBL samples were stimulated to produce IL2 and compared with PBL from healthy (age- and sex-matched) controls. A significant defect in IL2 production was observed in SLE patients. This defect was not restricted to corticosteroid-treated patients and was not correlated with the presence of lymphotoxic antibodies or with clinical disease activity. Although 5-day responsiveness to phytohaemagglutinin (PHA) decreased in SLE, the SLE PHA-blasts responded as well as control blasts to semipurified IL2, suggesting that the receptor for IL2 was normally expressed on SLE blasts. In 9 cases, the effect of addition of indomethacin (2 micrograms/ml) or of an optimal amount of IL1 on PHA-induced IL2 production was studied. Indomethacin increased (22%) the IL2 yield of healthy individual PBL. In SLE, indomethacin (but not IL1) was able to completely restore (41% increase) the IL2 production of lectin-stimulated PBL (P less than 0.01). These data suggest that, in SLE, the inhibition of IL2 production is mediated by prostaglandin, possibly produced by monocytes.