Phorbol myristate acetate (PMA) reverses inhibition of interleukin-2 production by T lymphocytes of patients with systemic lupus erythematosus.

Interleukin-2 (IL-2) production was studied in T lymphocytes from 23 patients with systemic lupus erythematosus (SLE) and 20 healthy volunteers. The IL-2 production by phytohemagglutinin (PHA)-stimulated cells from SLE patients was significantly depressed as compared to control values. The depressed IL-2 production by SLE T cells was largely reversed by the addition of phorbol myristate acetate (PMA), which directly activates protein kinase C. This can explain why some authors using PMA together with mitogens were not able to find a depressed IL-2 production in SLE patients. These results suggest that the defect responsible for decreased IL-2 production by SLE lymphocytes is proximal to protein kinase C activation and that probably a very early event in T cell activation is responsible for impaired IL-2 response to mitogen in patients with SLE.