Decreased arachidonic acid release in peripheral blood monocytes of patients with systemic lupus erythematosus

Objective. To investigate the release of arachidonic acid (AA) in unfractio nated peripheral blood mononuclear cells (PBMC), separated monocytes and T lymphocytes of patients with systemic lupus erythematosus (SLE). Methods. AA release was measured in cells from 56 patients with SLE and fro m 48 controls. Of the 56 patients with SLE, 38 were receiving glucocorticos teroids and 18 were not. [H-3]AA was incorporated into the membranes of PBM C and purified subsets of monocytes and T lymphocytes. The release of [H-3] AA was measured both in nonstimulated cells cultured for 24 h and in cell c ultures stimulated by phorbol ester (PMA) and Ca2+ ionophore for 4 h. Results. In the PBMC of SLE patients not taking glucocorticosteroids, the r elease of AA was decreased in both stimulated and nonstimulated cells. Ther e was a decrease of AA production in monocytes but not in T lymphocytes, Th is phenomenon could be observed in the active and inactive phases of the di sease. Conclusion. A defect in AA production may exist in the peripheral monocytes of patients with SLE, resulting in decreased release of AA in patients not receiving glucocorticosteroid therapy.