The relevance of antimalarial therapy with regard to thrombosis, hypercholesterolemia and cytokines in SLE.

Hydroxychloroquine has several less well-known actions that may have clinical relevance in treating systemic lupus erythematosus (SLE). (1) Hydroxychloroquine has a possible anti-thrombotic action. It is a platelet inhibitor and appears to decrease the risk of thromboembolism in patients with anticardiolipin antibodies. (2) Hydroxychloroquine is associated with lower serum cholesterol and low-density lipoprotein levels compared to those present in patients who are taking corticosteroids but not antimalarials for SLE. (3) It may also decrease abnormal levels of cytokines. Interleukin-6 (IL-6), soluble CD8 and soluble IL-2 receptors (sIL-2R) are lower in patients taking antimalarials compared to those on corticosteroids alone or on neither medication. Serum levels of CD8 and sIL-2R decrease after 6 weeks of hydroxychloroquine treatment. These findings may help explain the favorable response of SLE patients treated with antimalarials.