The biological and clinical activity of anti-malarial drugs in autoimmune disorders.

Chloroquine and hydroxychloroquine are 4-aminoquinoline compounds commonly employed as anti-malarial drugs. Chloroquine and its synthetic analogue, hydroxychloroquine also belong to the disease-modifying anti-rheumatic drug class because these drugs are immunosuppressive. The immunosuppressive activity of chloroquine and hydroxychloroquine is likely to account for their capacity to reduce T-cell and B-cell hyperactivity as well as pro-inflammatory cytokine gene expression. This review evaluated experimental and clinical trials results as well as clinical response data relative to the use of chloroquine and/or hydroxychloroquine as first-line medical therapies in systemic lupus erythematosus, rheumatoid arthritis, primary Sjogren's syndrome, the anti-phospholipid syndrome and in the treatment of sarcoidosis. A primary outcomes measure in these clinical trials was the extent to which chloroquine and/or hydroxychloroquine reduced disease progression or exacerbations and/or the use and dosage of corticosteroids. The relative efficacy of chloroquine and hydroxychloroquine in modifying the clinical course of these autoimmune disorders is balanced against evidence that these drugs induce adverse effects which may reduce their use and effectiveness in the therapy of autoimmune disorders.