Two cases of acute leukopenia induced by colchicine with concurrent immunosuppressants use in Behçet's disease.

Colchicine-induced leukopenia usually occurrs in intentional or accidental overdoses or inappropriate use in combination with intravenous and oral colchine; however, there have been several reports of hematologic toxicity in short-term and small-dose colchicine medication courses. We present two cases of leukopenia induced by colchicine use concurrent with immunosuppressants in Behçet's disease. We postulate that the mechanism of colchicine-induced leukopenia might be the destruction of circulating leukocytes and an inhibition of leukocyte production by the immediate and direct toxic effect of colchicine on idiosyncrasies unique to each patient. The concurrently administered immunosuppressant might decrease the threshold for hematologic toxicity of colchicine in the leukocytes and their precursor cells.