Delayed autoimmune hemolytic anemia in efalizumab-treated psoriasis.

Efalizumab, a humanized anti-CD11a monoclonal antibody, has been shown to treat plaque psoriasis. A known association between this drug and autoimmune thrombocytopenia has already been established. More recently publicized, however, is efalizumab's ability to affect another cell line--that of the erythrocyte--and cause an autoimmune hemolytic anemia that typically occurs 4 to 6 months after initiating therapy. In this article, we report the case of a patient who developed autoimmune hemolytic anemia after 8 months of successful treatment with efalizumab. His delayed presentation suggests that monitoring of blood cell counts longer than 6 months may be warranted.