Efalizumab: a biological agent for the treatment of psoriasis.

Efalizumab is a humanized, monoclonal IgG1 antibody that binds to the alpha-subunit of lymphocyte function associated antigen (LFA)-1, blocking the interaction between LFA-1 and intercellular adhesion molecule-1. The result is a reduction in T cell activation, an inhibition of the trafficking and recruitment of T cells to the dermis and epidermis, and a decrease in the reactivation of T cells at several steps in the psoriasis pathogenesis. The clinical responses seen in efalizumab trials have demonstrated that this medication is efficacious, especially in long-term treatment. Adverse events observed in efalizumab-treated patients have been minor. Psoriasis rebound following discontinuation of treatment, while serious, has been controlled through transition to other therapies. Subcutaneous injection allows for administration outside the clinic.