Pneumocystis jiroveci pneumonia in patients with systemic lupus erythematosus after rituximab therapy.

Pneumocystis jiroveci pneumonia (PCP) is an uncommon but potentially life-threatening infection in immunocompromised patients with low blood T cells. Rituximab, a chimeric human/murine monoclonal antibody against the B cell-specific antigen CD20, has been increasingly used and appears to be effective in the treatment of autoimmune disorders, including systemic lupus erythematosus (SLE). PCP has been reported in some patients with autoimmune diseases or lymphoma subjected to rituximab treatment, but has not yet been reported in SLE patients. We report PCP in two patients with SLE after rituximab treatment. Fever and respiratory symptoms associated with diffuse pulmonary infiltrates developed within weeks after rituximab therapy. One patient died of respiratory failure. Another patient recovered uneventfully after treatment with clindamycin and primaquine.