Pneumocystis carinii pneumonia: a major complication of immunosuppressive therapy in patients with Wegener's granulomatosis.

The risk factors and clinical and laboratory parameters in Pneumocystis carinii pneumonia in patients with Wegener's granulomatosis have not been well characterized. We undertook a retrospective chart review of all patients with a diagnosis of Wegener's granulomatosis and P. carinii pneumonia who were followed at the National Institute of Allergy and Infectious Diseases of the National Institutes of Health. The chart review focused on clinical, laboratory, and roentgenologic evidence of P. carinii pneumonia. Eleven cases of P. carinii pneumonia were diagnosed in some 180 patients with Wegener's granulomatosis, for an overall incidence of approximately 6%. All patients developed P. carinii pneumonia either during the initial course of treatment or during therapy for recurrent Wegener's granulomatosis. All patients were receiving daily glucocorticoids and a second immunosuppressive therapy. Lymphocytopenia was noted in all patients, with a mean +/- SEM total lymphocyte count of 303 +/- 69 cells/microL. All patients tested (10 of 11) were seronegative for human immunodeficiency virus (HIV) infection. Eight presented with worsening chest roentgenograms compared with baseline, whereas three presented with normal chest roentgenograms. We conclude that P. carinii is a common opportunistic pathogen in patients with Wegener's granulomatosis receiving immunosuppressive therapy. Therapeutic immunosuppression (daily glucocorticoids and immunosuppressive agents) and the resultant lymphocytopenia, as well as the lymphocyte and monocyte functional abnormalities caused by glucocorticoids, may be the most likely factors predisposing to P. carinii pneumonia in patients with Wegener's granulomatosis. Based on our data, all patients with Wegener's granulomatosis should be given chemoprophylaxis against P. carinii while they are receiving daily glucocorticoids.(ABSTRACT TRUNCATED AT 250 WORDS)