Pneumocystosis in a patient with Crohn's disease treated with combination therapy with adalimumab.

Abstract Pneumocystis jirovecii pneumonia (PCP) is a potential complication of immunosuppression. Crohn's disease (CD) is an immune granulomatous disorder characterized by transmural inflammation that can affect any part of the gastrointestinal tract. Its treatment is based on steroids and immunosuppressants but in non-responders, biologic compounds such as anti-tumor necrosis factor alpha (TNF) antibodies have been used. Neutralization of TNF causes a decrease in the inflammatory response but increases susceptibility to opportunistic infections such as fungal infections. We report a young male with chronic diarrhea, fever and weight loss who was diagnosed with CD and began conventional treatment with immunosuppressants, but due to lack of response after several weeks, biologic therapy with adalimumab was initiated. Seven weeks later he developed persistent fever and upper respiratory symptoms. After chest CT, bronchoscopy and bronchial lavage, P. jirovecii was identified by silver staining and confirmed by immunofluorescence. To our knowledge this is the second case of pneumocystosis associated with the use of adalimumab in CD and the first reported Mexican case confirmed by microbiological and immunological studies in this setting.