Sirolimus-induced interstitial pneumonitis in a renal transplant patient.

We report interstitial pneumonitis caused by sirolimus (Rapamune, an immunosuppressive agent) in a renal transplant patient. This rare manifestation was recently recognized as a troublesome adverse effect of sirolimus in many solid-organ transplant recipients, the majority of whom are kidney transplant recipients. While on sirolimus our patient developed cough, fever, and patchy infiltrates, which failed to respond to multiple courses of antibiotic therapy. Biopsy showed findings characteristic of drug-induced hypersensitivity pneumonitis, and excluded other entities, such as opportunistic infection. Improvement occurred only upon discontinuation of the sirolimus.