Everolimus-associated interstitial pneumonia in a renal transplant patient: a case report

The mTOR inhibitors (mTORi, mammalian target of rapamycin; sirolimus and everolimus) have been recently introduced in clinical practice to improve the therapeutic strategies for maintenance of organ transplant and to slow down the progression of chronic renal failure, thanks to their good immunosuppressive properties and absence of renal toxicity. Additionally, mTORi have some antineoplastic and cardioprotective effects. 
At the same time, mTORi have several collateral effects, often dose dependent and generally reversible after cessation or minimization of the drug dosage. In particular, in the last years, sirolimus-associated pulmonary toxicity has been reported. 
We describe a clinical case of a young woman with a renal transplant, followed at our Renal Transplant Center, hospitalized for fever and cough unresponsive to antibiotic therapy that, at the time of admission in our renal unit, showed a chest CT scan diagnosis compatible with a drug-related organizing pneumonia or interstitial infiltrates (BOOP).
Based on the above diagnosis, we decided to significantly reduce the mTORi dosage reaching stable trough level of 2.5-3 ug/L.
After few days, we assisted at an improvement of the clinical status, defervescence and reduction of the pulmonary symptoms. Besides, the microbiological and neoplastic laboratory tests performed on bronchial washing were negative.
At day 15, a new chest CT showed a significant reduction of multiple parenchyma areas of thickening. After 3 months, the medical conditions have improved with stable renal function. 
Our case report describes an everolimus-related “lung syndrome” successfully treated with a significant minimization of mTORi dosage. Our experience may be useful to help clinicians treating mTORi-related pulmonary complications.