Brief communication: sirolimus-associated pneumonitis: 24 cases in renal transplant recipients

Interstitial pneumonitis is an ill-defined side effect of sirolimus, a new immunosuppressant drug recently introduced for patients having organ transplantation.

To evaluate clinical and laboratory features of sirolimus-associated pneumonitis.

Case series.

1 transplantation center in Paris, France.

24 patients who had renal transplantation and developed sirolimus-associated pneumonitis, including 8 patients previously reported.

Symptoms; laboratory tests, including bronchoalveolar fluid analysis; and computed tomography (CT) of the chest.

Withdrawal or dose reduction of sirolimus.

Clinical symptoms included cough (23 patients), fatigue (20 patients), fever (16 patients), and dyspnea (8 patients). Computed tomography of the chest showed reticular and ground-glass opacities (4 patients), bronchiolitis obliterans-organizing pneumonia (19 patients), and lobar consolidation (1 patient). Bronchoalveolar lavage showed lymphocytic (19 patients) or eosinophilic (3 patients) alveolitis or pulmonary hemorrhage (2 patients). A reduction in the sirolimus dose resulted in transient clinical improvement in 2 patients, but discontinuation of drug therapy was eventually necessary in all patients. All patients recovered completely within 6 months.

The sirolimus trough level in patients from this single center was higher than that usually used in patients having renal transplantation.

Lymphocytic alveolitis and radiologic bronchiolitis obliterans-organizing pneumonia are the key findings in sirolimus-associated pneumonitis. Sirolimus withdrawal was associated with recovery within 6 months.