Blood eosinophilia in tacrolimus-treated patients - An indicator of Pneumocystis carinii pneumonia

Background Pneumocystis carinii pneumonia (PcP) in immunocompromised patien ts is suggested if the following symptoms develop: dyspnea, fever, and inte rstitial infiltrates on chest x-ray. We observed a significant blood eosino phillia in kidney recipients with PcP under immunosuppressive treatment wit h tacrolimus. Methods. Blood eosinophil counts of kidney recipients under immunosuppressi on with tacrolimus suffering from PcP were compared to eosinophil counts of patients without evidence of PcP and Co patients showing PcP under immunos uppression with cyclosporine. Results. PcP-positive patients treat-ed with tacrolimus showed a significan tly higher blood eosinophil count compared to PcP-positive patients treated with cyclosporine (P=0.01), and to patients under immunosuppression with t acrolimus without PcP, respectively (P=0.006). Eosinophilia preceded the ti me of a definitive PcP diagnosis by bronchoalveolar lavage and decreased af ter successful treatment. Conclusions. An increasing blood eosinophil count can be an indicator of P. carinii pneumonia in patients under immunosuppressive therapy with tacroli mus.