Granulomatous Pneumocystis jiroveci pneumonia in a patient with chronic lymphocvtic leukemia:: A literature review and hypothesis on pathogenesis

Background: Pneumocystis jiroveci pneumonia occurs frequently in patients with immunodeficiency syndromes, especially AIDS. Approximately 5% of AIDS patients have atypical granulomatous histology. Case Report/Methods: A 75-year-old woman with chronic lymphocytic leukemia was treated with alemtuzumab (campath-1H) 3 times weekly for 12 weeks. After completion of therapy she presented with dyspnea, hypoxemia, and bilateral infiltrates. Bronchoscopy with biopsy revealed Pneumocystis organisms with granulomatous history. She responded well to trimethoprim-sulfamethoxazole. Results/Literature Review: Our literature review identified 19 patients without AIDS who had granulomatous Pneumocystis infection. These patients often had nodular infiltrates on x-rays and negative bronchoalveolar lavage study findings. Most patients required open lung biopsies. Histologic specimens frequently revealed necrosis. These patients responded well to therapy. Conclusion: The limited information available from these studies suggests that these patients have immune reconstitution-like syndrome related to either increasing numbers of CD4+ lymphocytes following therapeutic suppression or impaired modulation of CD4+ function. This unusual clinical presentation may delay diagnosis and effective therapy.