Hypogammaglobulinemia and bronchiectasis in mycophenolate mofetil-treated renal transplant recipients: an emerging clinical phenomenon?

Background: Mycophenolate mofetil (MMF) inhibits T- and B-cell proliferation and can cause acquired or secondary hypogammaglobulinemia. This finding and the subsequent development of opportunistic infection, including pneumonia, have been reported in patients receiving MMF. Chronic pulmonary infection and hypogammaglobulinemia predispose to bronchiectasis, and we aimed to establish the incidence and clinical pattern of this condition within our MMF-treated renal transplant population. Methods: We performed a retrospective analysis of MMF-treated transplant recipients. Two hundred and eighty-nine patients were identified and for each, demographic, clinical, radiological and laboratory data from case notes and electronic records were collected. Results: Twenty-three of 289 patients had recurrent severe chest infections (> 2 episodes) between 12 and 95 months after the introduction of MMF. The mean age was 53 +/- 17 yr. Pulmonary lesions fulfilled clinical, radiographic and computerized tomography criteria for bronchiectasis in 7/289 (2.4%). All seven patients with bronchiectasis had low serum IgG levels. Three patients had sufficient samples available for B-cell phenotype analysis but no conclusive results emerged. No cases of post-transplant bronchiectasis were identified in our transplant population not receiving MMF. Discussion: We report seven cases of bronchiectasis in renal transplant patients receiving MMF. We speculate that low immunoglobulin levels may contribute to the development of this significant pulmonary disease.