Severe pneumonia in mycophenolate mofetil combined with low-dose corticosteroids-treated patients with immunoglobulin A nephropathy. 
The tolerance of mycophenolate mofetil (MMF; Shanghai Roche, China) in Lee Classes III, IV, and V immunoglobulin A nephropathy (IgAN) remains unclear.  This article reports nine cases of severe pneumonia (SP), including pneumocystis pneumonia (PCP) and cytomegalovirus (CMV) pneumonia, and its risk factors in MMF plus low-dose corticosteroid-treated patients with Lee Classes III, IV, and V IgAN.  Fifty-three patients with IgAN were included in this single-center study.  The treatment regimen was MMF (1-1.5 g/d) plus low-dose corticosteroids (0.5 mg/kg/d).  SP was defined as diffuse bilateral lung infiltrate with respiratory failure.  PCP was diagnosed by detecting the organisms in the sputum and bronchoalveolar lavage.  CMV infection was diagnosed through serum screening for CMV-IgG and IgM antibodies and CMV-DNA testing by a real-time polymerase chain reaction assay.  The risk factors of SP were analyzed.  Nine cases (16.9%) of SP occurred in this study.  All SP developed at approximately the 10(th)-14(th) week after the initiation of the regimen: PCP was diagnosed in four cases and CMV infection in two cases.  Renal function impairing was more serious in patients with SP than in those without SP, as evidenced by estimated glomerular filtration rate (p = 0.019) and serum creatinine level (p = 0.016).  Six of the nine SPs occurred in MMP plus low-dose methylprednisolone group, which was statistically higher than that in the MMF plus low-dose prednisone group (p = 0.000).  The incidence of SP in this study was 16.9%.  Chronically impaired renal function and the use of methylprednisolone may be the risk factors for SP.