A relapsing case of pulmonary-renal syndrome after a sequential rise in MPO-ANCA and anti-GBM antibodies.

A 69-year-old woman who presented with severe renal dysfunction and diffuse alveolar hemorrhage was diagnosed with pulmonary-renal syndrome (PRS) based on the coexistence of serum myeloperoxidase (MPO)-antineutrophil cytoplasmic antibodies (ANCA) and anti-glomerular basement membrane (GBM) antibodies (Ab). Hemodialysis was started; plasma exchange and intravenous methylprednisolone pulse therapy were administered followed by oral prednisolone administration. Pulmonary hemorrhage decreased; however, renal dysfunction persisted. On maintenance hemodialysis and prednisolone therapy, MPO-ANCA and anti-GBM Ab became negative at 4 and 10 months, respectively; thereafter, they became positive again at 18 and 35 months, respectively. At 36 months, there was relapse of pulmonary hemorrhage. Plasma exchange and intravenous methylprednisolone pulse therapy were administered; pulmonary hemorrhage ceased, and both antibodies became negative. It is known that PRS cases that are double positive for ANCA and anti-GBM Ab occasionally relapse after remission, and, even though they are double positive at initial diagnosis, most relapses occur with reappearance or re-elevation of ANCA but with absence of anti-GBM-Ab. Therefore, this was a rare relapsing case that presented with double-positive serology. Further, our observation that the reappearance of ANCA preceded that of anti-GBM-Ab suggests that ANCA contribute to the reproduction of anti-GBM Ab.