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

Abstract

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.

Clinical features and prognosis of MPO-ANCA and anti-GBM double-seropositive patients

“…The scientific community had put forward many hypotheses about the two antibodies, although the mechanism of action between them has not been clearly studied. Several studies suggested that AAV might develop first following its natural disease history, and then anti-GBM antibodies could emerge with corresponding clinical manifestation (15)(16)(17)(18). It warrants further study to explore the differences between isolated MPO-ANCA or anti-GBM positive and double positive types, including original serological, immunological, pathological and prognostic index.…”