Glomerulonephritis and Interstitial Nephritis Originating from Vasculitis of the Interlobular Arteries of the Kidney in a Patient with Eosinophilic Granulomatosis with Polyangiitis

Abstract

Eosinophilic granulomatosis with polyangiitis (EGPA) is a type of antineutrophil cytoplasmic antibody-associated vasculitis. Patients often present with peripheral neuropathy and purpura, suggesting impairment of small vessels, especially capillaries. However, medium-sized vessels and small vessels with a vascular diameter larger than that of capillaries may also be impaired, causing atypical findings. We report a case of EGPA treated with corticosteroids, cyclophosphamide, and mepolizumab. Renal biopsy revealed vasculitis of the interlobular arteries as the cause of glomerulonephritis and interstitial nephritis. This case suggests the importance of considering vessels upstream of capillaries dominant EGPA as a differential diagnosis in patients with eosinophilia.

Renal involvement in eosinophilic granulomatosis with polyangiitis

“…The MIRRA RCT, which investigated the efficacy and safety of mepolizumab compared to placebo in achieving remission in EGPA patients without organ-or life-threatening manifestations, demonstrated a higher percentage of remission and more weeks in remission in patients treated with mepolizumab, allowing a reduction in the GCs cumulative dose (16). Some case reports described the effectiveness of mepolizumab as an add-on therapy to induce remission, in particular in the case of pure interstitial nephritis (57)(58)(59). Mepolizumab was given in addition to GCs and CYC (59), or to GCs alone (57,58).…”

“…Some case reports described the effectiveness of mepolizumab as an add-on therapy to induce remission, in particular in the case of pure interstitial nephritis (57)(58)(59). Mepolizumab was given in addition to GCs and CYC (59), or to GCs alone (57,58). In another case report, the addition of mepolizumab to GCs and RTX achieved successful treatment of a case of EGPA with multiorgan involvement, notably including renal damage determined by necrotizing pauci-immune glomerulonephritis and severe interstitial nephritis (60).…”