Acute Interstitial Nephritis with Glomerular Capillary IgA Deposition Following SARS-CoV-2 mRNA Vaccination

Abstract

We herein report a case of acute kidney injury (AKI) presenting as acute interstitial nephritis (AIN) after the first dose of the BNT162b2 mRNA vaccine against coronavirus disease 2019 (COVID-19). A 69-year-old man with a history of diabetes and hypertension presented with AKI 4 days after receiving the vaccine. Despite the administration of methylprednisolone pulse treatment, his renal function worsened, which prompted us to initiate temporal hemodialysis. His renal function subsequently improved, and a renal biopsy confirmed AIN and glomerular capillary IgA deposition without apparent crescents. The clinical history and histological findings suggest a relationship between severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccination and AIN as a rare side effect.

Keywords: COVID-19; SARS-CoV-2; acute interstitial nephritis; acute kidney injury; capillary IgA deposition; vaccination.

Figure 1.

Renal biopsy findings. (A) Light microscopy shows glomeruli with mild expansion of the mesangium (PAS staining, original magnification ×400). (B) Some glomeruli exhibit endocapillary hypercellularity with neutrophils in capillary tufts (PAS staining, original magnification ×400) (C-D) Interstitial inflammatory infiltration in a localized area (C: PAS staining, original magnification ×200) and tubulitis. (D: PAS staining original magnification ×400, yellow arrowheads). PAS: Periodic acid-Schiff

Figure 2.

Immunofluorescence of the glomerulus (original magnification ×200). (A) IgG was negative. (B) IgA shows linear staining along the capillary loops. (C) IgM shows mesangial granular deposits. (D) C3c presents weak staining along the capillary loops.

Figure 3.

Electron microscopy (EM) observations. EM reveals extensive foot process effacement, slight thickening of the glomerular basement membrane, and a small nodule with an increased mesangial matrix (A: original magnification ×1,500). Electron-dense deposition is shown in the subendothelial space of the glomerular tuft (B: original magnification ×3,000) and in the area of segmental sclerosis (C: original magnification ×4,000). Electron-dense deposition is also revealed in the arteriolar wall (D: original magnification ×1,500).

Figure 4.

Clinical course before and after vaccination. Changes in the serum level of Cr (mg/dL), CRP (mg/dL), UPCR (g/gCr), and urinary NAG (U/g creatinine). Cr: creatinine, CRP: C-reactive protein, UPCR: urine protein-to-creatinine ratio, NAG: N-acetyl-β-d-glucosaminide ratio