A case of de novo glomerulonephritis following COVID-19 in a patient with preexistent IgA vasculitis

Abstract

During the unprecedented COVID-19 outbreak, new-onset or relapsing glomerulonephritis, such as ANCA-associated glomerulonephritis and Immunoglobulin A (IgA) nephropathy, following COVID-19 has been reported. However, to date, the association of COVID-19 with preexistent IgA vasculitis (IgAV) remains unclear. Here, we present the case of a 20-something old Japanese woman with preexistent IgAV who newly developed glomerulonephritis following COVID-19. At the diagnosis of IgAV, she had cutaneous purpura, joint pains, and gastrointestinal symptoms, but no signs of kidney involvement. Three months ago, she was tested positive for COVID-19 and subsequently developed hematuria and proteinuria. She was then admitted to our hospital and renal biopsy showed glomerular mesangial expansion and hypercellularity and cellular and fibrocellular crescents, accompanied by diffuse IgA and C3 deposits. With the diagnosis of de novo IgAV nephritis, the patient was treated with intravenous methylprednisolone followed by oral prednisolone. She had favorable responses to this treatment and has achieved and maintained the remission of hematuria and proteinuria after initiation of glucocorticoid therapy. Our case highlights that immune response to SARS-CoV-2 infection could trigger the onset of glomerulonephritis in the IgAV patients who have no renal involvement.

Keywords: COVID-19; Glomerulonephritis; Glucocorticoid therapy; IgA vasculitis.

Fig. 1

Cutaneous purpura in the lower limb

Fig. 2

Light microscope images of renal biopsy specimens. Glomerulus with mesangial expansion and hypercellularity that shows the formation of cellular and fibrocellular crescents. A Periodic acid Schiff staining. B Periodic acid-methenamine silver staining

Fig. 3

Immunofluorescent staining. Anti-Immunoglobulin A (IgA) (A) and anti-C3 staining (B) are positive in the glomerular mesangial areas

Fig. 4

Electron microscope images of glomeruli. The cell proliferation, the matrix expansion, and the electron-dense deposits are present in the glomerular mesangial area

Fig. 5

Clinical course and responses to glucocorticoid treatment. IgAV IgA vasculitis, mPSL methylprednisolone; PSL prednisolone, UPCR urine protein/creatinine [Cr] ratio, U-Bld urine blood, RBC red blood cell, HPF high power field