A case of rapidly progressive glomerulonephritis with double-positive anti-GBM antibody and MPO-ANCA after SARS-CoV-2 vaccination and relapse during 1 year follow-up.

Although mRNA vaccines for COVID-19 are highly beneficial and are recommended for patients with kidney disease, adverse reactions in some patients after vaccination have been problematic. Various vasculitis and renal disorders have been reported after vaccination; however, a causal relationship has not yet been identified. In this report, we describe a case of rapidly progressive glomerulonephritis that developed after SARS-CoV-2 vaccination, in which both anti-glomerular basement membrane (anti-GBM) and myeloperoxidase antineutrophil cytoplasmic antibodies (MPO-ANCA) were present. The patient's renal biopsy showed that of the 48 glomeruli in total, four showed global sclerosis and none showed segmental sclerosis. The biopsy showed 11 cellular glomerular crescents and 5 fibrocellular glomerular crescents. Renal function improved with steroids, rituximab, and plasma exchange. Approximately 9 months later, MPO-ANCA was again elevated, and the pulmonary lesions worsened, again requiring multidisciplinary treatment. This case suggests that caution should be exercised in the development of double-positive disease after vaccination, and that long-term observation may be necessary because of the possibility of relapse.

MPO-ANCA-positive Microscopic Polyangiitis Following COVID-19 Infection.

Antineutrophil cytoplasmic antibody-associated vasculitis (AAV) is a systemic disease that causes vasculitis in various organs. Although the cause of the onset is unknown, infection has been reported to be a causative factor. The subsequent cytokine storm triggered by the immune response against SARS-CoV-2 infection has been reported to lead to symptoms being more severe. We herein report our experience with the onset of AAV following COVID-19 infection. We also report the course of anti-SARS-CoV-2 serum antibody titers following induction therapy, which suggests that vaccination and education concerning standard precautions are necessary in patients who require immunosuppressive therapy, even after COVID-19 infection.

MPO-ANCA-associated vasculitis after the Pfizer/BioNTech SARS-CoV-2 vaccination.

Vaccination against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has demonstrated high efficacy at preventing coronavirus disease 2019 (COVID-19) and a favorable safety profile, however it has also been reported that COVID-19 vaccines may put increase of immune-mediated disease. We herein report a case of MPO-anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis following the mRNA vaccine BNT162b2 (Pfizer/BioNTech) for COVID-19. Although the causal relationship between vaccine and ANCA-associated vasculitis is uncertain, environmental and genetic factors may have set the stage for the development of vasculitis, and the vaccine may have triggered a domino effect.

Impaired HVJ-stimulated Interferon producing capacity in MPO-ANCA-associated vasculitis with rapidly progressive glomerulonephritis lead to susceptibility to infection.

ANCA-associated RPGN leads to renal failure through systemic vasculitis and diffuse crescentic glomerulonephritis. MPO-ANCA-RPGN patients are highly susceptible to infections. Our aim in this study was to uncover reasons why these patients were susceptible to infections. We analyzed various aspects of type I interferon system including HVJ-stimulated IFN-α producing capacity and plasmacytoid dendritic cell (pDC) number in whole blood in MPO-ANCA-RPGN patients. Compared with healthy subjects, MPO-ANCA-RPGN patients showed impaired HVJ-stimulated IFN-α producing capacity and lower pDC number with or without glucocorticoid treatment. Immuno-histological staining of MPO-ANCA-RPGN kidney samples revealed a few but apparent pDC in T cell infiltrating regions even in patients with low pDC number in their peripheral blood. Patients' low HVJ-stimulated IFN-α producing capacity and pDC numbers persisted even after patients underwent several years of treatment. Former infection was determined using patients' serum BPI, Lamp-2 and Calprotectin, since they are reflective of a history of infection. These markers were higher in MPO-ANCA-RPGN patients than in healthy subjects. These results indicate that impaired HVJ-stimulated IFN-α production as well as dysfunction of the IFN system might have resulted from a previous bout of infection and can be partially implicated in patients' long-term susceptibility and vulnerability to infection.