Crescentic IgA nephropathy following SARS-CoV-2 vaccination. Report of a case

Introduction: Studies have shown that the frequency of acute kidney injury (AKI) increases in patients with COVID-19. Acute tubular necrosis has been reported to be the most common damage in these patients, probably due to impaired renal perfusion. On the other hand, different complex pathophysiological processes may be involved due to viral infection(sic)s direct effects on the renin-angiotensin-aldosterone system, the activation of coagulopathy, the cytokine storm, and the activation of the immune system. Many glomerular diseases may be seen in these patients, like anca-associated vasculitis, membranous glomerulonephritis, and IgA nephropathy. Clinical case: We present a newly diagnosed crescentic IgA nephropathy (IgAN) case after a SARS-CoV-2 infection and vaccination. A 31-year-old man with no medical history presented with gross hematuria 24 hours after SARS-CoV-2 infection. Hematuria regressed spontaneously within three days. He was vaccinated with two doses of CoronaVac (Sinovac) three months after he had been infected by SARS-CoV-2. Then he was vaccinated with the Pfizer-BioNTech COVID-19 vaccine one month after the second dose of CoronaVac (Sinovac) vaccine. He presented with gross hematuria and subnephrotic proteinuria 24 hours after the first dose of the Pfizer-BioNTech COVID-19 vaccine. A kidney biopsy was performed and showed crescentic IgA nephropathy (IgAN). He was started on methylprednisolone and angiotensin receptor blocker. Patients who receive mRNA-based vaccines demonstrate robust antibody production against the receptor-binding domain (RBD) of the S1 protein. Similar to natural infection, due to the intense stimulation of immune response from mRNA-based vaccines compared to other vaccines, the patients may produce de novo antibodies, leading to IgA-containing immune-complex deposits.Conclusions: This case highlights the immunological effects of the novel mRNA-based SARS-CoV-2 vaccines. Nephrologists should be aware of new-onset hematuria or proteinuria after SARS-CoV-2 infection or mRNA-based SARS-CoV-2 vaccine.