Post-COVID-19 Vaccine Activation of IgA Vasculitis

Background: A 69 year old female with hypertension and longstanding microscopic hematuria received Pfizer BioTech SARS-COV-2 vaccine. Three weeks post vaccination, the patient developed diffuse abdominal pain and a palpable, right lower extremity purpuric rash. Methods: Skin biopsy was consistent with leukocytoclastic vasculitis. Serologic workup was negative. Kidney function was normal, but there was newly identified proteinuria on urinalysis and redemonstrated microscopic hematuria. Urine protein/creatinine ratio was 1.6 g/g. Histopathologic examination revealed mild mesangial hypercellularity and immunofluorescense showed IgA dominant mesangial staining (Fig 1). Electron microscopy showed mesangial deposits. The constellation of symptoms and biopsy findings were consistent with an IgA Vasculitis, suspected to be associated with recent SARS-CoV-2 vaccination. The patient was treated with ace inhibition and sglt2 inhibition, resulting in reduction in proteinuria to less than 200 mg/g and preservation of renal function. The rash resolved with no additional intervention. Results: Development of abdominal pain, purpuric rash and sub-nephrotic proteinuria after vaccination raises possibility that SARS-CoV-2 vaccination may have triggered a de-novo IgA vasculitis or, given the longstanding, unexplained microscopic hematuria, may have exacerbated a pre-existing, otherwise quiescent IgA nephropathy. Conclusion: In susceptible individuals, an aberrant immune response triggered by vaccination may result in production and deposition of galactose deficient-IgA1 in glomeruli, activating an inflammatory cascade leading to glomerular injury and possibly a systemic vasculitis. However, despite the temporal association, both a causative link between, and pathogenic mechanisms underlying SARS-CoV-2 vaccination and IgA vasculitis remain incompletely elucidated.Figure 1