key: cord-0744658-g9izis24 authors: Negrea, Lavinia; Rovin, Brad H. title: Gross Hematuria Following Vaccination for SARS-CoV2 in Two Patients with IgA Nephropathy date: 2021-03-24 journal: Kidney Int DOI: 10.1016/j.kint.2021.03.002 sha: 146f8069a792229b49dff8d9b63e02d26c5e5a07 doc_id: 744658 cord_uid: g9izis24 nan To the Editor: Several of the SARS-CoV2 vaccines use a nucleoside-modified, purified mRNA lipid nanoparticle-encapsulated platform. Compared to traditional inactivated viral and adjuvanted protein vaccines, this RNA platform elicits far higher neutralizing antibody titers, stronger antigen-specific CD4 + and CD8 + T cells responses, and stronger germinal center B and T FH cell activation in experimental animals 1 . The activated CD4 + and CD8 + T cells produce several proinflammatory cytokines, including interferon-γ and tumor necrosis factor-α. This led us to wonder if these vaccines may activate or exacerbate immune-mediated glomerular diseases. Two individuals with biopsy-proven IgA nephropathy (IgAN) developed gross hematuria shortly following the second dose of the Moderna vaccine. The patients are described in the Table. At baseline, both had proteinuria below 1 gram/day and wellpreserved kidney function. Several hours after the second dose of vaccine was given, both developed systemic symptoms ranging from body aches, headache, and fatigue to fever and chills. Between 8 and 24 hours after systemic symptoms appeared, the patients noticed gross hematuria that resolved after 3 days. Serum creatinine did not increase, but proteinuria increased in one patient (Table) . Although we did not expect an exacerbation of IgAN after a non-mucosal immune challenge, IgAN patients have previously been reported to have a stronger IgA1 (albeit monomeric) response to intramuscular influenza vaccine than healthy subjects 2 . These episodes of apparent IgAN exacerbation should prompt the nephrology community to closely follow their patients with glomerular disease post SAR2-CoV2 vaccination to determine the frequency and consequences of vaccine-induced disease activation. J o u r n a l P r e -p r o o f Humoral immune response to influenza vaccination in patients with primary immunoglobulin A nephropathy. An analysis of isotype distribution and size of the influenza-specific antibodies