A biopsy-confirmed case of iga nephropathy flare-up with gross hematuria and AKI following SARS-CoV-2 vaccination successfully treated with steroid therapy

Introduction: IgA nephropathy is the most common cause of primary glomerulonephritis in people of Asian origin. It is characterized by mesangial deposition of IgA which activates Lectin and Alternative pathways that cause glomerular damage which results in hematuria and proteinuria. Untreated disease can progress to chronic kidney disease, and even end-stage kidney disease. Case Description: We describe a case of a 28-year-old male of Chinese descent who has a biopsy-proven diagnosis of IgA nephropathy (Oxford classification M1 E0 S1 T0 C1). Patient was maintained on Losartan 100 mg daily with proteinuria under 500mg per day. He presented to the nephrology clinic for an urgent visit after he experienced gross hematuria in his urine following the second dose of his COVID-19 vaccination (Moderna). His first shot of the same vaccination was 28 days ago. After receiving his second dose, patient experienced high-grade fever (Tmax of 39F) and chills. Next morning, he again experienced high-grade fevers and on the same night, he experienced gross hematuria. On his visit to the clinic, patient was feeling back to normal. His vital signs were within normal limits. Physical examination did not reveal any crackles in his lungs or lower extremity edema. Workup revealed elevated hemoglobin in his urine with 10-20 RBCs per high power field with no WBCs. Spot urine analysis revealed urine protein-creatinine ratio of 828mg/g. A 24-hour urine collection was performed which revealed urine protein excretion to be 925 mg/24hr. All these findings were consistent with a flare of his wellestablished IgA nephropathy. Since patient's urine protein excretion was less than 1g/ day, a decision was made to not start the patient on steroids and instead closely monitor the patient on his usual dose of Losartan 100 mg daily. Patient had not had any further complaints. He is to regularly follow up at our nephrology clinic. Discussion: IgA nephropathy is seen in individuals with recent mucosal infection or after administration of mucosal vaccination as these phenomena result in elevated IgA secretion that can then deposit in the mesangium. Our case is unique in the sense that a non-mucosal mRNA vaccination caused IgA flare. This could indicate a possible mucosal response to COVID-19 vaccination which can be a possible mechanism as to how the vaccine protects against COVID-19. Further investigations are necessary to examine the link between the two.