New Onset Anti-GBM Glomerulonephritis on a Background of IgA Nephropathy Post-SARS-CoV-2 Vaccination; New Onset Anti-GBM Glomerulonephritis on a Background of IgA Nephropathy Post-SARS-CoV-2 Vaccination; This is a literature report for the following literature source:   A 41-year-old female patient received BNT162b2 (BNT162B2), in Jun2021 as dose 1, single (Batch/Lot number: unknown) and in Jul2021 as dose 2, single (Batch/Lot number: unknown) for covid-19 immunisation. The patient's relevant medical history included: "hypothyroidism" (unspecified if ongoing); "COVID-19", start date: Apr2021 (unspecified if ongoing), notes: was tested positive for Covid-19 in April 2021. The patient's concomitant medications were not reported. The following information was reported: ANTI-GLOMERULAR BASEMENT MEMBRANE DISEASE (hospitalization, medically significant, life threatening), IGA NEPHROPATHY (hospitalization, medically significant, life threatening), outcome "recovering" and all described as "New Onset Anti-GBM Glomerulonephritis on a Background of IgA Nephropathy Post-SARS-CoV-2 Vaccination". The patient underwent the following laboratory tests and procedures: Anti-glomerular basement membrane antibody (normal high range <1): (2021) 4.6, notes: elevated; Biopsy kidney: (2021) performed to confirm the diagnosis, which showed, notes: acute anti-GBM nephritis - crescentic glomerulonephritis with 2-3+ linear IgG staining with incidental mesangial IgA deposits; Blood bicarbonate: (2021) 16 mmol/L, notes: metabolic acidosis; Blood creatinine: (2021) 9.8 mg/dl; Blood immunoglobulin A: (2021) elevated; Blood immunoglobulin G: (2021) elevated; Blood potassium: (2021) 5.4; Blood test: (Apr2021) Anaemia; Blood urea: (2021) 70 mg/dl; Blood urea nitrogen/creatinine ratio: (2021) 81/10.13 mg/dl; Chest scan: (2021) negative; Haemoglobin: (2021) 6.8 g/dl; Immunology test: (2021) negative; Complete review of systems: (2021) unremarkable, notes: with no signs of extrarenal manifestations; Protein urine: (2021) 5.7 g/dl; Protein urine: (2021) 300 mg/dl; Red blood cells urine: (2021) greater than 50 per high power field (HPF); Renal function test: (2021) gradually improved, notes: on treatment regimen; SARS-CoV-2 antibody test: (Apr2021) Positive; Urine analysis: (2021) revealed significant microscopic hematuria and, notes: proteinuria. Therapeutic measures were taken as a result of anti-glomerular basement membrane disease, iga nephropathy.  Additional information: Introduction: Anti-glomerular basement membrane (anti-GBM) nephritis is a rare, but potentially fatal pathology that occurs due to development of IgG autoantibodies against an autoantigen expressed in the basement membrane of kidneys. The authors present a case of anti-GBM nephritis as an uncommon immune-mediated adverse effect post mRNA Covid-19 vaccination. Case Description: This is a 41-year-old female with a history of hypothyroidism, who was tested positive for Covid-19 in April 2021. Post-covid, she received the Pfizer-SARS-CoV vaccine in June and July 2021. Few weeks later, she presented with anemia to her primary care physician, and a couple of months after, a urinalysis revealed significant microscopic hematuria and proteinuria. Further workup revealed a blood urea nitrogen (BUN) of 70 mg/dL and serum creatinine of 9.8 mg/dL which subsequently led to hospitalization for workup of acute kidney injury. Her labs were significant for hemoglobin 6.8 g/dL, BUN/Creatinine 81/10.13 mg/dL, potassium of 5.4, metabolic acidosis (HCO3 16mmol/L), and a urinalysis showing >50 red blood cells (RBCs) per high power field (HPF) with a protein of 300 mg/dL and 24-hour protein excretion of 5.7 g/dL. Complete review of systems was unremarkable with no signs of extrarenal manifestations and negative chest imaging. Immunological workup was negative except for elevated anti-GBM titer at 4.6 (normal <1) and elevated IgG and IgA serum proteins. A renal biopsy was performed to confirm the diagnosis, which showed acute anti-GBM nephritis - crescentic glomerulonephritis with 2-3+ linear IgG staining with incidental mesangial IgA deposits. She was initiated on IV pulse steroids, plasma exchange therapy, and IV Cyclophosphamide. Renal function gradually improved on this treatment regimen. Discussion: The occurrence of anti-GBM nephritis with concomitant IgA nephropathy post-SARS-CoV-2 mRNA vaccination has been rarely reported in literature. The etiology remains speculative; however, these cases highlight the need to exercise vigilance in patients presenting with symptoms or lab findings suggesting acute kidney injury with a preceding history of recent vaccination. Early identification and intervention may prevent progression of disease.; Sender's Comments: Based on the current available limited information in the case provided, the causal association between the events Anti-glomerular basement membrane disease, IgA nephropathy and the use of suspect product BNT162b2 cannot be fully excluded. The case will be reassessed once further information is available The impact of this report on the benefit/risk profile of the Pfizer product is evaluated as part of Pfizer procedures for safety evaluation, including the review and analysis of aggregate data for adverse events. Any safety concern identified as part of this review, as well as any appropriate action in response, will be promptly notified to RAs, Ethics Committees, and Investigators, as appropriate.