Chronic thrombotic microangiopathy; This is a literature report for the following literature source(s).  A 48-year-old male patient received BNT162b2 (BNT162B2), on 18Feb2021 as dose 2, single (Batch/Lot number: unknown) for covid-19 immunisation. The patient's relevant medical history included: "living unrelated transplant", start date: 2015 (not ongoing); "well controlled diabetes" (unspecified if ongoing). Concomitant medication(s) included: MYCOPHENOLATE taken for immunosuppression; SIROLIMUS taken for immunosuppression. Past drug history included: Basiliximab, notes: induction; Tacrolimus for Immunosuppressive, reaction(s): "thrombotic microangiopathy", notes: maintained on tacrolimus and mycophenolate (MMF). Vaccination history included: BNT162b2 (DOSE 1, SINGLE), administration date: 25Jan2021, for Covid-19 immunization. The following information was reported: THROMBOTIC MICROANGIOPATHY (medically significant) with onset Feb2021, outcome "unknown", described as "Chronic thrombotic microangiopathy". The patient underwent the following laboratory tests and procedures: Biopsy: (unspecified date) revealed diffuse lymphocytic interstitial, notes: inflammation, peritubular capillaritis, and C<inf>4D</inf> negative; Blood creatinine: (unspecified date) 1.9 mg/dl; (unspecified date) 2.48 mg/dl, notes: decreased, within a week; (unspecified date) 2.9 mg/dl, notes: decreased, on discharge; (2015) 10.42 mg/dl, notes: Pre-operative; (Feb2021) 3.44 mg/dl; (Feb2021) 4.27 mg/dl; DSA testing: (unspecified date) revealed Class II DSA:DQ2 (SI- 5933), Allosure, notes: 1.2 %. BK < 500 and CMV undetected; (unspecified date) No DSA Class I or II detected; (unspecified date) below 0.5, notes: unit: mg/mg. Therapeutic measures were taken as a result of thrombotic microangiopathy.  Clinical course: Complicating that effort were reported of a suboptimal response to the SARS-CoV-2 spike protein in patients on immunosuppressive medications and possible thrombotic microangiopathy (TMA) in renal transplant patients. Patient received Basiliximab induction and maintained on tacrolimus and mycophenolate (MMF). One month post-transplant patient was diagnosed with TMA. Tacrolimus was stopped and patient was switched to Sirolimus and continued on MMF. Patient was followed closely by transplant nephrology for the next 5 years with a baseline creatinine of 1.9 mg/dL, protein to creatinine ratio below 0.5 mg/mg and well controlled diabetes. No DSA Class I or II detected on regular testing. Patient was compliant with all prescribed medications. Patient received second Pfizer vaccine administered on 18Feb2021. A week later creatinine was noted to be 3.44 mg/dL. Repeat creatinine of 4.27 mg/dL. Biopsy revealed diffuse lymphocytic interstitial inflammation, peritubular capillaritis, and C4D negative. Findings consistent with chronic TMA. DSA testing revealed Class II DSA: DQ2 (SI- 5933), Allosure 1.2 %. BK < 500 and CMV undetected. Patient received therapeutic plasma exchange, IV Ig infusion and steroids while on MMF and sirolimus. His creatinine decreased to 2.9 mg/dL on discharge. Over the next 6 months graft function deteriorated. He was now CKD stage 5 and under evaluation for a second transplant. There were case reports of COVID-19 vaccine administration and transplant graft dysfunction. A possible mechanism involved the mRNA lipid nanoparticle-encapsulated platform producing such a robust CD4 and CD8 T-cell response that pro-inflammatory cytokines are activated or that immune complex associated glomerular disease occurs resulting in the development of TMA in susceptible patients.; Sender's Comments: Based on the information in the case report and a plausible temporal relationship, a possible causal association between the event and suspect drug BNT162B2 cannot be excluded. 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 regulatory authorities, Ethics Committees, and Investigators, as appropriate.