BACKGROUND: TAFRO syndrome is a rare disorder that causes thrombocytopenia, generalized oedema, fever, organ enlargement, and renal impairment. Few reports have suggested an association with vaccines, and few cases have undergone renal biopsy. TAFRO syndrome is often severe and fatal, and its cause is unknown. We report a case of TAFRO syndrome that occurred after vaccination with the coronavirus disease 2019 (COVID-19) vaccine.
METHODS: An 82-year-old woman received two doses of the BNT162b2 mRNA vaccine 3 weeks apart. Two weeks later, she was admitted to the hospital with oedema, accompanied with renal failure and thrombocytopenia. After close examination, she was diagnosed with TAFRO syndrome. She was treated with steroids, cyclosporine, and thrombopoietin receptor agonists. The patient was discharged after several months in remission.
CONCLUSIONS: Although an incident of TAFRO syndrome after COVID-19 vaccination has been previously reported, this is a rare case in which the patient went into remission and was discharged. A renal biopsy was also performed in this case, which was consistent with previous reports. The favorable treatment course for TAFRO syndrome provides valuable insights.

Management of refractory immune thrombocytopenia frequently involves rituximab, a chimeric anti-CD20 monoclonal antibody, to target B cells and induce remission in most patients. However, neutralizing antibodies to rituximab that nullify therapeutic response and may lead to serum sickness have been rarely reported. Here, we present a case of a young adult woman with Evans syndrome treated with rituximab, complicated by the development of serum sickness, acute respiratory distress syndrome, and platelet refractoriness presumed secondary to neutralizing antibodies to rituximab. She was successfully treated with the humanized anti-CD20 monoclonal antibody, obinutuzumab, with subsequent symptom resolution. Additionally, a review of 10 previously published cases of serum-sickness associated with the use of rituximab for idiopathic thrombocytopenic purpura (ITP) is summarized. This case highlights that recognition of more subtle or rare symptoms of rituximab-induced serum sickness is important to facilitate rapid intervention.