A 71-year-old male with a life-threatening recurrence of hemolytic anemia, thrombocytopenia, and acute kidney injury after pembrolizumab therapy: a case report

BACKGROUND: Immune checkpoint inhibitors (ICIs) have revolutionized cancer treatment. However, their use has been restricted in patients with preexisting autoimmune diseases due to concerns about increased risk of immune-related adverse events (irAEs). CASE PRESENTATION: We present a case of a patient with stage IV lung adenocarcinoma and a history of complement-mediated autoimmune hemolytic anemia in remission. After receiving a single dose of pembrolizumab, the patient experienced life-threatening recurrent hemolytic anemia, de novo thrombocytopenia, diarrhea, myocarditis, and acute kidney injury. Laboratory tests confirmed the diagnosis of Evan's syndrome, with positive PAIgG and direct antiglobulin test. Treatment with intravenous methylprednisolone at a dose of 2 mg/kg resulted in a favorable response, with resolution of symptoms and rapid recovery of kidney function. The probable cause of pre-renal hypoperfusion (evidenced by a BUN-to-creatinine ratio of 48.1) leading to acute tubular injury was attributed to pembrolizumab-induced diarrhea. CONCLUSIONS: This case illustrates a life-threatening recurrence of complement-mediated autoimmune hemolytic anemia induced by ICIs. Clinicians should carefully consider the expected efficacy and potential toxicity before initiating ICIs therapy in patients with preexisting autoimmune diseases. Additionally, the occurrence of acute kidney injury during ICIs therapy adds complexity and requires careful differential diagnosis.