Immune checkpoint inhibitors induced autoimmune haemolytic anemia in patients with malignant cancer

Autoimmune hemolytic anemia (AIHA) is a rare but potentially life-threatening hematologic immune-related adverse event (irAE) associated with immune checkpoint inhibitors (ICIs). This study reports three new cases of ICI-induced AIHA from three medical centers in China and places them in the context of existing literature.

Three patients with AIHA following ICI therapy were identified from The Second Xiangya Hospital, Qilu Hospital, and Nanping First Hospital. A PubMed search up to June 1, 2026, was conducted to collect previously reported cases with sufficient clinical details.

A total of 51 cases were analyzed, including three new patients and 48 from published reports. The mean age was 65.2 years, and 47.1% were male. The most common tumor types were melanoma (49.0%) and non-small cell lung cancer (27.5%). Most cases were associated with anti-PD-1 agents, particularly pembrolizumab and nivolumab, and AIHA typically developed early during ICI therapy. Corticosteroids were the primary treatment, with 92.2% achieving hematologic recovery or improvement. Four deaths (7.8%) were attributed to severe hemolysis. All three newly identified patients had pre-existing anemia before ICI initiation.

ICI-induced AIHA usually occurs early during ICI therapy and responds favorably to corticosteroid-based treatment. Pre-existing anemia in our cases should be regarded as a hypothesis-generating observation rather than evidence of a specific risk factor, underscoring the need for early hemolysis work-up and close monitoring when anemia worsens after ICI exposure.