CTLA4 and autoimmune thrombocytopenic purpura: Then among ICI monotherapy regimens, the highest number of case reports and ROR were reported for those treated with anti-PD-1 (7.4 95%CI 6.5-8.4), followed by anti-PD-L1 (6, 95%CI 4.4-8.2) and anti-CTLA-4 (4, 95%CI 2.6-6.3), which may indicate that anti-PD-1 significantly increases the risk of ITP (Ohashi et al., 2023).