PDCD1 and hepatitis A virus infection: Elevated ALT values have been observed following anti-CTLA-4 administration in 4% to 9% of patients and grade 3 or 4 hepatitis in 2% to 7% of the cases.[12,13] Incidence of liver injury among patients treated with anti-PD-1 is 4% to 7% for any grade and 1% for grade ≥ 3, whereas hepatic toxicity during combined anti-CTLA-4 and anti-PD-1 treatment is much more frequent (19%–37% for any grade and 9%–16% for grade ≥ 3).[13–15]