CTLA4 and type 1 diabetes mellitus: Although HLA typing of our patient was not evaluated, the frequency of HLA-DR4 was reported to be proximally 40% to 60% in ICI-induced-T1DM and was much higher than that in conventional T1DM.[3] Beyond HLA-risk genotype, single-nucleotide polymorphisms in PD-1/PD-L1 and CTLA-4 are potential biomarkers to predict T1DM susceptibility.[9]