HAVCR2 and myelodysplastic syndrome: Furthermore, programmed death ligand-1 (PD-L1), T cell immunoglobulin and ITIM domain (TIGIT), T cell immunoglobulin mucin-3 (TIM-3), and CD47 expression was frequently shown to be increased in MDS [26,28,29,30,31] whereas loss of heterozygosity (LOH) of HLA class I antigens only occurred in <10% of patients [27].