HLA-B and Absence of circulating granulocytes: Recent genetic studies have identified the close genetic susceptibility of ATD‐induced agranulocytosis, namely, thionamide‐induced agranulocytosis (TIA), in various ethnic groups, especially those genes that encode the major HLAs with alleles HLA‐B*38:02, HLA‐B*27:05, and HLA‐DRB1*08:03.4, 5, 6, 7, 8