CD4 and autoimmune disease: The HLA‐DRA gene is a part of the human major histocompatibility complex class II molecules, primarily involved in immune responses.S5 Research on HLA‐DRA has mainly focused on its association with various autoimmune diseases, such as RA and systemic lupus erythematosus.S6, S7 HLA‐DRA functions by presenting antigenic peptide fragments to CD4+T cells, thereby activating immune responses.S5 Our MR study revealed that down‐regulation of the HLA‐DRA gene may reduce the risk of sarcopenia.