CD4 and autoimmune disease: An earlier proinflammatory environment with cytokine release by TCR‐independent bystander activation facilitates the upregulation of MHC‐II antigens to optimize antigen presentation, thereby enhancing CD4+ T cell activation, while also allowing low‐affinity, rare self‐antigen pMHC complexes to interact with autoreactive TCRs.[14] CD4+ T cells, particularly the Th1 and Th17 subpopulations,[15] play an important part in driving the pathogenesis of autoimmune diseases and inflammatory responses by secreting cytokines like IL‐17 and IFN‐γ.