CD4 + T cell responses restricted by HLA-DR alleles are stronger than those restricted by HLA-DQ and HLA-DP alleles and thus possess stronger immune response capabilities.[44] Previous views believed that decreased T cell activation was associated with decreased subclinical atherosclerosis.[45] This implies that HLA-DR CD4 + T cells with stronger immune activity can promote atherosclerosis, thereby inducing and promoting HF. The gene discussed is CD4; the disease is hydrops fetalis.