In a mouse model immunized with sheep red blood cells (SRBC) and a mouse model of chronic graft-versus-host disease (cGVHD), silencing METTL3 promoted the activation of CD4+ T cells and the differentiation of effector T cells (mainly Treg cells), increased antibody production and aggravated the lupus-like phenotype in cGVHD mice. Here, CD4 is linked to systemic lupus erythematosus.