IL4 and systemic lupus erythematosus: Reduced levels of plasma OVA-specific IgG1/IgG2a; reduced levels of IL-4, IL-33, and TSLP; increased numbers of splenic Tregs; decreased numbers of eosinophils and mast cells; increased numbers of Limosilactobacillus, Faecalibacterium, and Akkermansia; activation of retinol metabolism and PPAR signaling pathway; downregulation of pathways associated with asthma, autoimmune thyroid disease, and SLE.