IL10 and systemic lupus erythematosus: While UVB radiation can up-regulate Th2 cells and down-regulate Th1 cells, induce IL-10 production, increase type I IFN expression, and prolong T cell activation to increase SLE risk (29–31), another subset of UV radiation, UVA, is used as a phototherapy modality to treat cutaneous forms of lupus (112).