IL4 and neoplasm: Elevations in serum interleukin-4 (IL-4; an inflammatory cytokine produced by TH2 cells) levels and IL-4 receptor mRNA expression are the most distinctive manifestations of extrinsic AD [6], and treatment with calcineurin inhibitors, such as tacrolimus and pimecrolimus, relieve atopic skin symptoms by inhibiting IL-4 expression [7].