Meephansan J, et al. – The interleukin (IL)–33 mRNA in patients’ lesional skin samples and IL–33 protein expression in patients’ serum underwent comparative analysis, prior to and after treatment with methotrexate (MTX) and narrowband ultraviolet B (NB–UVB). A correlation was observed between the IL–33 production and inflammatory skin in psoriasis, possibly via its cytokine function. The high expression of IL–33, following NB–UVB therapy, was indicative of the occurrence of unknown functions to alleviate psoriatic lesions without IL–33 involvement.