Response of normal human keratinocytes to sulfur mustard: cytokine release

Cytokines play a major role in both acute and chronic inflammatory processes, including those produced by sulfur mustard (2,2'-dichlorodiethyl sulfide, HD). This study describes responses of normal human epidermal keratinocytes (NHEK) to HD, defined by interleukin-1beta (IL-1beta), IL-6, IL-8 and tumor necrosis factor alpha (TNF-alpha) release. Commercially available enzyme-linked immunosorbent assay (ELISA) kits were used to measure the cytokine release in NHEK during exposure to 100 and 300 microM of HD. Exposure to 100 microM HD increased the release of cytokines. The amounts of IL-8 and TNF-alpha present in cell suspensions increased up to 59-fold and 4-fold, respectively, above control levels when NHEK were exposed to 300 microM HD. Exposure of NHEK to 300 microM HD had a highly variable effect on the release of IL-1beta, where sometimes the secretion of IL-1beta increased above baseline level and at other times it decreased in cell suspensions. Supernatants were collected from cell culture flasks 24 h after exposure of 100 and 300 microM HD and significantly increased levels of IL-6 were observed. Interleukin-6 was released in a concentration-dependent manner, 3.6-fold up to 8.4-fold, respectively, in supernatant. These pro-inflammatory mediators IL-1beta, IL-8, TNF-alpha and IL-6 may play an important role in HD injury. The present findings suggest that the cytokine changes detected could be used as potential biomarkers of cutaneous vesicant injury.