Aims: Exposure to mustard gas leads to acute and chronic toxic effects on the skin. Results from several studies have been suggested the role of immune mediators, including Interleukin-18, in the pathogenesis of diseases associated with the urticaria appearance. The aim of present study was to investigate the association between Interleukin-18 and its binding protein and chronic urticaria in veterans.

Materials & Methods: In this historical cohort study, 372 Sardasht veterans exposed to mustard gas and 128 healthy people (residents of the Rabat City, Iran) were studied. The both "exposed" and "control" groups were homogeneous in terms of gender, age, body mass index, and marital status. All subjects were studied and divided by an experienced skin specialist for skin disorders such as urticaria. Interleukin-18 serum levels and its binding protein were measured by sandwich ELISA methods. Mann-Whitney test was performed to compare cytokines serum levels of in the studied groups.

Findings: 8 (2.1%) of exposed group and 1 (0.8%) of control group had chronic urticaria. There was no significant difference in Interleukin-18 level mean in exposed group with urticaria compared to control group mean without urticaria (p=0.17). The difference of Interleukin-18 level between the samples with and without urticaria of the exposed group was significant (p=0.025) and higher in the persons with urticaria. No significant difference was observed in Il-18bp level mean in exposed group with urticaria compared to control group without urticaria (p=0.784).

Conclusion: IL-18 may be involved in the occurrence of urticaria induced by mustard gas.