Expression of interleukin-17 in lesions of erythema multiforme may indicate a role for T helper 17 cells

INTRODUCTION: The aim of this study was to evaluate levels of interleukin (IL)-2, IL-6, IL-8, IL-10, IL-17A and interferon γ (IFN-γ) in the serum of patients with erythema multiforme (EM) and to search for the presence of IL-17-expressing cells in lesional samples of EM. MATERIAL AND METHODS: A total of 32 patients (22 females and 10 males) diagnosed with EM of the minor or major type were included in the study. Levels of IL-2, IL-6, IL-8, IL-10, IL-17A and IFN-γ in the serum were determined and compared with healthy controls. Biopsy specimens were stained with haematoxylin and eosin (HE) and monoclonal antibodies to CD4, CD8 and IL-17 for immunohistochemical examination. RESULTS: IL-2, 6, 8 and 17A were significantly higher in the patient group (p = 0.016, p = 0.001, p = 0.004, p = 0.006, respectively) and levels of IL-10 were significantly lower than in the control group (p = 0.046). The cellular infiltrate in lesions of EM was composed mainly of CD4+ T lymphocytes. The presence of IL-17-expressing cells, at proportion of 5 to 50%, was observed in the infiltrate. CONCLUSIONS: The demonstration of IL-17-expressing cells in lesions of EM in this study has brought forth the assumption that Th17 cells may be involved in the pathogenesis of EM.