Expression of eotaxin, interleukin 13 and tumour necrosis factor-alpha in dermatitis herpetiformis

BACKGROUND: The dermal and perivascular infiltrate in dermatitis herpetiformis (DH), which is mainly composed of CD4+ lymphocytes, neutrophils and eosinophils, is believed to play an important part in the pathogenesis of the disease. Previous studies suggest that cytokines such as interleukin (IL) -8, granulocyte-macrophage colony-stimulating factor, IL-4 and IL-5 could be involved in the pathogenesis of DH. These cytokines appear to drive tissue infiltration and maturation of eosinophils. Part of the effect of T-helper (Th) 2-type cytokines (IL-4, IL-5) on eosinophils could be mediated by eotaxin, which is a highly specific chemotactic protein induced by various cytokines [IL-4, IL-13, tumour necrosis factor (TNF) -alpha and interferon-gamma]. OBJECTIVES: To evaluate the expression of eotaxin and its inducers, IL-13 and TNF-alpha, in DH. METHODS We examined lesions collected from 10 DH patients with active disease. Sections from each specimen were incubated with anti-IL-13, anti-TNF-alpha and anti-eotaxin antibodies. Chloroacetyl esterase reaction was performed to show mast cell infiltration. RESULTS: Eotaxin was mainly expressed at the tips of the dermal papillae, within the microabscesses. Positivity was also found in the lymphomonocytic infiltrate in the dermis. IL-13 was expressed in the dermal infiltrate and TNF-alpha was found in the inflammatory infiltrate and in dermal vascular cells. CONCLUSIONS: These findings confirm the importance of the lymphomonocytic infiltrate and of Th2 cytokines in the pathogenesis of this disease, suggesting that tissue infiltration in DH is mediated by cell-specific chemokines such as eotaxin and not only by non-specific chemokines such as IL-8.