Analysis of epidermal blister fluid has shown that more than 80% of the T cells in EM skin lesions express C‐C chemokine receptor type 5 and C‐X chemokine receptor 3 as well as IFN‐γ, suggesting a type 1 CD4+ T helper (Th1) cell response [24, 25, 26]. This evidence concerns the gene IFNG and erythema multiforme.