As previous studies have shown that cytokines play a major role in regulating the expression of proteins that inhibit the complement system [22], we measured levels of the cytokines TNF-α (TNF) and IFN-γ (IFNG) in the sera of 38 patients with bullous pemphigoid and 19 normal controls by enzyme-linked immunosorbent assay (ELISA). Here, IFNG is linked to bullous pemphigoid.