Blister fluid cytokines in cutaneous inflammatory bullous disorders

Cytokines are important regulators of immune and inflammatory reactions in the skin, and may contribute to inflammatory blister induction. We examined the profiles of interleukin-6 (IL-6) and tumour necrosis factor-alpha (TNF-alpha) in fluid of spontaneous blisters in the immune-based inflammatory disorders bullous pemphigoid (8 patients), allergic contact dermatitis (5 patients) and toxic epidermal necrolysis (5 patients). These were compared with levels in 9 patients with burns, i.e. inflammatory blisters of non-immune aetiology, and 4 patients with blisters of physical origin. Very high levels of IL-6 were found in bullous pemphigoid and toxic epidermal necrolysis (p<0.001) compared with non-inflammatory and burn blisters. TNF-alpha levels were high in bullous pemphigoid and burns, but undetectable in non-inflammatory blisters. The pattern in bullous pemphigoid (very high IL-6, high TNF-alpha) differed substantially from toxic epidermal necrolysis (very high IL-6, low TNF-alpha), while burns and allergic contact dermatitis showed lesser elevation of both cytokines. Hence, differences in cytokine profiles were identified, although the relevance to underlying pathomechanisms is uncertain.