Interleukin 1 alpha (IL-1 alpha) in human skin in vivo: lack of correlation to markers of collagen metabolism.

Levels of interleukin 1 alpha (IL-1 alpha) were studied from blister fluids collected from 14 patients with various types of blistering diseases. In all the fluids, IL-1 alpha could be detected, the concentrations varying from 5 to 1730 pg/ml. For comparison IL-1 alpha was also assayed from suction blisters of 13 subjects; 8 atopic patients and 5 healthy controls. IL-1 alpha was also present in suction blisters in measurable quantities, suggesting that during suction IL-1 alpha is released into the blister cavity. Since IL-1 alpha has been shown to have marked effects on collagen metabolism, the marker of collagen synthesis (carboxyterminal propeptide of type I procollagen (PICP)) and gelatinase were assayed from the same samples. There was no apparent correlation between the levels of IL-1 alpha, PICP or gelatinase in blister fluids. The possible association of IL-1 alpha and collagen metabolism was further studied in experimental conditions. Topical glucocorticoid markedly decreased the level of PICP in suction blisters but did not have any significant effect on IL-1 alpha. UVB-radiation, on the other hand, caused increase in IL-1 alpha but did not have any profound effect on collagen metabolism. During the re-epithelialization of the blister floor the level of IL-1 alpha decreased markedly, and at the same time the expression of gelatinase was increased. The results indicate that IL-1 alpha is released in large quantities into blister fluid when using the suction blister model. However, no apparent correlation could be observed in healthy or diseased skin between the levels of IL-1 alpha, collagen synthesis marker or gelatinase.