Takematsu H, Tagami H
Department of Dermatology, Tohoku University School of Medicine, Sendai, Japan.
Arch Dermatol. 1993 Jan;129(1):74-80.
Psoriatic scale extracts contain a unique chemotactic peptide fraction that is likely to be involved in the induction of rhythmic transepidermal leukocyte chemotaxis. Recent studies have identified the presence of two unrelated chemotactic peptides in this fraction, ie, C5a/C5a des Arg and interleukin 8 (IL-8), and its related cytokines. To investigate their relative contribution to the transepidermal leukocyte migration as well as their interrelationship in psoriatic lesions, we have quantified concentrations of immunoreactive C5a/C5a des Arg and IL-8 in psoriatic lesional scale extracts and those from related sterile pustular dermatoses such as subcorneal pustular dermatosis and pustulosis palmaris et plantaris.
The concentrations of C5a/C5a des Arg and IL-8 were more significantly increased in the horny-tissue extracts from lesional skin than in those from noninflammatory orthokeratotic skin (P < .01). The increase of C5a/C5a des Arg concentration was specific to the lesional scale extracts, but showed a rather wide range of variation. By contrast, IL-8 concentration, although consistently increased in the lesional scale extracts, was also moderately increased even in noninflammatory scale extracts prepared from ichthyosis vulgaris. The elevation of IL-8 levels in psoriatic lesions was also confirmed by measuring their levels in cutaneous tissue fluid samples collected from suction blisters. However, unexpectedly, some control samples obtained from normal skin also showed a moderate increase in the IL-8 level. Neutrophil chemotactic activity correlated significantly only with the levels of C5a/C5a des Arg in the scales (P < .05). No such significant correlation was found between chemotactic activity and IL-8 or between C5a/C5a des Arg and IL-8.
Based on these results, we speculate that, although IL-8 may exert a synergistic effect with C5a/C5a des Arg in the induction of transepidermal leukocyte chemotaxis, it constitutes a proinflammatory cytokine that is involved in the production of the persistent inflammatory changes characterized by a T-lymphocyte infiltration. In contrast, C5a/C5a des Arg seems to be generated only in the inflammatory lesional skin under specific circumstances that preferentially favor complement activation and also seems to play a major role in the induction of cyclic transepidermal leukocyte chemotaxis from "squirting papillae."
银屑病鳞屑提取物含有一种独特的趋化肽组分，可能参与节律性经表皮白细胞趋化作用的诱导。最近的研究已确定该组分中存在两种不相关的趋化肽，即C5a/C5a去精氨酸和白细胞介素8（IL-8）及其相关细胞因子。为了研究它们对经表皮白细胞迁移的相对贡献以及它们在银屑病皮损中的相互关系，我们对银屑病皮损鳞屑提取物以及相关无菌脓疱性皮肤病（如角层下脓疱性皮肤病和掌跖脓疱病）的鳞屑提取物中免疫反应性C5a/C5a去精氨酸和IL-8的浓度进行了定量。
皮损皮肤角质组织提取物中C5a/C5a去精氨酸和IL-8的浓度比非炎性正角化皮肤提取物中的浓度显著升高（P <.01）。C5a/C5a去精氨酸浓度的升高在皮损鳞屑提取物中具有特异性，但变化范围相当大。相比之下，IL-8浓度虽然在皮损鳞屑提取物中持续升高，但在寻常型鱼鳞病制备的非炎性鳞屑提取物中也有适度升高。通过测量从抽吸水疱收集的皮肤组织液样本中的水平，也证实了银屑病皮损中IL-8水平的升高。然而，出乎意料的是，从正常皮肤获得的一些对照样本中IL-8水平也有适度升高。中性粒细胞趋化活性仅与鳞屑中C5a/C5a去精氨酸的水平显著相关（P <.05）。在趋化活性与IL-8之间或C5a/C5a去精氨酸与IL-8之间未发现这种显著相关性。
基于这些结果，我们推测，虽然IL-8在诱导经表皮白细胞趋化作用中可能与C5a/C5a去精氨酸发挥协同作用，但它是一种促炎细胞因子，参与以T淋巴细胞浸润为特征的持续性炎症变化的产生。相比之下，C5a/C5a去精氨酸似乎仅在特定情况下在炎性皮损皮肤中产生，这些情况优先有利于补体激活，并且似乎在从“喷射乳头”诱导周期性经表皮白细胞趋化作用中起主要作用。
