Abstract:
Failure of desmosomal adhesion with ensuing keratinocyte separation - a phenomenon called acantholysis - can result from genetic, autoimmune or infectious proteolytic causes. Rare hereditary disorders of desmosomal formation have been identified in animals. Familial acantholysis of Angus calves and hereditary suprabasal acantholytic mechanobullous dermatosis of buffaloes appear to be similar to acantholytic epidermolysis bullosa of human beings. A genetic acantholytic dermatosis resembling human Darier disease has been rarely recognized in dogs. In autoimmune blistering dermatoses, circulating autoantibodies bind to the extracellular segments of desmosomal proteins and induce acantholysis. Autoantibodies against desmoglein-3 are found in canine pemphigus vulgaris and paraneoplastic pemphigus. Autoantibodies against desmoglein-1 have been rarely detected in dogs with pemphigus foliaceus. When circulating autoantibodies target desmogleins-1 and -3, mucocutaneous pemphigus vulgaris develops in dogs. Finally, several infectious agents can release proteases that cleave desmosomal bonds. In superficial pustular dermatophytosis of dogs and horses, Trichophyton hyphae colonize the stratum corneum, and acantholysis presumably develops because of proteases secreted by the dermatophytes. In exudative epidermitis of piglets, Staphylococcus bacteria - usually Staphylococcus hyicus- release exfoliatin toxins that bind to and specifically cleave desmoglein-1. Any of the above mechanisms can result in impairment of desmosomal function with subsequent acantholysis. The end point of adhesion failure is identical among these diseases: there is cleft formation where desmosomes are affected. The similarity of mechanisms explains why clinical and microscopic skin lesions overlap between entities, thus leaving clinicians and dermatopathologists with the conundrum of determining whether the acantholysis is of genetic, autoimmune or infectious origin.
摘要:
桥粒粘附失败与随后的角质形成细胞分离-一种称为棘皮松解的现象-可能是由遗传引起的,自身免疫或感染性蛋白水解原因。已在动物中发现了罕见的桥粒形成遗传性疾病。安格斯小牛的家族性棘皮松解和水牛的遗传性鼻上棘皮松解性机械性皮肤病似乎与人类的棘皮松解性大疱性表皮松解症相似。在狗中很少发现类似于人类Darier病的遗传性棘皮松解性皮肤病。在自身免疫性起泡性皮肤病中,循环自身抗体与桥粒蛋白的胞外段结合并诱导棘皮松解。在犬寻常型天疱疮和副肿瘤性天疱疮中发现了抗桥粒蛋白3的自身抗体。在患有天疱疮的狗中很少检测到针对desmoglein-1的自身抗体。当循环自身抗体靶向桥粒蛋白-1和-3时,在狗中发生皮肤粘膜寻常性天疱疮。最后,几种传染因子可以释放切割桥粒键的蛋白酶。在狗和马的浅表脓疱性皮肤癣菌病中,毛癣菌菌丝定植于角质层,和棘皮松解的发展可能是由于皮肤癣菌分泌的蛋白酶。在仔猪的渗出性表皮炎中,葡萄球菌-通常是金黄色葡萄球菌-释放结合并特异性切割桥粒蛋白-1的去角质素毒素。上述机制中的任何一种均可导致桥粒功能受损,并随后出现棘皮松解。在这些疾病中,粘连失败的终点是相同的:有裂隙形成,桥粒受到影响。机制的相似性解释了为什么临床和微观皮肤病变在实体之间重叠,因此,临床医生和皮肤病理学家面临着确定棘皮松解是否是遗传的难题,自身免疫或感染起源。