An immunohistochemical study of lysozyme in the skin of psoriatic patients

The distribution of lysozyme was investigated in psoriatic skin lesions, perilesional skin and in skin from healthy controls, using the immunoperoxidase techniques avidin-biotin complex and alkaline phosphatase-anti alkaline phosphatase. Lysozyme was identified in polymorphonuclear leukocytes present in the Munro microabscesses and also occasionally in other parts of the skin, as shown by very strong cytoplasmic staining. Stratum corneum, stratum granulosum and stratum spinosum were weakly stained. In some cases positive staining along the dermal collagen bundles was demonstrated and is most likely to be related to the number of inflammatory cells in the papillary dermis. Psoriatic skin lesions stained significantly stronger for lysozyme than did perilesional skin (p < 0.0001), whereas skin from healthy controls stained weakly positive or was lysozyme negative. Lysozyme may be of some importance in the psoriatic disease process. By comparison the alkaline phosphatase-anti-alkaline phosphatase was found to be the most specific of the two techniques.