DISTRIBUTION OF METALLOTHIONEIN IN NORMAL AND PATHOLOGICAL HUMAN SKIN

The expression and distribution of metallothionein (MT) in frozen sect ions of normal and pathological human skin was studied using the monoc lonal antibody L2E3 directed against NIT derived from human fetal live r. Immunohistochemical staining of normal fetal and adult skin reveale d strong reactivity in basal keratinocytes of epidermis and outer hair root sheath, hair matrix cells and the secretory coil, but not the ex ocrine portion of eccrine glands; myoepithelial cells around apocrine sweat glands were similarly stained. In epidermal hyperplasia, variabl e numbers of suprabasal keratinocytes were stained, whereas in interfa ce dermatitis, interrupted stain-cell carcinomas found in the basal la yer. Weak or scattered staining was observed in squamous tumours, wher eas basal cell carcinomas did not show consistent staining. The distri bution of MT in normal skin was in line with the germinative role of b asal keratinocytes and hair matrix cells, whereas its distribution in hyperplastic epidermis was in line with experimental animal data, and reflected the increase in the germinative pool in these conditions. It is concluded that monoclonal antibody L2E3 may serve as a valuable im munohistochemical marker in diagnostic cutaneous pathology since it la bels basal keratinocytes selectively, and since it discriminates betwe en eccrine and apocrine sweat glands.