A small population of resident T-lymphocytes is present in the healthy epidermis of skin from humans, mice, cattle, and sheep. Resident lymphocytes were not found in the epidermis or adnexal epithelia of healthy skin from cats and horses. Skin-biopsy specimens from the normal skin of the dorsolateral thorax from 29 dogs were examined histologically and immunohistochemically for the presence of lymphocytes, CD3+ (T-lymphocytes), and Pax5+ (B-lymphocytes) cells in the epidermis and adnexal epithelia. All examinations were negative. It appears that lymphocytes rarely occur, or occur in very small numbers, in the epidermis and adnexal epithelia of normal dog skin.
View full abstract