The cellular infiltrate and its measurement in contact dermatitis.

It is well known that in the fully developed allergic contac reaction a marked cellular infiltrate takes place in the upper corium and epidermis. In the first part of this paper a short survey is given about the different cells taking part in the infiltrate and the efforts to differentiate both mononuclear and polymorphonuclear cells. In the second part is an account of our quantitative cell studies in experimental contact allergy in guinea pigs. Variations in the increase of mononuclear cell infiltration in epidermis or in the upper dermis seem to reflect the degree of hypersensitivity. Similarly a highly significant polymorphonuclear cell increase is seen in the allergic contact reaction compared to normal control skin, and basophils seem to predominate. The influence of cyclophosphamide methotrexate and corticosteroids on the cellular infiltrate of allergic contact reactions during its development has been studied.