Stereological quantification of lymphocytes in skin biopsies from atopic dermatitis patients

Atopic dermatitis (AD) is histologically characterized by lymphocytic infil tration of the skin and quantitative assessment is required. This study int roduces stereological techniques to quantify the number of lymphocytes in s kin biopsies. Four-millimetre punch biopsies were taken from skin with acti ve eczema in 8 adults with AD and from clinically normal skin from 4 of the patients. Five persons without allergy or skin disease served as controls. The mean number of lymphocytes in 4-mm skin biopsies was 469,000 and 124,0 00 in active eczema and in clinically normal skin, respectively. Compared w ith controls, the number of lymphocytes in biopsies increased by a factor o f 6.8 in; active eczema and a factor of 1.8 in clinically normal skin. If 2 0% of skin is affected by eczema the total number of lymphocytes located in the affected skin can be estimated to 1.27 x 10(10). A patient with clinic ally moderate AD has a considerable number of lymphocytes in the skin.