Ten patients with moderate to severe atopic dermatitis had increased levels of IgE in the blood and a reduced level of T cells with Fc receptors for IgG (T gamma). After pronase and trypsin digestion of Fc receptors, cultured T cells regenerated the Fc receptors, but preserved the difference between patients and controls. Neuraminidase treatment increased the T gamma-cell level in both patients and controls. Serum from patients with atopic dermatitis could not reduce the T gamma-cell expression in the controls. With regard to Fc receptors, no qualitative difference was observed between patients and controls, but a genuine quantitative difference accounts for the observed reduction of T gamma cells in blood.