Distinct modulation by interferon-gamma (IFN-gamma) of CD23 expression on B and T lymphocytes of atopic subjects.

The low-affinity IgE receptor (FcepsilonRII/CD23) plays a role in IgE production. Cytokines participating in IgE synthesis also modulate CD23 expression on lymphocytes, but whether this modulation is different in atopic subjects remains unclear. We studied CD23 expression on B and T lymphocytes in 10 asthmatic patients with Dermatophagoides pteronyssinus hypersensitivity and 10 healthy non-atopic subjects. Studies were performed by flow cytometry, in phytohaemagglutinin (PHA) or IL-4-stimulated mononuclear cell cultures, alone or in the presence of IFN-gamma. Soluble CD23 (sCD23) released in the culture supernatants was measured by enzyme-linked immunoassay. Both PHA and IL-4 induced the expression of CD23 on lymphocytes of atopic and non-atopic subjects. Whereas PHA increased both the percentage and mean fluorescence intensity of CD23+ B and T cells, IL-4 alone did not increase the percentage of CD23+ T cells. The effects of IFN-gamma were different in both groups, since it was able to reduce the percentage of PHA-stimulated CD23+ T cells only in non-atopic individuals. In non-atopic subjects more than atopic, levels of sCD23 were increased in the supernatants of PHA and IL-4 cultures. These results show that the modulation of CD23 expression is different on B and T cells, and that IFN-gamma acts differently in atopic and non-atopic individuals.