Immunoregulation in atopic dermatitis: functional analysis of T-B cell interactions and the enumeration of Fc receptor-bearing T cells.

Immune aberrations in atopic dermatitis (AD) are multiple and interrelated. We investigated immunoregulatory cell markers and functional interactions of purified T- and B-enriched cells in a pokeweed mitogen (PWM)-stimulated IgG production assay in patients with AD. Atopic mononuclear leukocytes and autologous recombinations of purified atopic T and B cells were hyporesponsive to PWM stimulation of IgG synthesis. When atopic B cells were cultured with normal T cells, they were still less responsive than normal B cells. Atopic T cells generated normal levels of suppression in three responder systems. Radioresistant T-cell help was also in the normal range whereas nonirradiated AD T cells produced slightly less help than normal T cells. We noted reduced levels of T lymphocytes with FcIgG receptors (T gamma) and found that T gamma reduction correlated inversely with log serum IgE. In the light of normal T suppression, we critically examined AD cell adherence and contamination at various steps in the T gamma assay to rule out technical causes of T gamma reduction in AD. Lowered T gamma cells in AD were not associated with circulating IgG immune complexes and subsequent blockade of the FcIgG receptors. Thus, we have identified defects in the numbers of an immunoregulatory T cell, and in the generation of PWM-responsive B cells. A model is proposed in which the alterations in atopic cyclic nucleotide metabolism of T-cell helpers could result in abnormalities of immunoregulatory T cells and PWM-recruitable B cells.