The importance of CD54 and CD86 costimulation in T cells stimulated with Candida albicans and Dermatophagoides farinae antigens in patients with atopic dermatitis.

A number of studies have demonstrated an increased frequency of allergen-specific T cells producing increased amounts of interleukin-4 (IL-4) and IL-5, but little interferon-y in both the peripheral blood and skin lesions of patients with atopic dermatitis (AD). In this study, to further clarify the characteristics of T cells obtained from AD patients, we examined the dependency of the antigen-specific proliferation of peripheral blood mononuclear cells (PBMC) from AD patients on costimulatory molecules. The antigens used were Candida albicans and Dermatophagoides farinae, for which AD patients show increased levels of IgE antibodies. PBMC from control healthy donors stimulated with these antigens incorporated [3H]-thymidine much more than PBMC from AD patients. The addition of anti-CD54, -CD40, -CD80 and -CD86 monoclonal antibodies to the cultures showed that the PBMC required only CD54 and CD86 for stimulation with C. albicans, but required CD54, CD80 and CD86 for stimulation with D. farinae. Among these monoclonal antibodies, the anti-CD54 antibody suppressed the proliferative responses of most PBMC, most effectively followed by the anti-CD86 antibody. However, there were no significant differences in the requirement for costimulatory molecules of PBMC proliferation stimulated with C. albicans or D. farinae between AD patients and healthy donors. Since many studies have suggested that T-helper type 1 and T-helper type 2 immune responses are different in their dependency on CD80 or CD86 costimulation, our present results suggest that the allergen-specific T cells of AD patients are not completely shifted to a T-helper type 2 subset.