Natural killer cell activity, interferon-gamma and antibodies to herpes viruses in patients with Behçet's disease.

Interferon-gamma (IFN-gamma) titres in 20 patients with active Behçet's disease were examined and compared with those of 20 normal donors. Sera from Behçet's disease patients revealed an IFN-gamma increase but no correlation between IFN level and natural killer (NK) activity. The analysis of lymphocyte subsets by monoclonal antibodies registered an increase of CD8+ T subpopulation and cells co-expressing CD8(+)-Leu7a+ markers. Moreover, a high number of cells expressing CD25+ and HLA-DR+ phenotype has been noted in patients with active Behçet's disease. Serological analysis showed a high level of IgG antibodies to HSV-1. The increase of IFN-gamma titre, the high number of activated T cells and the increasing level of IgG antibodies to HSV-1 are important manifestations during the active stage of Behçet's disease. These findings are discussed in relation to the immunopathogenesis of Behçet's disease.