Phenotypically activated gamma delta T lymphocytes in the peripheral bloodof patients with tuberculosis

Surface molecules with the potential relevance for resistance against Mycob acterium tuberculosis were investigated. The expression of lymphocyte funct ion antigen-1, very late antigen (VLA)-4, L-selectin, intercellular adhesio n molecule (ICAM)-1, major histocompatibility complex class II, Fas, and CD 40 on alpha beta T cells, gamma delta T cells, NK cells, and monocytes of h ealthy donors and patients with tuberculosis were analyzed. A high activati on status of gamma delta T cells and increased levels of soluble ICAM-1 in plasma of patients with tuberculosis versus healthy individuals was detecte d. Tuberculosis patients with and without an underlying systemic disease co uld be segregated by differential expression of VLA-4 and ICAM-1 on gamma d elta T cells and on monocytes. The composition of peripheral blood mononucl ear cells varied slightly, whereas the proportion of monocytes decreased si gnificantly in patients with tuberculosis, compared with healthy controls. The activation phenotype of peripheral gamma delta T cells in patients with tuberculosis emphasizes the role of these T cells in controlling the infla mmatory process during tuberculosis and perhaps other microbial infections.