The Distribution of ${\gamma}{\delta}$ T Cells in Tuberculous Lymphadenopathy

Background : The antigen-specific receptor on the surface of most peripheral T lymphocytes is a disulfide-linked heterodimer composed of and subunits, noncovalently associated with CD3 polypeptides. Recently, a novel type of CD3-associated heterodimer was described on a T cell subset that does not express CD4 or CD8 molecules. This second type of TCR dimer is composed of chains encoded for by the - and -TCR genes. These cells may exert both cytotoxic and lymphokine producing functions. Although it was reported that some -TCR might recognize an MHC-linked determinant, the funetion or physiologic ligand for this new receptor is not yet clear. It was found that -TCR can react with 65 kD heat shock protein of M. tuberculosis, which suggests the possible protective role of T lymphocytes against tuberculosis. In our previous study, there was neither the increase in number nor the functional activation of T cells in the peripheral blood from patients with pulmonary tuberculosis. Now we report the distribution of T cells in the regional sites of M. tuberculosis infection, especial1y tuberculous lymphadenitis. Methods : Lymph nodes from patients with pathologically-proven tuberculous lymphadenopathy (n=5) and reactive hyperplasia (n=3) were used. Tissues were frozen in liquid nitrogen immediately after removal and stored below . The cryostat sections of these frozen specimens were stained with anti-Leu-4 Ab, Identi-T TCR , and Identi-T . The number of positively stained cells were counted at high power field. Results : The infiltration of T cells was significantly higher in the lymph nodes from patients with tuberculous lymphadenopathy than that with reactive hyperplasia ( vs. ). Conclusion : These results suggest that ) T cells may play a role in the defense against M. tuberculosis infection, especially in the regional sites of infection.