Gamma/delta T lymphocytes in Mycobacterium tuberculosis infection.

BACKGROUND

Data on the percentage of gamma/delta T lymphocytes in the peripheral blood of patients infected with Mycobacterium tuberculosis are few and contradictory. The percentage of gamma/delta T lymphocytes in the peripheral blood of tuberculin positive and tuberculin negative patients with Mycobacterium tuberculosis infection and healthy controls was compared.

METHODS

Thirty six patients infected with Mycobacterium tuberculosis and 11 healthy controls were studied. Lymphocytes were separated, cytocentrifuged onto glass microscope slides, and reacted with anti-gamma/delta monoclonal antibody. The percentage of gamma/delta positive cells was determined by microscopic counting of 300 lymphocytes.

RESULTS

No difference was found in the percentage of gamma/delta T lymphocytes between patients and controls. However, when the patients were divided into two groups according to reactivity or non-reactivity in the Mantoux skin reaction a higher percentage of gamma/delta T lymphocytes was found in the peripheral blood of patients with tuberculin anergy than in tuberculin positive patients or controls.

CONCLUSIONS

Higher gamma/delta T cell counts are found in tuberculin negative patients with tuberculosis than in tuberculin positive patients or tuberculin positive controls. The high gamma/delta T cell counts in tuberculin anergic patients may reflect a shift in the immune response in a Th2 direction characterised by increased antibody production and decreased cell mediated responses.