Immunophenotypic characterisation of peripheral T lymphocytes in pulmonary tuberculosis

The cellular immune response plays an important role in determining the outcome of infection and disease in Mycobacterium tuberculosis. Many studies of these disease interactions yield contradictory results.

This study aims at determining the changes that take place in the subpopulations of T lymphocytes in the blood of patients with pulmonary tuberculosis (TB).

This cross-sectional study was done at King Khalid University Hospital, Riyadh, Saudi Arabia.

Flow cytometry was used to determine the absolute numbers and percentages of T CD3, T CD4, T CD8, T CD19 and natural killer (NK) T cells in 54 patients with active pulmonary TB before the commencement of treatment and in 25 healthy PPD negative volunteers.

Statistical Package for Social Sciences (version 11.5) was used for analysis.

There were significant differences in the values of CD3, CD4 and NK T cells among the groups. The numbers of CD3 and CD4 cells were lower in subjects than in controls [1091.9 +/- 321.4 vs. 1364.6 +/- 251.2; P < 0.001 and 639.8 +/- 285 vs. 822 +/- 189.9; P < 0.004, respectively] while numbers of NK T cells were much higher in patients than in controls (410.7 +/- 286 vs. 182.3 +/- 140; P < 0.001). The numbers of CD8 cells were not significantly changed with disease (609 +/- 233.5 in subjects and 613.4 +/- 170.3 in controls P = 0.761).

There are significant changes in the cellular immune response particularly affecting the CD3, CD4 and NK T cells with the development of pulmonary TB. Therefore, further studies of these changes may have important implications on the development of diagnostic tools, vaccines and treatment modalities.