ABSTRACT
BACKGROUND: 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. AIM: 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). SETTINGS AND DESIGN: This cross-sectional study was done at King Khalid University Hospital, Riyadh, Saudi Arabia. MATERIALS AND METHODS: 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 ANALYSIS: Statistical Package for Social Sciences (version 11.5) was used for analysis. RESULTS: 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). CONCLUSION: 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.