Smear-negative pulmonary tuberculosis and lymphocyte subsets

To correlate and quantitate lymphocyte subsets with clinically diagnosed smear-negative pulmonary tuberculosis and severity of disease.

Case-control study.

Military Hospital and Armed Forces Institute of Pathology Rawalpindi. 1999-2000.

Freshly diagnosed, well-characterized smear-negative patients (n=15) of pulmonary tuberculosis were selected. Non-induced three-consecutive negative smears of sputum with simultaneous culture for AFB for 6-8 weeks, positive Mauntoux test (Z10 mm), blood complete picture with ESR and chest x-rays were done. Selected panel of monoclonal antibodies against specific CD markers were used. Statistical analysis done by student t-test or Mann-Whitney rank-sum test with the help of Sigma State software.

Hemoglobin and total lymphocyte counts were significantly reduced whereas total leukocyte counts with absolute neutrophil counts were increased. Fraction of CD4+ and CD8+ T lymphocytes with HLA-DR expression was reduced while no significant change in rest of the TB and NK lymphocytes.

Low hemoglobin level, high neutrophil count and low total lymphocytes suggest possible direct relationship with extent of disease. The number of activated CD4+, CD8+, ab and gd TCR T cells have tendency to increase during Mycobacterium infection. This seems to have a potential of being a good, non-invasive prognostic indicator for patients with pulmonary tuberculosis.