Natural killer cell activity in multidrug-resistant pulmonary tuberculosis.

BACKGROUND

Multidrug-resistant pulmonary tuberculosis (MDRTB), a major problem in developing countries, may result from either insufficiency of host cellular immune response or mycobacterial mechanisms which has been more intensively investigated so far.

OBJECTIVES

The aim of the study was to investigate natural killer cell activity (NKA) and T lymphocyte subsets in HIV- patients with secondary MDRTB.

METHODS

20 male patients with MDRTB (mean age 38 +/- 8 years), 15 nonresistant tuberculosis male patients (NRTB) (mean age 36 +/- 11 years) and 12 healthy male controls (mean age 35 +/- 8 years) were included. The percentages of CD3+, CD4+, CD8+, CD25+, CD11b+ and CD16+56+ cells were measured by flow-cytometric analysis of peripheral blood lymphocytes (PBL). NKA was evaluated using the anticandidal index method.

RESULTS

The mean tuberculin response was higher in MDRTB and NRTB patients compared to controls (15.4 +/- 3.8, 15.1 +/- 3.3 and 10.9 +/- 2.8 mm, respectively; p < 0.001). There was no significant correlation between PPD response and PBL subsets or NKA. The percentages of both CD3+ and CD3+CD4+ T lymphocytes were significantly lower in MDRTB (62.4 +/- 12.1 and 33.9 +/- 9.0%) compared to NRTB (70.8 +/- 7.5 and 42.9 +/- 8.6%; p < 0.05). Patients with MDRTB had significantly lower NKA compared to NRTB and controls (30.9 +/- 11.3, 49.7 +/- 15.5 and 40.0 +/- 8.5%, respectively; p < 0.01).

CONCLUSION

This reduction in NKA may suggest a role for impaired NK function in the pathogenesis of MDRTB in HIV- patients.