Latency in Pulmonary Tuberculosis

The immune responses in latent tuberculosis are poorly understood. While it is difficult to define the onset of latency during natural infection, patients undergoing treatment for tuberculosis are driven into a state of latency or cure. The present study on the effect of 3 and 4 month regimens containing moxifloxacin in sputum smear and culture positive pulmonary tuberculosis (TRC Study number 24) offers us the opportunity to study definitive immune responses pre and post treatment. We will evaluate a variety of innate and adaptive immune responses in patients before and after treatment and our study will compare the differences in immuno-phenotype (eg. Markers of T, B and NK cell activation, proliferation and regulatory phenotype) and function (eg. Production of cytokines, proliferative responses to TB antigens) at different time points following treatment. In addition, since a small percentage of patients will undergo relapse following treatment, the kinetics of immune responses in these patients will used to assess immunological predictors of relapse in tuberculosis.