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.