Noninferiority of the 4-month regimen to the standard regimen with respect to the primary efficacy end point was not shown. (Funded by the Special Program for Research and Training in Tropical Diseases and others; ClinicalTrials.gov number, NCT00216385.).

The 4-month regimen of rifampin was not inferior to the 9-month regimen of isoniazid for the prevention of active tuberculosis and was associated with a higher rate of treatment completion and better safety. (Funded by the Canadian Institutes of Health Research and the Australian National Health and Medical Research Council; ClinicalTrials.gov number, NCT00931736 .).

Background Host-related and environment-related factors have been shown to play a role in the development of tuberculosis (TB), but few studies were carried out to identify their respective roles in resource-poor countries.

No abstract

Activation of Th1 lymphocytes, IFN‐γ production and macrophage activation are crucial in defense against Mycobacteria. In developing countries, Th2 activation and IL‐4 production have been associated in vitro with tuberculosis and with poor clinical outcome after treatment. Serological markers of Th1 [soluble lymphocyte activation gene (LAG)‐3] and Th2 (IgE, solubleCD30, and CCL22/macrophage‐derived chemokine) activity were measured in 414 HIV‐negative tuberculosis patients from The Gambia and Guinée and in 414 healthy household and community controls. Measurements were repeated during treatment to assess the effect of therapy on Th1/Th2 ratio. At diagnosis, sLAG‐3 levels were lower in patients than in community controls (p<0.0001), but were higher in household controls exposed to contact with patients than in community controls (p<0.0001). In comparison with community controls, patients had consistently higher levels of IgE, sCD30, and CCL22 (p<0.0001), whereas household controls had lower levels of indicators of Th2 activity (p<0.0001). After treatment, cured patients had higher levels of Th1 (p<0.0001) and lower levels of Th2 (p<0.0001) activity than patients who were not successfully treated or interrupted therapy. In Africa, tuberculosis is associated with low Th1 and high Th2 activity in vivo, whereas close exposure to tuberculosis is associated with a high Th1/Th2 ratio. Patients with favorable outcome after treatment exhibit a higher Th1/Th2 ratio compared to patients with poor clinical outcome.