Figure 4. The baseline plasma K/T ratio is associated with time to sputum culture conversion.

In persons from Georgia with active TB disease (n = 89), (A) the baseline plasma kynurenine concentration and (B) the baseline plasma K/T ratio were significantly and positively correlated with subsequent time to sputum culture conversion. In persons from South Africa with active TB disease and baseline sputum culture results (n = 71), (C) the baseline plasma kynurenine concentration and (D) the baseline plasma K/T ratio were significantly higher in persons who remained sputum culture positive for M. tuberculosis versus those who did not. For correlation analyses r indicates the Pearson correlation coefficient. Persons from South Africa who remained sputum culture positive for M. tuberculosis versus those who were not were compared using a Wilcoxon rank-sum test (*P ≤ 0.05). The box plots depict the minimum and maximum values (whiskers), the upper and lower quartiles, and the median. The length of the box represents the interquartile range.