Diminished spontaneous and antigen - specific frequencies of Tfh subsets in PTB and LTB.

<p>Whole blood from PTB and LTB individuals was stimulated with PPD, CFP-10, ESAT-6 and anti-CD3 for 6 h, and the frequencies of (A) CD4⁺ CXCR5⁺ PD-1⁺ ICOS⁻; (B) CD4⁺ CXCR5⁺ PD-1⁻ ICOS⁺ and (C) CD4⁺ CXCR5⁺ PD-1⁺ ICOS⁺ T cells were estimated by flow cytometry. Spontaneous frequencies are shown as scatter plots and stimulated frequencies as bar graphs. The bars represent geometric means and 95% confidence intervals. Spontaneous frequencies are shown as raw frequencies and the stimulated frequencies are shown as net frequencies with the spontaneous frequency subtracted. <i>P</i> values were calculated using the Mann-Whitney U test.