Cytokine concentrations and responses measured with a microarray.

Median background cytokine concentrations (Nil, pg/mL) and cytokine responses (pg/mL) to phytohemagglutinin (Mitogen Response), early secreted antigenic target-6 (ESAT-6 Response), culture filtrate protein 10 (CFP-10 Response), TB7.7 (TB7.7 Response), and combinations of these M. tuberculosis (Mtb) antigens (ESAT-6+CFP-10 Response and ESAT-6+CFP-10+TB7.7 Response) are listed with ranges in parentheses. Cytokine concentrations were measured by a commercial quantitative immuno-microaray (microarray) for patients with culture-confirmed tuberculosis (patients) and subjects at low risk for Mtb exposure (controls). Responses were calculated by subtracting the background cytokine concentration in plasma from blood incubated with saline (Nil) from the cytokine concentration in plasma from blood incubated with mitogen or Mtb antigens. Cytokine responses for some patients and controls were not determined due to poor performance of the respective standard curves. N = 5 or 6 for patients subjects and N = 6 or 7 for controls unless indicated (*n = 4, **n = 5). P values were calculated by Mann-Whitney U Rank Sum test comparing cytokine concentrations or responses for patients with controls. Significant differences (pbold type.