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. 2011 Mar 15;6(3):e17813. doi: 10.1371/journal.pone.0017813

Figure 4. The percentage of ESAT-6 and CFP-10 specific IFN-γ/IL-2 dual positive CD4 T cells does not allow clear distinction between active tuberculosis (A-TB) and non-active disease states (T-TB or latent M. tuberculosis infection).

Figure 4

This is evident from the fact that 7 of 12 (58%) of latently infected subjects had <56% IFN-γ/IL-2 dual positive ESAT-6-specific CD4 T cells The percentage of dual positive CD4 T cells specific for ESAT-6 and CFP-10 was determined as described in figure 2. As compared with PPD specific profiles with higher overall frequencies, robust determination of profiles specific for ESAT-6 and CFP-10 could only be determined if overall frequencies of specific cells were above 0.1% (i.e. in 62.5% of patients with active tuberculosis, 35.7% of individuals with successfully treated disease and 56.0% of latently infected individuals). The stippled line indicates the 56% threshold established for PPD specific T cells.