No statistical difference between the levels of IFN-γ in CFP-10 test was observed between the LTBI and NC groups and TB (latent infection + disease) and NC groups (data not shown). Tavares et al.  and Hill et al.  obtained similar results, where the response of IFN-γ levels against CFP-10 was lower than that found against ESAT-6.
When the ROC curve analysis was performed, no statistically significant difference between the groups was observed, even between the TB disease and NC groups (P = 0.076), indicating that the antigen CFP-10 is not a good diagnostic tool for childhood TB. Arend et al.  also observed Ulixertinib in vivo that most TB suspects responded to the antigen ESAT-6, but not to CFP-10. One possible reason for this is that the presence of HLA-DR15, which is the major DR2 subtype, is strongly associated with high responses of CD4+ T cells to the CFP-10 antigen , indicating a greater susceptibility
to infection by M. tuberculosis in populations where this gene is expressed . The absence of expression of this gene in a specific population causes a reduced or even absent response to CFP-10, as different populations differ in antigen processing and recognition of antigenic epitopes by T cells, thereby explaining the genetic polymorphism found among populations  and the differences between the immune responses observed against the same antigen. Other studies corroborate the idea that the host’s immunogenetic Sirolimus nmr background is a decisive factor in the immunological response of specific T lymphocytes to CFP-10 antigen stimuli when it is presented by macrophages or other antigen-presenting cells . It is possible that the epitope recognized by the induced T cells is not presented or presented inefficiently by M. tuberculosis-infected cells. This would explain why the DNA vaccine using CFP-10 antigens protect some species of mice from M. tuberculosis, as was observed by Wu et al. , although the same finding was not produced by Mollenkopf et al.
. Mustafa et al.  argue that the variability of sensitivity and specificity found in tests using CFP-10 as the antigen is determined by factors that are intrinsic to the bacterium, such as the abundance of the protein, PRKACG its subcellular location, post-translational modification, participation in macromolecular complexes and in vivo regulation. They also cite factors relating to the antigen-presenting cell, including location with respect to the phagosome, proteolytic sensitivity and the presence of motifs suitable for interaction with TAP transporters and different MHC alleles. De Meher et al.  found a weak ligation among CFP-10 antigens among bilayers presenting cells, suggesting that this antigen might only remain loosely attached, which corroborates the findings of de Jonge et al. , in which ESAT-6 shows greater T-cell activation compared to the ESAT-6-CFP-10 complex.