Significance Of ESAT6,CFP10and HspX Combination In Differential Diagnosis Active TB Diseatse And Latent Infectiion

Objective:The existing experimental methods can not accurately identify active TB and latent TB, to search for more effective diagnostic strategies for enhancing the efficiency of tuberculin skin test (TST) or substitute for it, and to control or even eradicate tuberculosis(TB), especially latent TB infection(LTBI), antigens of ESAT6and CFP10, which are encoded by RD1and HspX produced under oxygen deprivation, were used to discriminate the active TB and latent TB infection.Methods:Peripheral blood of active TB (n=28) and their close contacts (n=14) and healthy BCG-vaccinated donors (n=11) was collected and to be divided into four groups including initial treated-tuberculosis (IT-TB), retreated-tuberculosis (RT-TB), close contacts (CC,>1year) and heathy BCG-vaccinated donors (HD). ELISPOT was used to detect the IFN-γ secretion T cells after stimulation of ESAT6, CFP10and HspX respectively. ELISA was used to detect the concentration of IFN-y and specific IgG of ESAT6, CFP10and HspX respectively.in blood plasma.Results:The results showed that the three proteins (ESAT6, CFP10and HspX were strongly recognized by peripheral blood mononuclear cells (PBMCs) from the people. Compared with HD and CC, the number of IFN-y secretion T cells which stimulated by ESAT6and CFP10were more in the active TB.(p<0.05) When the HspX was used to stimulate the PBMCs, the spot form units per3×105PBMCs in the HD and CC were similar with the active TB, even more.(p>0.05)The plasma from the donors was added to the96-well plate precoated by the recombinant proteins ESAT6, CFP10and HspX respectively. In the ESAT6precoated team, the results of CC versus IT-TB and RT-TB were statistically significant in all different dilutions except1:100dilution.(p<0.05) The levels of IgG in response to CFP10was no significant difference in the humoral response among the four groups. The optical density of CC was higher than that of other groups in the HspX precoated team. In the1:100dilution, IgG levels of CC was significantly higher than that of HD, IT-TB and RT-TB.(p<0.01) Additionally, the results also had significant difference in CC versus RT-TB in other four different dilutions at1:800,1:1600,1:6400and1:12800.(p<0.05)In the evaluation of total IFN-y concentration of blood plasma, There was significant difference between between HD and RT-TB.(p<0.05)Conclusion:The different groups showed us significant different responses to ESAT6, CFP10and HspX. That people who’s IFN-y secretion cells is more than HD in the ESAT6and CFP10stimulating while who’s is less than HD in the HspX stimulating is TB. That people who’ IgG concentration is less than TB in the ESAT6and CFP10precoated while who’s is more than TB in the HspX precoated is LITB. So the three recombination proteins can be used to differential diagnosis active TB disease and latent infection jointly by ELISPOT and ELISA.