We found that health controls with grade 1 had lower IFN-γ response to any stimuli, then IFN-γ response increased markedly 12–50 fold in grade 2 of patients with PTB, IFN-γ declined gradually about 20% in grade 3 and then slightly rose about 30% in grade 4, finally decreased 10–50 fold to be very low level in grade 5 which represented severe cavitary PTB, the change pattern of IFN-γ with severe cavities of TB was shown in Fig 12 in bar graph and Fig 13 in line graph. The gene discussed is IFNG; the disease is tuberculosis.