Abstract: Objective To study Th17 cell subsets, serum IL-17A and IL-23 level and analyze their clinical significance in the patients with pulmonary tuberculosis (PTB).Methods Collected 47 PTB cases from Dongguan Hospital for Prophylaxis and Treatment of Chronic Disease in June 2012 to June 2013, of which 19 patients were treated with the conventional anti-TB therapy within 3days, 28 patients were 28-35days. 19 cases were sputum smear-positive, and 28 cases were sputum smear-negative. Twenty-six healthy individuals were selected as control. The frequency of Th17 cell subsets in PBMC was measured by flow cytometry (FCM). Serum IL-17A and IL-23 levels were detected by ELISA. Their correlation was analyzed.Results The frequence of Th17 cell subsets in peripheral blood of PTB patients (3.18±0.15)％ was significantly lower than that in healthy volunteers (HV) ((5.02±0.21)％,t=7.116,P<0.001). The frequence of Th17 cell subsets in PTB patients was significantly increased from (2.90±0.21)％ to (3.60±0.20)％ after drug treatment (t=2.321, P<0.05), and the frequence of Th17 cell subsets in sputum smear-positive PTB patients (2.51±0.20)% was significantly lower than that in sputum smear-negative patients ((3.64±0.21)%,t=4.185,P<0.001). Serum IL-17A levels in PTB patients (71.24±8.03)pg/ml were significantly higher than those on HV groups ((30.46±2.24)pg/ml, t=2.588, P<0.05), but serum IL-23 levels in PTB patients (26.02±1.35)pg/ml were significantly lower than those in HV groups ((35.06±2.66) pg/ml, t=3.511, P<0.05). Serum IL-17A levels in PTB patients were significantly decreased from (77.36±4.29) pg/ml to (65.50±3.35) pg/ml (t=2.678, P<0.05), but serum IL-23 levels in PTB patients were significantly increased from (24.10±1.22) pg/ml to (30.06±2.63) pg/ml (t=2.716, P<0.05). Serum IL-17A levels in sputum smear-positive PTB patients (80.28±4.16) pg/ml were significantly higher than those in sputum smear-negative patients ((65.32±3.37) pg/ml, t=2.678 P<0.05), but serum IL-23 levels in sputum smear-positive PTB patients (23.65±1.21) pg/ml were significantly higher than those in sputum smear-negative patients ((29.75±2.35) pg/ml, t=3.143,P<0.05). There was positive correlation between Th17 cell subsets and serum IL-23 or IL-17A levels in PTB patients (r=0.324, P<0.05; r=0.215, P<0.05), but there was no correlation between serum IL-23 and IL-17A levels in PTB patients (r=0.078, P>0.05).Conclusion Th17 cell subsets, IL-17A and IL-23 may play different role during PTB development.