The effect of Th17 cells on A(H1N1) influenza virus clearance / 中华传染病杂志

ABSTRACT

Objective To investigate the phenotype, frequency of Th17 cells and the association between Th17 cells and viral clearance in patients with H1N1 influenza A. Methods Three groups including 70 confirmed patients with H1N1 influenza A, 30 patients with seasonal influenza as well as 68 healthy subjects as controls were enrolled in this study. The percentages of Th1, Th2, Treg and Th17 lymphocytes in the peripheral blood were determined by intracellular staining and flow cytometry. The levels of interferon-γ (IFN-γ), transforming growth factor-beta (TGF-β),interleukin-6 (IL-6) in plasma and supernatant of the peripheral blood mononuclear cell (PBMC)culture were quantified by enzyme-linked immunosorbent assay (ELISA). Viral load in nasopharyngeal swabs was detected by real time quantitative reverse transcription-polymerase chain reaction (RTPCR). Data were analyzed by one way ANOVA and liner correlation analysis. Results The percentage of Th17 cells in H1N1 influenza A patients was (2. 740±0. 210)%, which the percentage of was significantly decreased compared to healthy subjects (3. 443 ±0. 154)% and seasonal influenza patients (3. 443±0. 277) % (F=4. 242, P＜0. 05); while the percentage of Thl, Th2 and Treg cells were not significantly different among these groups. Moreover, the TGF-β level in plasma of H1N1 influenza A patients was (10±8) ng/mL, which was significantly lower than healthy subjects (43 ±32 ) ng/mL and seasonal influenza patient ( 18 ± 10) ng/mL ( F= 17.72, P＜0.01 ). The TGF-β level in the supernatant of PBMC culture of H1N1 influenza A patients was (782 ± 736) pg/mL, which was significantly lower than healthy subjects (1462±315) pg/mL and seasonal influenza patients (1481 ±348) pg/mL (F=5. 730, P＜0.01). Additionally, the viral clearance period was inversely correlated with the percentage of Th17 cells (r=-0.38, P=0.02). Conclusions The proportion of Th17 cells in patients with H1N1 influenza A is significantly decreased, which is closely correlated with the level of TGF-β. This decrease may results in the delayed viral clearance.