Abstract:
Objective：To observe and explore the significance and changes of Th17 cells in peripheral blood and ratio of sIgA/ALB in human saliva.
Methods：A total of 100 RRTIs children were divided into two groups: acute group(n=50) and remission group(n=50).Another 50 normal healthy children were included as the control group. The expression rate of Th17 cells was detected by flow cytometry, the expression rate of sIgA in saliva was detected by enzymatic-reader,and the ALB was detected by immune turbidity method.
Results：The circulating frequencies of Th17 cells in acute and remission group were higher than those in healthy control group(P<0.05), while those in acute group were higher than those in remission group(P<0.05).There were significantly difference in these groups(P<0.05). The circulating frequencies of Th17 cells were positively correlated with the severity of recurrent respiratory tract infection(P<0.05). The ratio of sIgA and serum albumin in saliva in healthy control group was significantly higher than that of acute group and remission group in RRTIs children(P<0.05),but that was no significant difference between acute and remission group(P>0.05).
Conclusion：The circulating frequencies of Th17 cells in RRTIs children are increased, and are positively correlated with the severity of the RRTIs. The function of mucosal immune function in RRTIs children is low, so enhancing the immune function of the respiratory tract can fundamentally reduce the attack of RRTIs.

Key words: Recurrent respiratory tract infections(RRTIs), Th17 cells, SIgA in saliva, Immune, Child