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Journal of Immunology Research
Volume 2014, Article ID 651872, 11 pages
http://dx.doi.org/10.1155/2014/651872
Research Article

Increased Frequency of Circulating Follicular Helper T Cells in Children with Hand, Foot, and Mouth Disease Caused by Enterovirus 71 Infection

1Department of Clinical Laboratory, The First Affiliated Hospital, School of Medicine, Zhejiang University, 79 Qingchun Road, Hangzhou 310003, China
2Department of Clinical Laboratory, Center of Community Health Service of Qingbo Street, Hangzhou 310002, China
3Department of Pathology and Center of Infection and Immunology, The University of Hong Kong, Hong Kong

Received 8 March 2014; Revised 30 April 2014; Accepted 7 May 2014; Published 11 June 2014

Academic Editor: Toshinori Nakayama

Copyright © 2014 Jianping Wu et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Enterovirus 71 (EV71) is a major causative agent of hand, foot, and mouth disease (HFMD) in children. The role of T follicular helper (TFH) cells in EV71-infected children remains unclear in regulating humoral immunity. The frequency of circulating ICO /PD- CXCR5+CD4+ TFH cells in the children with mild and severe EV71 infection and healthy controls (HC) was detected by flow cytometry, respectively. IL-21 and IL-6 mRNA expression and their serum levels, Bcl-6 mRNA expression, and specific neutralizing antibodies against EV71 (NAb-EV71) were measured. In the acute stage of patients with EV71 infection, increased frequencies of circulating TFH cells with ICO and PD- expression in the mild and severe patients were observed, and the positive correlations among the frequencies of circulating TFH cells and the serum levels of IL-21, IL-6, and NAb-EV71 titres were detected, respectively. Moreover, the expressions of IL-6 and IL-21 mRNA in PBMCs from patients were also significantly higher than those of HC. However, further analysis did not reveal any significant differences between mild and severe patients. These data indicate a role of TFH cells and associated cytokines in modulating the humoral response during the pathogenesis of EV71 infection.