title: CCL22 recruits CD4-positive CD25-positive regulatory T cells into malignant pleural effusion.
abstract: OBJECTIVE
  The aim of this study was to explore the presence of the chemokines CCL22 and CCL17 in malignant pleural effusion, and the chemoattractant activity of these chemokines on CD4-positive CD25-positive Foxp3-positive regulatory T cells infiltrating into the pleural space.
  
  
  METHODS
  The concentrations of CCL22 and CCL17 in both pleural effusions and sera from 33 patients with lung cancer were determined. Flow cytometry was done to determine T lymphocyte subsets in cell pellets of pleural effusion. Pleural cells were analyzed for the expression of CCL22 and CCL17. The chemoattractant activity of CCL22 for regulatory T cells in vitro and in vivo was also observed.
  
  
  RESULTS
  The concentration of CCL22 in malignant pleural effusion was significantly higher than that in the corresponding serum. Pleural fluid from lung cancer patients was chemotactic for regulatory T cells, and this activity was partly blocked by an anti-CCL22, but not by an anti-CCL17 antibody. Intrapleural administration of CCL22 of patients produced a marked progressive influx of regulatory T cells into pleural space.
  
  
  CONCLUSIONS
  Compared with serum, CCL22 seemed to be increased in malignant pleural effusion, and could directly induce regulatory T cell infiltration into the pleural space in patients with malignant effusion.
authors.affiliation: Institute of Respiratory Diseases, First Affiliated Hospital, Guangxi Medical University, Nanning, Guangxi, China.
authors.forename: Xue-Jun
authors.initials: XJ
authors.lastname: Qin
authors.forename: Huan-Zhong
authors.initials: HZ
authors.lastname: Shi
authors.forename: Jing-Min
authors.initials: JM
authors.lastname: Deng
authors.forename: Qiu-Li
authors.initials: QL
authors.lastname: Liang
authors.forename: Jing
authors.initials: J
authors.lastname: Jiang
authors.forename: Zhi-Jian
authors.initials: ZJ
authors.lastname: Ye