title: Frequency, suppressive capacity, recruitment and induction mechanisms of regulatory T cells in sinonasal squamous cell carcinoma and nasal inverted papilloma.
abstract: BACKGROUND
  Sinonasal squamous cell carcinoma (SSCC) and nasal inverted papilloma (NIP) represent the predominant type of malignant and benign tumors in sinonasal tract, respectively. CD4+ CD25+ Foxp3+ natural regulatory T (Treg) cells might play critical role(s) in the suppression of anti-tumor immune response and thus shed light on tumor progression from benign to malignant.
  
  
  OBJECTIVE
  This study aimed to evaluate the frequency and suppressive capacity of Treg cells in SSCC compared to NIP and further to explore the underlying mechanisms.
  
  
  METHODS
  Frequencies of Treg, Th1 and Th2 cells were evaluated by flow cytometry in tissue homogenate and peripheral blood from 31 SSCC patients, 32 NIP patients and 35 normal controls. Treg cells were tested for regulatory function by co-culture with effector T cells. CCR4 and its ligands, CCL22 and CCL17, were analyzed by flow cytometry and Luminex, respectively. The chemoattractant properties of CCR4/CCL22 and CCR4/CCL17 for Treg cells were assessed using the Boyden chamber technique, to elucidate the potential mechanisms of Treg recruitment in tumor microenvironment. Treg cells induction via TGF-β was assessed with transwells after local CD4+ Foxp3+ T cells were assessed by immunohistochemistry and TGF-β concentration was measured by Luminex.
  
  
  RESULTS
  Tumor-infiltrating Treg cells increased significantly from normal to NIP to SSCC (P ≤ 0.001 for normal vs. NIP and P = 0.004 for NIP vs. SSCC). Significantly elevated frequency and enhanced suppression capacity of circulating Treg cells in SSCC were detected compared to NIP and healthy controls, concomitant with Th1 decrease and Th2 increase. Apparently increased CCL22 attracted CCR4-expressing Treg cells to tumor microenvironment in SSCC, compared to NIP. SSCC produced significantly more TGF-β than NIP and thus possessed greater potential for Treg cell induction.
  
  
  CONCLUSIONS
  Frequency and suppressive capacity of Treg cells enhanced with progression of malignancy from NIP to SSCC. Circulating Treg cells were recruited to tumor tissue via CCR4/CCL22 signalling, whereas tumor-synthesised TGF-β contributed to induction of peripheral Treg cells.
authors.affiliation: Department of Otolaryngology Head and Neck Surgery, Beijing TongRen Hospital, Capital Medical University, Beijing, PR China; Beijing Key Laboratory of nasal diseases, Beijing Institute of Otolaryngology, Beijing, PR China.
authors.forename: Hongfei
authors.initials: H
authors.lastname: Lou
authors.affiliation: Department of Otolaryngology Head and Neck Surgery, Beijing TongRen Hospital, Capital Medical University, Beijing, PR China.
authors.forename: Jugao
authors.initials: J
authors.lastname: Fang
authors.affiliation: Department of Otolaryngology Head and Neck Surgery, Beijing TongRen Hospital, Capital Medical University, Beijing, PR China.
authors.forename: Pingdong
authors.initials: P
authors.lastname: Li
authors.affiliation: Department of Otolaryngology Head and Neck Surgery, Beijing TongRen Hospital, Capital Medical University, Beijing, PR China.
authors.forename: Weiguo
authors.initials: W
authors.lastname: Zhou
authors.affiliation: Beijing Key Laboratory of nasal diseases, Beijing Institute of Otolaryngology, Beijing, PR China.
authors.forename: Yang
authors.initials: Y
authors.lastname: Wang
authors.affiliation: Beijing Key Laboratory of nasal diseases, Beijing Institute of Otolaryngology, Beijing, PR China.
authors.forename: Erzhong
authors.initials: E
authors.lastname: Fan
authors.affiliation: Beijing Key Laboratory of nasal diseases, Beijing Institute of Otolaryngology, Beijing, PR China.
authors.forename: Ying
authors.initials: Y
authors.lastname: Li
authors.affiliation: Beijing Key Laboratory of nasal diseases, Beijing Institute of Otolaryngology, Beijing, PR China.
authors.forename: Hong
authors.initials: H
authors.lastname: Wang
authors.affiliation: Beijing Key Laboratory of nasal diseases, Beijing Institute of Otolaryngology, Beijing, PR China.
authors.forename: Zhongyan
authors.initials: Z
authors.lastname: Liu
authors.affiliation: Sections of Pulmonary & Cardiology, University of Illinois at Chicago, Chicago, Illinois, United States of America.
authors.forename: Lei
authors.initials: L
authors.lastname: Xiao
authors.affiliation: Department of Otolaryngology Head and Neck Surgery, Beijing TongRen Hospital, Capital Medical University, Beijing, PR China.
authors.forename: Chengshuo
authors.initials: C
authors.lastname: Wang
authors.affiliation: Department of Otolaryngology Head and Neck Surgery, Beijing TongRen Hospital, Capital Medical University, Beijing, PR China; Beijing Key Laboratory of nasal diseases, Beijing Institute of Otolaryngology, Beijing, PR China.
authors.forename: Luo
authors.initials: L
authors.lastname: Zhang
mesh_terms: D000328:Adult; D000368:Aged; D002294:Carcinoma, Squamous Cell / Q000276:immunology* / Q000473:pathology; D054414:Chemokine CCL17 / Q000276:immunology; D054422:Chemokine CCL22 / Q000276:immunology; D005260:Female; D006801:Humans; D008297:Male; D008444:Maxillary Sinus Neoplasms / Q000276:immunology* / Q000473:pathology; D008875:Middle Aged; D009298:Nasal Polyps / Q000276:immunology* / Q000473:pathology; D050378:T-Lymphocytes, Regulatory / Q000276:immunology* / Q000473:pathology; D016212:Transforming Growth Factor beta / Q000276:immunology; D059016:Tumor Microenvironment / Q000276:immunology*
chemical_list: C106230:CCL17 protein, human; C515482:CCL22 protein, human; D054414:Chemokine CCL17; D054422:Chemokine CCL22; D016212:Transforming Growth Factor beta