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Open Access Research article

Are CD4+CD25-Foxp3+ cells in untreated new-onset lupus patients regulatory T cells?

Hua-xia Yang1, Wen Zhang1, Li-dan Zhao1, Yang Li1, Feng-chun Zhang1, Fu-lin Tang1, Wei He2 and Xuan Zhang1*

Author Affiliations

1 Department of Rheumatology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, #41 Da-Mu-Cang-Hu-Tong Street, Beijing, 100032, China

2 Department of Immunology, School of Basic Medicine, Peking Union Medical College, and Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences, #5 Dong-Dan-San-Tiao, Beijing, 100005, China

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Arthritis Research & Therapy 2009, 11:R153  doi:10.1186/ar2829


See related editorial by Horwitz, http://arthritis-research.com/content/12/1/101

Published: 12 October 2009

Abstract

Introduction

Our previous study has reported that, in patients with untreated new-onset lupus (UNOL), there was an abnormal increase in the number of CD4+CD25-Foxp3+ T cells that correlated with disease activity and significantly decreased after treatment. However, little is known about the nature of this cell entity. The aim of this study was to explore the nature of abnormally increased CD4+CD25-Foxp3+ T cells in UNOL patients.

Methods

The expressions of surface (CD4, CD25, CD127, chemokine receptor 4 [CCR4], glucocorticoid-induced tumor necrosis factor receptor [GITR], and cytotoxic T lymphocyte-associated antigen 4 [CTLA-4]) and intracellular (Foxp3) molecules as well as cytokine synthesis of peripheral blood mononuclear cells from 22 UNOL patients were analyzed by flow cytometry. The proliferative and suppressive capacities of different T-cell subgroups from UNOL patients were also assessed.

Results

In UNOL patients, the percentages of CD127low/- in CD25high, CD25low, and CD25- subpopulations of CD4+Foxp3+ T cells were 93.79% ± 3.48%, 93.66% ± 2.31%, and 91.98% ± 2.14%, respectively (P > 0.05), whereas the expressions of Foxp3 showed significant differences in CD25high (91.38% ± 2.57%), CD25low (71.89% ± 3.31%), and CD25- (9.02% ± 2.21%) subpopulations of CD4+CD127low/- T cells (P < 0.01). The expressions of surface CCR4, GITR, and CTLA-4 on CD4+CD25-Foxp3+ T cells were significantly less than CD4+CD25+Foxp3+ T cells (P < 0.05). Moreover, unlike CD4+CD25+Foxp3+ T cells, CD4+CD25-Foxp3+ T cells also synthesized interferon-gamma, interleukin (IL)-4, IL-2, and IL-17 (P < 0.05), though less than CD4+CD25+Foxp3- T cells. The suppressive capacity was most prominent in CD4+CD25highCD127low/-, followed by CD4+CD25lowCD127low/-. CD4+CD25-CD127- T cells showed the least suppressive capacity, which was similar to the effector T cells.

Conclusions

CD4+CD25-Foxp3+ T cells in UNOL patients are different from regulatory T cells, both phenotypically and functionally. CD127 is not an appropriate surface marker for intracellular Foxp3 in CD4+CD25- T cells.