Glucocorticoid induced TNFR-related protein (GITR) as marker of human regulatory T cells: expansion of the GITR+CD25- cell subset in patients with systemic lupus erythematosus

Abstract

Objectives: Regulatory T cells (TREG) represent a T cell subset able to modulate immune response by suppressing autoreactive T-lymphocytes. The evidence of a reduced number and an impaired function of this cell population in autoimmune/ inflammatory chronic diseases led to the hypothesis of its involvement in the pathogenesis of these disorders. Glucocorticoid-induced TNFR-related protein (GITR) is a well known marker of murine TREG cells, but little is known in humans. The aim of this study was to investigate the characteristics of TREG cells in systemic lupus erythematosus (SLE) and the potential role of GITR as marker of human TREG. Methods: Nineteen SLE patients and 15 sex- and age-matched normal controls (NC) were enrolled. CD4+ T cells were magnetic sorted from peripheral blood by negative selection. Cell phenotype was analyzed through flow-cytometry using primary and secondary antibodies and real time polymerase-chain reaction (PCR) using TaqMan probes. Results: The CD25highGITRhigh subset was significantly decreased in SLE patients with respect to NC (0.37±0.21% vs 0.72±0.19%; p<0.05). On the opposite, the CD25-GITRhigh cell population was expanded in the peripheral blood of SLE patients (3.5±2.25 vs 0.70±0.32%, p<0.01). Interestingly, FoxP3 at mRNA level was expressed in both CD25- GITRhigh and CD25highGITRhigh cells, suggesting that both cell subsets have regulatory activity. Conclusions: CD4+CD25-GITRhigh cells are increased in SLE as compared to NC. The expression of high level of GITR, but not CD25, on FoxP3+ cells appears to point to a regulatory phenotype of this peculiar T cell subset

Gitr-Expressing Regulatory T-Cell Subsets are Increased in Tumor-Positive Lymph Nodes from Advanced Breast Cancer Patients as Compared to Tumor-Negative Lymph Nodes

“…Another important Treg and activated T-cell marker is GITR (9,23) which correlates with CD25 expression. Recently, a novel CD4 Treg population was described and characterized, which is CD25 IowGITR+ CD127+ and exerts suppressor activity (16,20). We used CD25, GITR and CD 127 to analyze CD4 T-cell subsets (Fig.…”

“…GITR+population is distributed in the R1Treg region , but also in the R2 region. GITR+ cells inside gate R2 are CD25 IowGITR +CD127+ cells and can be considered a subset ofTreg cells according to the latest development in Treg subpopulations (16,20). Therefore, we evaluated the number of GITR+ cells inside gate R2 in tumor-positive and tumor-negative lymph nodes and found that also CD25 IowGITR +CD127+ cells are dramatically increased in tumor-positive lymph nodes (Fig.…”

“…CD 127 is also an effector marker, and is downregulated in Treg cells (18,19). A subtype of CD25!owGITWCDl27+ Treg was recently identified and characterized (16,20). According to this data we identified a gating strategy based on CD25, GITR and CD 127 in an attempt to identify 3 subpopulations: effectors, CD25highGITWCDI27-/low and CD25 IowGITR +CDI27' Treg cells.…”