Title: Role of CD4~+CD25~+ regulatory T cells in children with acute immune thrombocytopenic purpura
Abstract: Objective To explore the role of CD4+CD25+ regulatory T cells (Treg) in children with acute immune thrombocytopenic purpura (AITP). Methods 25 patients with AITP were recruited in this study and 30 healthy children without immunologic diseases or infectious disorders were studied as control. Peripheral blood mononuclear cells (PBMC) were isolated by Ficoll density gradient centrifugation and were stained with anti-CD4-PE-Cy5, anti-CD25-FITC, anti- CD62L-PE or anti-FoxP3-PE or anti-CD152-PE monoclonal antibodies. For cell surface staining, all Abs were added and cells were stained for 20 minutes. When performing intracellular staining for FOXP3 or CD152, cell-surface staining was first completed, and then the cells were fixed and permeabilized for intracellular staining. Stained cells were examined by three-color flow cytometric analysis using a FACS Altra cell sorter. The serum levels of transforming growth factor-β (TGF- β) and interleukin-10 (IL-10) were assayed by enzyme-linked immunosorbent assay kits. Results Only about 60% CD4+ CD25+ T cells were positive for FoxP3+, while an overwhelming majority of CD4+CD25hi T cells (over 90%) expressed FoxP3. There were no significant differences in CD4+CD25hi, CD4+ CD25+FoxP3+ , and the ratio of CD4+CD25+FoxP3+ T cells to activated effective CD4+CD25+FoxP3- T cells between AITP group and the control group [(0.95 ± 0.27)% vs (1.08 ± 0.37)%, (4.54 ± 1.31)% vs (5.28 ± 1.52)%, and (0.61 ± 0.26) vs (0.73 ± 0.29), respectively, P 0.05]. The level of TGF-β in AITP group decreased significantly compared with that in normal children ((9.44 ± 2.78) ng / ml vs (25.23 ± 3.42) ng / ml, P 0.05). In contrast, the level of serum IL-10, only measured in five patients, was not different from normal reference value. The percentage of B lymphocyte was significantly higher in AITP group than that in the controlgroup ((19.90 ± 7.42)% vs (12.02 ± 3.82)%, respectively, P 0.05), with no significant differences in proportions of NK cells, CD3+ T cells, and the ratio of CD3+CD4+ to CD3+CD8+ T cells between the two groups ((15.06 ± 8.25)% vs (18.43 ± 7.71)%, (52.64 ± 8.45)% vs (55.53 ± 11.90)%, (0.97 ± 0.37) vs (1.12 ± 0.32), respectively, P 0.05). Conclusions The results suggested that insufficient secretion of TGF-β might be one of the mechanisms that caused immune regulation dysfunction in children with AITP despite normal percentage of Treg cell.
Publication Year: 2009
Publication Date: 2009-01-01
Language: en
Type: article
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