Dynamics and proliferative capacities of CD8+CD28+TCRαß+CD62Lhigh T-cell subsets in healthy and asthmatic subjects.

Adhesion molecules, as such, play essential roles in T-cell transendothelial extravasation during inflammation. A better understanding of the mechanisms underlying this process may be of value in the management of asthma. The present study employed Magnetic-Activated Cell Sorting (MACS) to isolate human CD8+ T lymphocytes from peripheral blood of asthma patients and controls. The cells were flow cytometrically assessed to evaluate surface expression of an adhesion molecule, L-selectin (CD62L) on the surface of CD8FoxP3-/bright T cell subsets and its response to inflammatory cytokines. We showed that CD8+CD28+TCRαß+CD62LhighFoxP3bright T cells were deficient in blood of some asthma patients but abundant in others. After co-stimulation of CD8+ T cells with anti-CD3/CD28 in combination with IL-2 and IL-10 or TGF-ß, the frequencies of CD8+CD28+TCRα/ß+CD62Lhigh T cells in the group of patients were lower than at baseline. Our data indicate that L-selectin expression is regulated by inflammatory cytokines. Overall, these data reveal that asthma phenotypes may be further stratified into micro subtypes with distinct cellular and molecular characteristics, supporting the concept of asthma endotypes.

Interleukin-2-mediated stat-5 expression levels in CD8+CD25+ regulatory T cells: the relevance for asthma.

Preliminary studies demonstrated the potential role of CD8+CD25+ T regulatory cells (Tregs) in asthma. However, published data with regard to the relevance of signaling pathways that govern Tregs homeostasis are limited and conflicting. The first aim of this study was to characterize the phosphorylation of STAT-5 in CD8+CD25+ Tregs. The second aim was to investigate the ability of CD8+CD25+ Tregs from patients and controls to respond to interleukin (IL)-2 treatment in vitro. Twenty-five healthy subjects (NC) and 50 patients with either severe (SA) or mild-moderate (MA) asthma were enrolled in the study. STAT-5 phosphorylation was detected in purified CD8+CD25+ Tregs from healthy and asthma subjects, indicating that STAT-5 has a role in their pathobiology. At baseline, asthmas had either significantly lower [(SA=4.5±5% vs NC=26±25%, P < 0.001) and (MA=10±7.5% vs NC=26±25%, P < 0.001)] or higher [(SA=54±58.5% vs 26±25%, P < 0.01) and (MA=71±74.5% vs 26±25%, P < 0.01) proportion of Tregs expressing pSTAT-5 than controls. In contrast to healthy subjects, CD8+CD25+ Tregs from asthma subjects had either increased (pSTAT-5high) or decreased (pSTAT-5low) phosphorylated STAT-5 levels within individual cells. These data suggest that the alteration in STAT5 phosphorylation level might be associated with asthma and is a potential molecular basis of skewed CD8+CD25+ Treg differentiation. IL-2 treatment of cells from severe asthma subjects increased the proportion of cells expressing high level of pSTAT-5 while it decreased the proportion of those expressing low level of pSTAT-5. Strikingly, IL-2 increased the proportions of both subsets from mild-moderate asthma subjects. These findings demonstrate that altered IL-2-mediated STAT-5 phosphorylation within individual circulatory CD8+CD25+ Tregs may be associated with asthma and disease severity.

The relative values of CD8+CD25+Foxp3brigh Treg cells correlate with selected lung function parameters in asthma.

The study aimed to detect CD8(+)CD25(+)FoxP3(brigh) Tregs and investigate their possible association with selected lung function values. CD8(+)CD25(+)FoxP3(brigh) Tregs were detected by flow cytometry in the peripheral blood of 25 patients with severe asthma (SA), 25 patients with mild-to-moderate asthma (MA), and 25 age-matched healthy donors (NC). The percentages of CD8(+)CD25(+)FoxP3(brigh) Tregs of the patients with severe (3.4 ± 4.55), and mild-to-moderate asthma (7.5 ± 8.15), were markedly lower than those of controls (12.1 ± 13.2). The mean forced expiratory volume in 1 s (FEV1) % predicted value in severe asthma subpopulation was significantly lower (67.05 ± 15.98%) when compared with that of mild-to-moderate asthma subgroup (87.71 ± 16.12%). Interestingly, the percentages of CD8(+)CD25(+)FoxP3(brigh) Tregs correlate with mean peak expiratory flow (PEF)% predicted values in severe (r = 0.7, P <0.01) and mild-to-moderate (r = 0.73, P <0.01) asthma. In contrast, this parameter was positively correlated with FEV1% predicted values in the severe asthmatics only (r = 0.71, P <0.01). In summary, this study establishes a link between the percentage of CD8(+)CD25(+)FoxP3(brigh) Tregs and selected lung function parameters, suggesting that this parameter has potential as a marker for inflammation and airflow obstruction.

Allergy-related changes in levels of CD8+CD25+FoxP3(bright) Treg cells and FoxP3 mRNA expression in peripheral blood: the role of IL-10 or TGF-beta.

There is an increasing body of evidence that alterations of regulatory T (Treg) cell numbers and functions lead to immune disorders. Accordingly, understanding the regulatory mechanisms that maintain peripheral regulatory T (Treg) cell homeostasis is key to the development of effective targeted biologic therapies. We previously demonstrated the effects of IL-10 or TGF-beta on distinct CD8+CD28- T cell subsets in vitro. Allergy-related changes of CD8+CD25+FoxP3(bright)Treg cells and FoxP3 mRNA expression in peripheral blood were assessed by means of multicolor flow cytometry and real-time polymerase chain reaction (RT-PCR). Co-stimulation of CD8+CD25+ T cells with anti-CD3/CD28 in the presence of either IL-10 or TGF-beta increased the frequency of CD8+CD25+FoxP3(bright)Treg cells in patients with asthma and controls. Likewise, CD8+CD25+ T cell activation with anti-CD3/CD28 and TGF-beta increased FoxP3mRNA expression in all groups. Anti-CD3/CD28 and IL-10 appeared to regulate FoxP3 mRNA expression in a phenotype-dependent manner. Specifically, co-stimulation by anti-CD3/CD28 and IL-10 markedly increased FoxP3 mRNA expression in the severe asthma group whereas it had opposite effects on this value in other groups. Taken altogether, these data suggest that IL-10 and TGF-beta may modulate FoxP3 expressions at the protein and mRNA levels in respect to their need for peripheral tolerance.

The effects of interleukin-10 or TGF-beta on anti-CD3/CD28 induced activation of CD8+CD28- and CD8+CD28+ T cells in allergic asthma.

The CD8+CD28- and CD8+CD28+ T cells play a primordial role in peripheral tolerance, but little is known about their implication in allergic asthma. This study was designed to determine the changes in a proportion of human circulatory CD8+ subsets before and after short term culture in the presence of anti-CD3/CD28 and IL-10 or TGF-beta. Flow cytometry analysis revealed increased percentage of CD8+CD28- T cells but decreased percentage of CD8+CD28+ T cells enriched from peripheral blood of adult allergic asthma individuals compared to controls (baseline). In comparison to the baseline, co-stimulation with anti-CD3/CD28 and IL-10 decreased the proportion of CD8+CD28- T cells in severe allergic asthma subjects, whereas it increased this value in mild to moderate asthmatic subjects and controls. Adding TGF-beta decreased the proportion of CD8+CD28- T cells from allergic asthma subjects, whereas it has opposite effects on this subset from controls. IL-10 and TGF-beta had some plethoric effects on FoxP3 expression in anti-CD3/CD28 activated CD8+CD28- T cells. Thus, these findings indicate that a control mechanism involving IL-10 and TGF-beta might be defective in allergic asthma subjects.

Comparison of changes in the percentages of CD8+CD28-TCRalpha beta+ T cell subpopulations in allergic asthma subjects vs controls before and after anti-CD3/anti-CD28/IL-2 stimulation in vitro.

Asthma is a chronic inflammatory disease characterized by the migration of activated T cells into the bronchial mucosa. TGF-beta and IL-10 have proved to regulate airway hyper-responsiveness and leukocytes recruitment to the airways of ovalbumin (OVA) sensitized mice. We examined relative changes in CD8+T cell subpopulations between fifty allergic asthma subjects and twenty five aged-matched healthy adults before and after anti-CD3/CD28 and IL-2 stimulation in the presence of IL-10 or TGF-beta, focusing on CD62L and FoxP3 expressing TCR alpha beta + cells. Severe asthma group had a significantly higher percentage of CD8+ CD28-and CD8+ CD28-TCR alpha beta + CD62L highFoxP3 bright T cells than other groups after enrichment. Compared to the baseline, co-stimulation with either IL-10 or TGF-beta increased the percentage of CD8+CD28-but decrease the percentage of CD8+CD28+T cells within anti-CD3/anti-CD28/IL-2 activated CD8+T cells in all groups. Co-stimulation with anti-CD3/anti-CD28/IL-2 in presence of either IL-10 or TGF-beta decreased the frequencies of CD8+CD28-TCR alpha beta +CD62Lhigh FoxP3 bright T cells in severe asthma subgroup but increased this parameter in other groups. We suggest that altered high level expression of CD62L and FoxP3 on CD8+ CD28-TCR alpha beta + T cell is relevant to allergic asthma. These data have implications for further characterization of CD8+ CD28-TCR alpha beta+ T cell subsets, with special emphasis on their implication in healthy or allergic immune response.

Phenotypic characterization of ex vivo CD4+CD25highCD127low immune regulatory T cells in allergic asthma: pathogenesis relevance of their FoxP3, GITR, CTLA-4 and FAS expressions.

BACKGROUND: CD4+CD25high regulatory T (Treg) cells are crucial for immune homeostasis and peripheral tolerance, but their relevance to allergic asthma has not been fully elucidated. OBJECTIVE: To assess peripheral blood CD4+ T cells, and CD4+CD25highCD127low Treg cells expressing phenotypic markers (FoxP3, GITR, CTLA-4, and FAS) in allergic asthma subjects. MATERIALS AND METHODS: Peripheral blood mononuclear cells were isolated from 60 allergic asthma (AA) subjects and 30 healthy controls (HC). We examined by flow cytometry, the proportion of CD4+ T cells and CD4+CD25highCD127low Treg cells as well as the expression of FoxP3, GITR, CTLA-4, and FAS by CD4+CD25highCD127low Treg cells. Moreover, FOXP3 mRNA expression was measured by quantitative real time polymerase chain reaction (real-time RT-PCR). RESULTS: The absolute number of CD4+CD25highCD127low Treg cells and the percentages of CD4+CD25highCD127low Treg cells expressing one of the four selected markers were significantly lower in allergic asthma subjects compared with controls. We observed no significant decreased absolute CD4+ T cell count in the examined groups compared to the control group. Except for GITR, circulatory CD4+CD25highCD127low Treg cells of severe allergic asthma (SA) subjects showed significantly lower expressions of FoxP3, CTLA-4, and CD95 than did those isolated from mild to moderate asthma (MA) patients. There was no statistically significant difference in the level of mRNA FoxP3 expression in CD4+CD25+ Treg cells between allergic asthma subjects and healthy controls groups, and within the examined groups (p>0.05). CONCLUSIONS: These findings suggest that allergic asthma and the use of glucocorticosteroids are associated with decreased absolute number of circulatory CD4+CD25highCD127low Treg cells and the decreased frequencies of CD4+CD25highCD127low Treg cells expressing one of the four selected markers.

Low frequency of CD8+CD25+FOXP3(BRIGHT) T cells and FOXP3 mRNA expression in the peripheral blood of allergic asthma patients.

The aim of this study is to determine whether frequencies of CD8+CD25+ T cells and FoxP3 messenger RNA (mRNA) expression levels in CD8+ T cells isolated from peripheral blood are related to allergic asthma and disease severity. We enrolled 50 patients with allergic asthma (AA) and 25 healthy control subjects (NC) in our study. The frequencies of CD8+CD25+FoxP3 -/+ T cells were assessed with flow cytometry, and mRNA FoxP3 level in CD8+ T cells was determined with real time polymerase chain reaction (RT-PCR). Asthma patients had fewer CD8+CD25+FoxP3bright T cells [SA (median = 3.4%, IQR = 3.1) vs MA (median = 7.5%, IQR = 4.7)] than controls NC [median = 12.1 %, IQR = 8, P < 0.0001] but more CD8+CD25+FoxP3- T cells [SA (median = 96 %, IQR = 3.1) vs MA (median = 92.5%, IQR = 4.7)] than controls NC [median = 87.9%, IQR = 9.2, P < 0.0001]. FoxP3 mRNA level was significantly decreased in CD8+ T cells of severe asthma patients (median = 0.82, IQR = 0.54) than that of patients with mild to moderate asthma and controls [(median = 2.29, IQR = 4.40) vs (median = 2.11, IQR = 3.2)]. The percentage of FoxP3+ T cells was correlated positively with the percentage of forced expiratory volume in 1 second (FEV1) (r = 0.71, p< 0.01) in patients with severe asthma. The proportion of CD8+CD25+FoxP3bright T cells and the level of FOXP3 gene expression in CD8+ T cells are relevant to allergic asthma and disease severity. The manipulation of FoxP3+CD25+CD8+ T cells may prevent chronic allergic inflammation and improve lung function during an acute allergic asthma exacerbation.