CD4+CD25+FoxP3+调节T细胞抑制肺结核患者特异细胞免疫

  目的 了解结核患者外周血中CD4+CD25+FoxP3+调节T细胞在抑制结核患者结核特异细胞免疫反应中的作用。 方法 使用细胞分离、流式细胞分析、细胞增殖和细胞因子测定等方法,比较结核患者及健康正常人群外周血中CD4+CD25+FoxP3+调节T细胞的量及功能特征的差异。 结果 结核患者外周血中CD4+CD25+FoxP3+调节T细胞数占CD4+细胞总数的比例显著高于健康正常人群;在BCG及ESAT-6的刺激下,结核患者外周血单个核细胞增殖能力和产生γ-干扰素的能力比健康正常人群明显增强。在BCG刺激下,结核患者外周血CD4-细胞产生γ-干扰素(1289.62±519.01)及白介素-10(1045.40±534.12)的能力比结核患者外周血BPMCs细胞产生γ-干扰素(624.50±261.13)及白介素-10(377.00±249.56)的能力显著增强(均p<0.05);在BCG及ESAT-6的刺激下,结核患者外周血CD4+CD25+调节T细胞显著抑制结核患者外周血CD4+CD25-细胞产生γ-干扰素及白介素-10。 结论 结核患者CD4+CD25+FoxP3+调节T细胞数量增多,抑制结核患者结核特异细胞免疫反应功能增强,可能与结核的发生、发展及转归有密切关系。     

CD4(+) T cell clones producing both interferon-gamma and interleukin-10 predominate in bronchoalveolar lavages of active pulmonary tuberculosis patients.

The pattern of cytokine production in T cell clones derived from bronchoalveolar lavages (BAL) of active pulmonary tuberculosis (TB) patients was analyzed in clones obtained by limiting dilution procedures which expand with high efficiency either total T lymphocytes, independently of their antigen-recognition specificity, or Mycobacterium tuberculosis-specific T cells. BAL-derived clones, representative of CD4(+) cells from five patients with active TB, produced significantly higher amounts of IFN-gamma than BAL-derived CD4(+) clones from three inactive TB donors or four controls (with unrelated, noninfectious pathology). Average IL-4 and IL-10 production did not differ significantly in the three groups. Although these data suggest a predominant Th1 response to M. tuberculosis infection in the lungs, the majority of BAL-derived CD4(+) clones produced both IFN-gamma and IL-10 and the percentage of clones with this pattern of cytokine production was significantly higher in clones derived from BAL of active TB patients than from controls. Only rare clones derived from peripheral blood (PB)-derived CD45RO(+) CD4(+) T cells of both patients (nine cases) and controls (four cases) produced both IFN-gamma and IL-10; instead, the IL-10-producing clones derived from PB T cells most often also produced IL-4, displaying a typical Th2 phenotype. Higher average amounts of IFN-gamma and IL-10 were produced by BAL-derived CD8(+) clones of four active TB patients than of four controls, although the frequency of CD8(+) clones producing both IFN-gamma and IL-10 was lower than that of CD4(+) clones. The M. tuberculosis-specific BAL-derived T cell clones from three active TB patients were almost exclusively CD4(+) and produced consistently high levels of IFN-gamma often in association with IL-10, but very rarely with IL-4. Unlike the BAL-derived clones, the M. tuberculosis-specific clones derived from PB CD45RO(+) CD4(+) T cells of three different active TB patients and two healthy donors showed large individual variability in cytokine production as well as in the proportion of CD4(+), CD8(+), or TCR gamma/delta(+) clones. These results indicate the predominance of CD4(+) T cells producing both the proinflammatory cytokine IFN-gamma and the anti-inflammatory cytokine IL-10 in BAL of patients with active TB.     

CD4(+)CD25(+)FoxP3(+) regulatory T cells suppress Mycobacterium tuberculosis immunity in patients with active disease

CD4(+)CD25(+) regulatory T cells (Treg) play a central role in the prevention of autoimmunity and in the control of immune responses by down-regulating the function of effector CD4(+) or CD8(+) T cells. The role of Treg in Mycobacterium tuberculosis infection and persistence is inadequately documented. Therefore, the current study was designed to determine whether CD4(+)CD25(+)FoxP3(+) regulatory T cells may modulate immunity against human tuberculosis (TB). Our results indicate that the number of CD4(+)CD25(+)FoxP3(+) Treg increases in the blood or at the site of infection in active TB patients. The frequency of CD4(+)CD25(+)FoxP3(+) Treg in pleural fluid inversely correlates with local MTB-specific immunity (p<0.002). These CD4(+)CD25(+)FoxP3(+) T lymphocytes isolated from the blood and pleural fluid are capable of suppressing MTB-specific IFN-gamma and IL-10 production in TB patients. Therefore, CD4(+)CD25(+)FoxP3(+) Treg expanded in TB patients suppress M. tuberculosis immunity and may therefore contribute to the pathogenesis of human TB.     

IL-17 and IFN-γ expression in lymphocytes from patients with active tuberculosis correlates with the severity of the disease

Th1 lymphocytes are crucial in the immune response against Mycobacterium tuberculosis. Nevertheless, IFN-γ alone is not sufficient in the complete eradication of the bacteria, suggesting that other cytokines might be required for pathogen removal. Th17 cells have been associated with M. tuberculosis infection, but the role of IL-17-producing cells in human TB remains to be understood. Therefore, we investigated the induction and regulation of IFN-γ and IL-17 during the active disease. TB patients were classified as High and Low Responder individuals according to their T cell responses against the antigen, and cytokine expression upon M. tuberculosis stimulation was investigated in peripheral blood and pleural fluid. Afterwards, the potential correlation among the proportions of cytokine-producing cells and clinical parameters was analyzed. In TB patients, M. tuberculosis induced IFN-γ and IL-17, but in comparison with BCG-vaccinated healthy donors, IFN-γ results were reduced significantly, and IL-17 was markedly augmented. Moreover, the main source of IL-17 was represented by CD4(+)IFN-γ(+)IL-17(+) lymphocytes, a Th1/Th17 subset regulated by IFN-γ. Interestingly, the ratio of antigen-expanded CD4(+)IFN-γ(+)IL-17(+) lymphocytes, in peripheral blood and pleural fluid from TB patients, was correlated directly with clinical parameters associated with disease severity. Indeed, the highest proportion of CD4(+)IFN-γ(+)IL-17(+) cells was detected in Low Responder TB patients, individuals displaying severe pulmonary lesions, and longest length of disease evolution. Taken together, the present findings suggest that analysis of the expansion of CD4(+)IFN-γ(+)IL-17(+) T lymphocytes in peripheral blood of TB patients might be used as an indicator of the clinical outcome in active TB.     

IL-10 down-regulates costimulatory molecules on Mycobacterium tuberculosis-pulsed macrophages and impairs the lytic activity of CD4 and CD8 CTL in tuberculosis patients

Activation of T cells requires both TCR-specific ligation and costimulation through accessory molecules during T cell priming. IFNgamma is a key cytokine responsible for macrophage activation during Mycobacterium tuberculosis (Mtb) infection while IL-10 is associated with suppression of cell mediated immunity in intracellular infection. In this paper we evaluated the role of IFNgamma and IL-10 on the function of cytotoxic T cells (CTL) and on the modulation of costimulatory molecules in healthy controls and patients with active tuberculosis (TB). gamma-irradiated-Mtb (i-Mtb) induced IL-10 production from CD14(+) cells from TB patients. Moreover, CD3(+) T cells of patients with advanced disease also produced IL-10 after i-Mtb stimulation. In healthy donors, IL-10 decreased the lytic activity of CD4(+) and CD8(+) T cells whereas it increased gammadelta-mediated cytotoxicity. Furthermore, we found that the presence of IL-10 induced a loss of the alternative processing pathways of antigen presentation along with a down-regulation of the expression of costimulatory molecule expression on monocytes and macrophages from healthy individuals. Conversely, neutralization of endogenous IL-10 or addition of IFNgamma to either effector or target cells from TB patients induced a strong lytic activity mediated by CD8(+) CTL together with an up-regulation of CD54 and CD86 expression on target cells. Moreover, we observed that macrophages from TB patients could use alternative pathways for i-Mtb presentation. Taken together, our results demonstrate that the presence of IL-10 during Mtb infection might contribute to mycobacteria persistence inside host macrophages through a mechanism that involved inhibition of MHC-restricted cytotoxicity against infected macrophages.     

肺结核患者外周血不同T淋巴细胞亚群中白细胞介素-9产生细胞比例的研究

目的 探讨肺结核病(tuberculosis,TB)患者外周血不同T淋巴细胞亚群中白细胞介素(interluekin,IL)-9产生细胞比例的变化.方法 采集26例活动期肺TB患者(TB组)和23例健康志愿者(HD组)外周血样本,加刺激剂佛波醇酯(PMA)和钙离子霉素(IM),以及阻断剂莫能霉素作用6h后,用荧光标记单克隆抗体作T细胞亚型表面分子和胞内细胞因子染色,流式细胞仪检测不同T淋巴细胞亚群中分泌IL-9细胞的比例.结果 CD3+总T细胞中产生IL-9的细胞比例在TB组和HD组分别为0.32％和0.35％,在CD4+ αβ T细胞中分别为0.21％和0.22％,在CD8+ αβ T细胞中分别为0.35％和0.32％,差异均无统计学意义(P＞0.05).而在γδ T细胞中产生IL-9细胞的比例,TB组(2.93％)高于HD组(1.07％),差异有统计学意义(P＜0.05).结论 与HD组比较,TB患者CD4+T细胞和CD8+T细胞中IL-9产生细胞的比例无明显改变,而γδ T细胞中分泌IL-9细胞比例显著增加.     

High IL-10 production by aged AIDS patients is related to high frequency of Tr-1 phenotype and low in vitro viral replication

This work aims to elucidate the effects of age and HIV-1 infection on the frequency and function of T cell subsets in response to HIV-specific and non-specific stimuli. As compared with the younger AIDS group, the frequencies of naive and central memory T cells were significantly lower in aged AIDS patients. Although there was also a dramatic loss of classical CD4(+)FoxP3(+)CD25(+)Treg cells in this patient group, high frequencies of IL-10-producing CD4(+)FoxP3(-) T cells were observed. In our system, the increased production of IL-10 in aged AIDS patients was mainly derived from Env-specific CD4(+)FoxP3(-)CD152(+) T cells. Interestingly, while the blockade of IL-10 activity by monoclonal antibody clearly enhanced the release of IL-6 and IL-1β by Env-stimulated PBMC cultures from aged AIDS patients, this monoclonal antibody enhanced in vitro HIV-1-replication. In conclusion, HIV infection and aging undoubtedly contribute synergistically to a complex immune dysfunction in T cell compartment of HAART-treated older HIV-infected individuals.     

Altered homeostasis of CD4(+) FoxP3(+) regulatory T-cell subpopulations in systemic lupus erythematosus

The role of naturally occurring regulatory T cells (Treg), known to be phenotypically heterogeneous, in controlling the expression of systemic lupus erythematosus (SLE) is incompletely defined. Therefore, different subpopulations of CD4(+) FoxP3(+) Tregs in patients with active or inactive SLE were investigated and compared with those of healthy subjects and patients with ankylosing spondylitis (AS). Characterization of different subsets of circulating CD4(+) FoxP3(+) Tregs was examined using flow cytometry. CD4(+) CD25(high) T cells were sorted and examined for suppressive activity in vitro. The results showed first that a significant decrease in the frequency of CD4(+) CD25(high) FoxP3(+) T cells was present in patients with active SLE (n = 58), compared with healthy controls (n = 36) and AS patients (n = 23). In contrast, the frequencies of CD25(low) FoxP3(+) and CD25(-) FoxP3(+) CD4(+) T cells were significantly increased in patients with active SLE by comparison with the control subjects. The elevation of these two putative Treg subpopulations was associated with lower plasma levels of complement C3 and C4 in patients with SLE. In addition, the ratios of the three subsets of CD4(+) FoxP3(+) Tregs versus effector T cells (CD4(+) CD25(+) FoxP3(-)) were inversely correlated with the titer of anti-double-stranded DNA IgG in patients with inactive, but not active, SLE. These results suggest that the pathogenesis of SLE may be associated with a defect in the homeostatic control of different Treg subsets.     

Alteration in CD29(high) CD4(+) lymphocyte subset is a common feature of early HIV disease and of active tuberculosis

Peripheral CD4 T-cell depletion has been observed in human immunodeficiency virus (HIV)-negative patients with pulmonary tuberculosis (TB). To investigate more accurately this alteration, we studied peripheral blood CD45RA(+) and CD29(high) CD4 subsets in 79 TB patients with (HIV(+)TB(+)) or without (HIV(-)TB(+)) HIV infection, 85 HIV-infected patients without TB (HIV(+)TB(-)), and 43 healthy controls, all living in West Africa. The high proportion of CD4(+)CD29(high) T cells observed in controls was dramatically decreased in CDC-A stage HIV(+)TB(-) patients. CD45RA(+) CD4(+) T cells were depleted during the CDC-B stage. Both the percentage and the absolute count of CD29(high)CD4(+) T cells were decreased in HIV(-)TB(+) and HIV(+)TB(+) patients versus controls, but CD45RA(+)CD4(+) T cells were not decreased in TB patients without HIV-infection. Although distinct alterations in the CD4(+) T-cell homeostasis are involved in TB(-) versus HIV-infected subjects, our data suggest that the CD29(+)CD4(+) T-cell depletion observed during the early HIV disease contributes to the risk of active TB, by reducing the pool of T cells able to relocalize to the sites of the M. tuberculosis multiplication.     

Interleukin-7 matures suppressive CD127(+) forkhead box P3 (FoxP3)(+) T cells into CD127(-) CD25(high) FoxP3(+) regulatory T cells

We have identified a novel interleukin (IL)-7-responsive T cell population [forkhead box P3 (FoxP3(+) ) CD4(+) CD25(+) CD127(+) ] that is comparably functionally suppressive to conventional FoxP3(+) CD4(+) CD25(+) regulatory T cells (T(regs) ). Although IL-2 is the most critical cytokine for thymic development of FoxP3(+) T(regs) , in the periphery other cytokines can be compensatory. CD25(+) CD127(+) T cells treated with IL-7 phenotypically 'matured' into the known 'classical' FoxP3(+) CD4(+) CD25(high) CD127(-) FoxP3(+) T(regs) . In freshly isolated splenocytes, the highest level of FoxP3 expression was found in CD127(+) CD25(+) T cells when compared with CD127(-) CD25(+) or CD127(+) CD25(-) cells. IL-7 treatment of CD4(+) CD25(+) T cells induced an increase in the accumulation of FoxP3 in the nucleus in vitro. IL-7-mediated CD25 cell surface up-regulation was accompanied by a concurrent down-regulation of CD127 in vitro. IL-7 treatment of the CD127(+) CD25(+) FoxP3(+) cells also resulted in up-regulation of cytotoxic T lymphocyte antigen 4 without any changes in CD45RA at the cell surface. Collectively, these data support emerging evidence that FoxP3(+) T cells expressing CD127 are comparably functionally suppressive to CD25(+) CD127(-) FoxP3(+) T cells. This IL-7-sensitive regulation of FoxP3(+) T(reg) phenotype could underlie one peripheral non-IL-2-dependent compensatory mechanism of T(reg) survival and functional activity, particularly for adaptive T(regs) in the control of autoimmunity or suppression of activated effector T cells.     

Intestinal helminth co-infection has a negative impact on both anti-Mycobacterium tuberculosis immunity and clinical response to tuberculosis therapy

The impact of intestinal helminth infection on Mycobacterium tuberculosis (MTB)-specific immune responses during active tuberculosis (TB) is not known. We investigated the role of intestinal helminth infection in anti-MTB immunity by evaluating both cellular phenotype and cytokine profiles in patients with TB and patients with concomitant TB and intestinal helminth infection (TB + Helm) during TB therapy. Twenty-seven per cent of TB patients enrolled for the study were co-infected with at least one intestinal helminth. At baseline, absolute frequencies of leucocytes, monocytes and eosinophils from TB and TB + Helm patients differed from healthy subjects. Concomitant intestinal helminth infection in TB + Helm patients had a negative impact (P < 0.05) on absolute frequencies of CD3(+), CD4(+), CD8(+), natural killer (NK) T and CD4(+) CD25(high) T cell subsets when compared to either TB patients or healthy controls. Differences in CD4(+) T cell frequencies were accompanied by lower interferon (IFN)-gamma and elevated and sustained interleukin (IL)-10 levels in whole blood (WB) cultures from TB + Helm compared to TB patients. In addition to a depressed anti-MTB immunity, TB + Helm patients also presented with more severe radiological pulmonary disease, with a significant difference (P = 0.013) in the number of involved lung zones at the end of TB treatment. The above data may indicate that concomitant intestinal helminth infection in patients with newly diagnosed TB skews their cytokine profile toward a T helper 2 response, which could favour persistent MTB infection and a more protracted clinical course of the disease.     

T regulatory cells and Th1/Th2 cytokines in peripheral blood from tuberculosis patients

About 10% of people infected with Mycobacterium tuberculosis develop active tuberculosis (TB), and Th1 effector cells and Th1 cytokines play key roles in controlling M. tuberculosis infection. Here, we hypothesise that this susceptibility to M. tuberculosis infection is linked to increased T regulatory (Treg) cells and Th2 cytokines in TB patients. To test this, we recruited 101 participants (71 TB patients, 12 non-TB pulmonary diseases and 18 healthy subjects) and investigated Treg cells and Th1/Th2 cytokines in peripheral blood. CD4⁺CD25⁺ T cells and CD4⁺CD25⁺FoxP3⁺ T cells significantly increased and IL-5 dramatically decreased in TB patients relative to healthy subjects. CD8⁺CD28⁻ T cells, IFN-γ, TNF-α, IL-10 and IL-4 significantly increased in patients with culture and sputum smear-positive pulmonary TB (PTB(+)) compared with healthy subjects. CD4⁺CD25⁺FoxP3⁺ and CD8⁺CD28⁻ T cells significantly decreased in PTB(+) after one month of chemotherapy. CD4⁺, CD4⁺CD25⁺ and CD8⁺CD28⁺ T cells significantly increased in extra-pulmonary TB patients after one month of chemotherapy. These findings suggest that M. tuberculosis infection induces circulating CD4⁺CD25⁺FoxP3⁺ and CD8⁺CD28⁻ T cell expansion, which may be related to the progression of M. tuberculosis infection, and that the balance between effector immune responses and suppression immune responses is essential to control M. tuberculosis infection.     

Abnormal immune responses in persons with previous extrapulmonary tuberculosis in an in vitro model that simulates in vivo infection with Mycobacterium tuberculosis

Persons with previous extrapulmonary tuberculosis have reduced peripheral blood mononuclear cell cytokine production and CD4(+) lymphocytes compared to persons with previous pulmonary tuberculosis or latent tuberculosis infection, but specific defects related to Mycobacterium tuberculosis infection of macrophages have not been characterized. The objective of this study was to further characterize the in vitro immune responses to M. tuberculosis infection in HIV-seronegative persons with previous extrapulmonary tuberculosis. Peripheral blood mononuclear cells were isolated from HIV-seronegative persons with previous extrapulmonary tuberculosis (n = 11), previous pulmonary tuberculosis (n = 21), latent M. tuberculosis infection (n = 19), and uninfected tuberculosis contacts (n = 20). Experimental conditions included M. tuberculosis-infected macrophages cultured with and without monocyte-depleted peripheral blood mononuclear cells. Concentrations of interleukin 1β (IL-1β), IL-4, IL-6, CXCL8 (IL-8), IL-10, IL-12p70, IL-17, CCL2 (monocyte chemoattractant protein 1), tumor necrosis factor alpha (TNF-α), and gamma interferon (IFN-γ) were measured by multiplex cytokine array. When M. tuberculosis-infected macrophages were cocultured with monocyte-depleted peripheral blood mononuclear cells, IFN-γ (P = 0.01), TNF-α (P = 0.04), IL-10 (P < 0.001), and IL-6 (P = 0.03) exhibited similar continua of responses, with uninfected persons producing the lowest levels, followed by extrapulmonary tuberculosis cases, pulmonary tuberculosis controls, and persons with latent M. tuberculosis infection. A similar pattern was observed with CXCL8 (P = 0.04), IL-10 (P = 0.02), and CCL2 (P = 0.03) when monocyte-depleted peripheral blood mononuclear cells from the four groups were cultured alone. Persons with previous extrapulmonary tuberculosis had decreased production of several cytokines, both at rest and after stimulation with M. tuberculosis. Our results suggest that persons who develop extrapulmonary tuberculosis have a subtle global immune defect that affects their response to M. tuberculosis infection.     

Regulation of human CD4(+) alphabeta T-cell-receptor-positive (TCR(+)) and gammadelta TCR(+) T-cell responses to Mycobacterium tuberculosis by interleukin-10 and transforming growth factor beta

Mycobacterium tuberculosis is the etiologic agent of human tuberculosis and is estimated to infect one-third of the world's population. Control of M. tuberculosis requires T cells and macrophages. T-cell function is modulated by the cytokine environment, which in mycobacterial infection is a balance of proinflammatory (interleukin-1 [IL-1], IL-6, IL-8, IL-12, and tumor necrosis factor alpha) and inhibitory (IL-10 and transforming growth factor beta [TGF-beta]) cytokines. IL-10 and TGF-beta are produced by M. tuberculosis-infected macrophages. The effect of IL-10 and TGF-beta on M. tuberculosis-reactive human CD4(+) and gammadelta T cells, the two major human T-cell subsets activated by M. tuberculosis, was investigated. Both IL-10 and TGF-beta inhibited proliferation and gamma interferon production by CD4(+) and gammadelta T cells. IL-10 was a more potent inhibitor than TGF-beta for both T-cell subsets. Combinations of IL-10 and TGF-beta did not result in additive or synergistic inhibition. IL-10 inhibited gammadelta and CD4(+) T cells directly and inhibited monocyte antigen-presenting cell (APC) function for CD4(+) T cells and, to a lesser extent, for gammadelta T cells. TGF-beta inhibited both CD4(+) and gammadelta T cells directly and had little effect on APC function for gammadelta and CD4(+) T cells. IL-10 down-regulated major histocompatibility complex (MHC) class I, MHC class II, CD40, B7-1, and B7-2 expression on M. tuberculosis-infected monocytes to a greater extent than TGF-beta. Neither cytokine affected the uptake of M. tuberculosis by monocytes. Thus, IL-10 and TGF-beta both inhibited CD4(+) and gammadelta T cells but differed in the mechanism used to inhibit T-cell responses to M. tuberculosis.     

In vitro synthesis of interferon-gamma, interleukin-4, transforming growth factor-beta and interleukin-1 beta by peripheral blood mononuclear cells from tuberculosis patients: relationship with the severity of pulmonary involvement

Given the role of cell-mediated immune responses in resistance to mycobacteria, we sought to analyse whether there was a relationship between the severity of pulmonary tuberculosis (TB) and lymphocyte proliferation as well as in vitro cytokine production. To achieve this, 25 untreated TB patients showing mild (n = 5), moderate (n = 9) or advanced (n = 11) pulmonary disease, and 12 age-matched healthy controls (mean+/-SD, 37+/-14.5 years) were studied. Peripheral blood mononuclear cells were cultured for 5 days with 10 microg/ml whole, sonicated Mycobacterium tuberculosis (WSA) or 2.5 microg/ml Concanavalin A (Con A). Supernatants were collected on day 4, from cultures grown with or without WSA, for measurement of interferon-gamma (IFN-gamma), interleukin (IL)-4, IL-1beta and transforming growth factor-beta (TGF-beta). Antigen-specific proliferation was found to be reduced among patients and more profound in those with advanced disease who also displayed a depressed response to Con A. Patients with mild TB showed a preferential production of IFN-gamma over IL-4, gave the highest level of IFN-gamma synthesis upon specific antigen stimulation and showed increased levels of IL-1beta production. Findings in patients with moderate TB appeared compatible with a mixed production of IFN-gamma and IL-4 coexisting with a higher synthesis of TGF-beta, by comparison to patients with mild TB. Advanced disease showed the highest IL-4 and TGF-beta production, with IFN-gamma synthesis readily noticeable, yet decreased in comparison with the other patient groups. Differences in cytokine response according to the amount of lung involvement suggest a role for such mediators in the immunopathogenesis underlying the distinct clinical forms of pulmonary TB, that is a predominant T helper Th)1-like or Th2-like activity in mild or in progressive TB, respectively.     

Reduction of forkhead box P3 levels in CD4+CD25high T cells in patients with new-onset systemic lupus erythematosus

The aim of this study was to quantify and evaluate the forkhead box P3 (FoxP3) expression regulatory T cells in new-onset systemic lupus erythematosus (SLE) patients before and after treatment. Forty-four newly diagnosed and untreated SLE patients, including 24 with active disease (SLEDAI > or = 10) and 20 with inactive disease (SLEDAI < 5), were enrolled in this study. Twenty-one age- and sex-matched healthy volunteers were also included as controls. Peripheral blood samples were collected and mononuclear cells isolated. The expression of CD25 and FoxP3 in CD4(+) T cells were analysed with flow cytometry. CD4(+)CD25(+) (3.95-13.04%) and CD4(+)CD25(high) (0.04-1.34%) T cells in peripheral blood in untreated patients with new-onset active lupus were significantly lower than that in the patients with inactive lupus (7.27-24.48%, P < 0.05 and 0.14-3.07% P < 0.01 respectively) and that in healthy controls (5.84-14.84%, P < 0.05). Interestingly, the decrease in CD4(+)CD25(high) T cells was restored significantly in patients with active lupus after corticosteroid treatment. There was, however, a significantly higher percentage of CD4(+)FoxP3(+) T cells in patients with active (5.30-23.00%) and inactive (7.46-17.38%) new-onset lupus patients compared with healthy control subjects (2.51-12.94%) (P < 0.01). Intriguingly, CD25 expression in CD4(+)FoxP3(+) T cells in patients with active lupus (25.24-62.47%) was significantly lower than that in those patients with inactive lupus (30.35-75.25%, P < 0.05) and healthy controls (54.83-86.38%, P < 0.01). Most strikingly, the levels of FoxP3 expression determined by mean fluorescence intensity in CD4(+)CD25(high) cells in patients with active SLE were significantly down-regulated compared with healthy subjects (130 +/- 22 versus 162 +/- 21, P = 0.012). CD4(+)CD25(high) T cells are low in new-onset patients with active SLE and restored after treatment. Despite that the percentage of CD4(+)FoxP3(+) T cells appear high, the levels of FoxP3 expression in CD4(+)CD25(high) T cells are down-regulated in untreated lupus patients. There is a disproportional expression between CD25(high) and FoxP3(+) in new-onset patients with active SLE.