Multifunctional CD4+ T cells correlate with active Mycobacterium tuberculosis infection

Th1 CD4⁺ T cells and their derived cytokines are crucial for protection against Mycobacterium tuberculosis. Using multiparametric flow cytometry, we have evaluated the distribution of seven distinct functional states (IFN‐γ/IL‐2/TNF‐α triple expressors, IFN‐γ/IL‐2, IFN‐γ/TNF‐α or TNF‐α/IL‐2 double expressors or IFN‐γ, IL‐2 or TNF‐α single expressors) of CD4⁺ T cells in individuals with latent M. tuberculosis infection (LTBI) and active tuberculosis (TB). We found that triple expressors, while detectable in 85–90%TB patients, were only present in 10–15% of LTBI subjects. On the contrary, LTBI subjects had significantly higher (12‐ to 15‐fold) proportions of IL‐2/IFN‐γ double and IFN‐γ single expressors as compared with the other CD4⁺ T‐cell subsets. Proportions of the other double or single CD4⁺ T‐cell expressors did not differ between TB and LTBI subjects. These distinct IFN‐γ, IL‐2 and TNF‐α profiles of M. tuberculosis‐specific CD4⁺ T cells seem to be associated with live bacterial loads, as indicated by the decrease in frequency of multifunctional T cells in TB‐infected patients after completion of anti‐mycobacterial therapy. Our results suggest that phenotypic and functional signatures of CD4⁺ T cells may serve as immunological correlates of protection and curative host responses, and be a useful tool to monitor the efficacy of anti‐mycobacterial therapy.     

Glucocorticoid-induced tumour necrosis factor receptor family-related receptor signalling exacerbates hapten-induced colitis by CD4+ T cells

The glucocorticoid-induced tumour necrosis factor receptor family related gene (GITR) has been reported to be expressed on the activated T and CD4(+)CD25(+) regulatory T cells (Treg). Signalling triggered by GITR not only neutralizes the suppressive effect of Treg cells, but also augments activation, proliferation and cytokine production of effector T cells. To test the role of GITR in 2,4,6-trinitrobenzene sulphonic acid (TNBS)-induced colitis - a murine model of mucosal inflammation - TNBS-injected Balb/c mice were treated with agonistic anti-GITR monoclonal antibody (mAb). Anti-GITR treatment increased the death rate compared to rat IgG-treated mice. Typically, death occurred within 4 days after the TNBS injection when the mice were treated with anti-GITR. The mice that survived anti-GITR treatment suffered from severe inflammation in their entire intestines. CD4(+) T-depletion protected the mice from colitis; even an anti-GITR effect was not apparent. In contrast, CD8(+) T depletion showed less protective than did CD4(+) T depletion. Stimulation of GITR enhanced the production of proinflammatory cytokines including interferon (IFN)-gamma, tumour necrosis factor (TNF)-alpha, interleukin (IL)-6 and IL-12. It also enhanced the humoral response such as serum levels of IgG(2b) and IgA, which was completely dependent on CD4(+) T cells. Taken together, this study demonstrated that GITR signalling on CD4(+) T cells is involved in the development and progress of colitis by enhancing both T helper type 1 (Th1) and Th2 type responses.     

Interferon-gamma and tumour necrosis factor-alpha production by CD4+ T and CD8+ T lymphocytes in AIDS patients with tuberculosis

Tuberculosis (TB) is usually more severe in HIV-infected patients, and the immune derangement found in co-infected patients may differ from that in each isolated disease. Following mitogen stimulation of peripheral blood mononuclear cells (PBMC), interferon (IFN)-gamma and tumour necrosis factor (TNF)-alpha production was evaluated in T cells by flow cytometry, and in culture supernatants by enzyme-linked immunosorbent assay (ELISA) in 33 individuals: 11 AIDS patients with tuberculosis, six asymptomatic HIV-1-infected patients, eight patients with tuberculosis and eight healthy controls. The proportion of CD4+ T lymphocytes expressing IFN-gamma did not differ between the groups, whereas a trend towards increased proportions of TNF-alpha-expression in CD4+ T cells was observed in the TB compared to the HIV group, while intermediate values were observed in co-infected patients. Detection of IFN-gamma and TNF-alpha in CD8+ T lymphocytes was higher in TB than in HIV individuals. Co-infected patients presented intermediate values for IFN-gamma, while TNF-alpha detection was similar to that in HIV mono-infection. In conclusion, the proportion of T cells expressing IFN-gamma was relatively preserved in co-infected patients compared to TB patients, while the percentage of T cells expressing TNF-alpha was decreased, mainly in CD8+ T lymphocytes. However, the marked reduction in T lymphocyte numbers in co-infected patients led to a striking reduction of both cytokines in PBMC supernatants, a finding that is consistent with the impaired response to Mycobacterium tuberculosis.     

多参数分析多发性骨髓瘤患者外周血中CD4~+CD25~+调节性T细胞的表达

目的 通过分析CD4+ CD25+ 调节性T细胞(CD4+ CD25+ regulatory T cells,CD4+ CD25+ Tress)在不同病程阶段多发性骨髓瘤(multiple myeloma,MM)患者外周血中的变化和临床意义,初步探讨MM患者的免疫抑制机制.方法 流式细胞术检测56例MM患者及30例健康志愿者外周血CD4+ CD25+、CD4+ CD25high、CD4+ CD25+ CD127low、CD4+ CD25high CD127low T细胞的比例并分析比较.结果 1)56例MM患者:化疗后组CD4+ CD25+、CD4+ CD25high、CD4+ CD25+ CD127low、CD4+ CD25high CD127low T 细胞的比例均高于正常组,差异具有显著性;初诊组的CD4+ CD25+ CD127low T细胞与正常对照组比较没有差异,但CD4+CD25+、CD4+ CD25high、CD4+ CD25high CD127lwo T细胞与正常对照组比较差异具有显著性;初诊组CD4+ CD25+T细胞的比例与化疗后组相比没有差异,但其CD4+ CD25high 、CD4+ CD25+ CD127low、CD4+ CD25high CD127low T细胞的比例均低于化疗后组,差异具有统计学意义.2)37例化疗后MM患者:稳定期与活动期的CD4+ CD25+、CD4+CD25+CD127low T细胞相比没有差异,但稳定期的CD4+ CD25high、CD4+ CD25high CD127low T细胞明显低于活动期.结论 CD4+ CD25+ Tregs在MM患者外周血中比例明显升高,且化疗可能影响其在外周血的比例;活动期MM患者CD4+ CD25+ Tregs的比例明显高于稳定期.这些提示CD4+ CD25+ Tregs可能是MM免疫抑制的一个重要原因.     

八色流式细胞术检测人外周血BCG特异性效应型记忆CD4+T细胞的表型特征

目的:检测BCG刺激后,PPD+正常人外周血中细胞因子产生及其亚群.方法:分离PPD+正常人外周血单个核细胞(PBMC),BCG刺激后检测CD4+和CD8+T细胞细胞因子分泌,并用八色流式细胞术分析BCG特异性T细胞亚群.结果:BCG刺激PBMC后,主要是CD4+T细胞分泌Th1细胞因子(IFN-γ、IL-2和TNF-α),而CD8+T细胞几乎不产生细胞因子.进一步分析分泌细胞因子的细胞亚群,主要是CD4+CD45RO+ CD62L(-)CD27(-)和CD4+ CD45RO+ CD62L(-)CD27+分泌细胞因子.结论:BCG刺激PPD+正常人外周血PBMC后,主要诱导CD4+T细胞分泌细胞因子,且该细胞表现出CD4+CD45RO+ CD62L(-)效应型记忆细胞特征,可能在预防结核感染中发挥重要作用.     

A role for CD4+CD25+ T cells in regulation of the immune response during human tuberculosis

Active tuberculosis (TB) is associated with prolonged suppression of Mycobacterium tuberculosis (MTB)-specific immune responses, but mechanisms involved are understood incompletely. We investigated a potential role for CD4+CD25+ regulatory T cells in depressed anti-MTB immunity by evaluating serially CD4 cell phenotype and interferon (IFN)-gamma production by mononuclear cells from patients with TB. At diagnosis, frequencies of CD4+CD25+ T cells were increased in blood from TB patients compared to healthy purified protein derivative (PPD)-positive controls (with a history of prior TB exposure), and remained elevated at completion of therapy (6 months). By contrast, expression of another activation marker, CD69, by CD4 T cells was increased at diagnosis, but declined rapidly to control levels with treatment. Among CD4+CD25+ T cells from TB patients at diagnosis those expressing high levels of CD25, probably representing regulatory T cells, were increased 2.9-fold when compared to control subjects, while MTB-stimulated IFN-gamma levels in whole blood supernatants were depressed. A role for CD4+CD25+ T cells in depressed IFN-gamma production during TB was substantiated in depletion experiments, where CD25+-depleted CD4 T cells produced increased amounts of IFN-gamma upon MTB stimulation compared to unseparated T cells. At follow-up, IFN-gamma production improved most significantly in blood from TB patients with high baseline frequencies of CD4+CD25+ T cells (more than threefold higher than controls for both total and CD25hi+ CD4 T cells), who also had a significant drop in frequencies of both total and 'regulatory' CD4+CD25+ T cells in response to treatment. Expansion of CD4+CD25+ regulatory T cells during active TB may play a role in depressed T cell IFN-gamma production.     

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。     

Reverse signalling of membrane-integrated tumour necrosis factor differentially regulates alloresponses of CD4+ and CD8+ T cells against human microvascular endothelial cells

Reverse signalling of membrane-integrated ligands is a common phenomenon in the tumour necrosis factor (TNF) family and contributes to the pleiotropy of this pro-inflammatory cytokine and to the plasticity of the immune system in general. Transmembrane TNF (mTNF) itself can induce resistance to bacterial endotoxin in monocytes and can stimulate the immune activity of mitogen-activated, as well as of virus-infected, T cells. The aim of the present study was to investigate the influence of reverse signalling of mTNF on the allogeneic activity of CD4+ and CD8+ T cells against human microvascular endothelial cells (HMEC), as targets of various inflammatory responses. The proliferative potential of CD4+ T cells towards HMEC was attenuated by mTNF signalling, whereas stimulation of mTNF on CD8+ T cells increased their cytotoxic potential against HMEC. These effects were specific for reverse signalling of mTNF, as a blockade of the classical TNF-TNF receptor interaction by a neutralizing TNF receptor antibody had no effect. Cytokine profiling of the effector cells revealed that the anti-endothelial CD4+ T cells were of a T helper 2 (Th2) phenotype, whereas CD8+ T cells mainly produced cytotox. T cell 1 (Tc1) cytokines. From the results obtained in this study, we conclude that reverse signalling of mTNF differentially modulates CD4+ and CD8+ T-cell activity against allogeneic endothelial cells, which should be taken into account in settings of therapeutic cytokine antagonisms.     

ConA刺激对CD4~+CD25~+调节性T细胞趋化特性及其表面趋化因子受体CCR4/CCR6表达的影响

目的体外动态观察ConA激活的调节性T细胞表面趋化因子受体的表达变化及其趋化特性,为利用调节性T细胞诱导免疫耐受提供线索。方法常规分离正常健康人外周血单个核细胞,免疫磁珠阴性分选CD4+T细胞;加FITC-An-tiCD4抗体,APC-AntiCD25抗体,PE-AntiCD127抗体上流式细胞仪分选出CD4hiCD127loCD25hi-int细胞。纯化的调节性T细胞与CD4+CD25-T分别用ConA(10μg/mL)刺激0、24、48h后,用趋化因子CCL1、CCL5、CCL20、CCL22做趋化实验,观察各趋化因子作用下调节性T细胞与CD4+CD25-T细胞的趋化特性。同时,流式细胞仪检测CCR4与CCR6的表达。结果分离得到的调节性T细胞纯度为97.4%,活细胞率为95%,得率:4.1%。CCL1、CCL20、CCL22均可趋化调节性T细胞,且在ConA激活后趋化效率随时间而改变。CCL1与CCL22对调节性T细胞的趋化指数显著高于CD4+CD25-T细胞;CCL20对调节性T细胞和CD4+CD25-T细胞趋化指数都很高;CCL5对调节性T细胞趋化性则显著弱于CD4+CD25-T细胞。ConA刺激后...     

Mycobacterium tuberculosis‐specific CD4+ T‐cell response is increased,and Treg cells decreased,in anthelmintic‐treated patients with latent TB

In many settings, adults with active or latent tuberculosis will also be coinfected with helminths. Our study aimed to investigate how anthelmintic treatment modulates antimycobacterial immunity, in a setting where helminth reinfection should not occur. We investigated the potential impact of helminth infection on immune responses to Mycobacterium tuberculosis (Mtb) in patients with latent Mtb infection with or without helminth infection (Strongyloides or Schistosoma), and tested T‐cell responses before and after anthelmintic treatment. The study was performed in migrants resident in the United Kingdom, where reexposure and reinfection following anthelmintic treatment would not occur. The frequency of CD4⁺IFN‐γ⁺ T cells was measured following stimulation with Mtb Purified Protein Derivative or ESAT‐6/CFP‐10 antigen, and concentrations of IFN‐γ in culture supernatants measured by ELISA and multiplex bead array. Helminth infection was associated with a lower frequency of CD4⁺IFN‐γ⁺ T cells, which increased following treatment. Patients with helminth infection showed a significant increase in CD4⁺FoxP3⁺ T cells (Treg) compared to those without helminth infection. There was a decrease in the frequency of Treg cells, and an associated increase in CD4⁺IFN‐γ⁺ T cells after the anthelmintic treatment. Here, we show a potential role of Treg cells in reducing the frequency and function of antimycobacterial CD4⁺IFN‐γ⁺ T cells, and that these effects are reversed after anthelmintic treatment.     

子宫内膜异位症患者外周血CD4~+CD25~+Foxp3~+调节性T细胞的变化

观察子宫内膜异位症患者外周血单个核细胞CD4~+CD25~+Foxp3~+调节性T细胞的数量变化,初步探讨其意义。采用流式细胞术检测20例健康对照者(对照组)及46例子宫内膜异位症患者(疾病组临床r-AFS分期:Ⅰ～Ⅱ期26例,Ⅲ～Ⅳ期20例)外周血单个核细胞(PBMC)中CD4~+CD25~+Foxp3~+调节性T细胞数目,并计算CD4~+CD25~+Foxp3~+调节性T细胞占CD4~+T淋巴细胞的百分率;分析不同分期子宫内膜异位症患者外周血CD4~+CD25~+Foxp3~+调节性T细胞的变化。结果显示,与健康对照组相比,疾病组PBMC中CD4~+CD25~+Foxp3~+Treg占CD4~+T淋巴细胞的百分率及CD4~+CD25~+Foxp3~+Treg绝对数均明显升高(P<0.01,P<0.05);疾病组中,Ⅲ～Ⅳ期的PBMC中CD4~+CD25~+Foxp3~+Treg占CD4~+T淋巴细胞的百分比及CD4~+CD25~+Foxp3~+Treg绝对值较Ⅰ～Ⅱ期均明显升高(P<0.01,P<0.05)。提示子宫内膜异位症患者外周血CD4~+CD25~+Foxp3~+调节性T细胞数目和比例增多,可能存在自身免疫调节功能的紊乱,且与病程发展紧密相关。     

活动性肺结核病人外周血CD4~+/CD8~+Tim-3~+ T细胞群内记忆细胞分布特点

目的研究活动性肺结核病人外周血CD4+/CD8+Tim-3+T细胞群内记忆细胞分布特点。方法分离22例初治活动性肺结核病人PBMCs,用流式细胞仪分析比较CD4+/CD8+Tim-3+/Tim-3-T细胞群内的中央型记忆细胞(Tcm)和效应型记忆细胞(Tem)的分布。结果活动期初治肺结核病人外周血CD4+Tim-3+T细胞群包含更少的中央型记忆细胞(P<0.0001)和较多的效应型记忆细胞(P=0.0139),CD8+Tim-3+T细胞群包含较少的效应型记忆细胞(P=0.0065)。结论活动期初治肺结核CD4+Tim-3+T细胞群内含有更多的效应型记忆细胞可能会促使Tem对抗原的快速保护性免疫应答效应下降,从而促进结核分枝杆菌潜伏感染向活动性病变转变。Tim-3对记忆性T细胞分化、形成及功能的影响尚需进一步研究。     

Circulating CD137+CD8+ T cells accumulate along with increased functional regulatory T cells and thoracic tumour burden in lung cancer patients

CD137 is a promising target for immunostimulation strategies against cancer. Previous studies showed that CD137⁺CD8⁺ T cells are enriched in antitumour effector T cells in both preclinical tumour models and cancer patients, but to date, such T cells in the blood of lung cancer patients have not been sufficiently investigated. In this study, circulating antigen‐activated CD8⁺ T cell subsets, identified as CD137⁺CD8⁺ or PD‐1⁺ (programmed cell death protein 1) CD8⁺, and regulatory T cells (Treg), identified as CD4⁺CD25⁺CD127^low/?, in 40 untreated lung cancer patients and in 49 age‐ and sex‐matched healthy controls (HCs) were assessed by flow cytometry. Results were evaluated for associations with lung cancer patient clinical characteristics. Correlations between antigen‐activated CD8⁺ T cells and effector Treg (CTLA‐4⁺ [cytotoxic T‐lymphocyte antigen 4] CD4⁺CD25⁺CD127^low/?) were also investigated. Higher percentages of PD‐1⁺, CD137⁺ and PD‐1⁺CD137⁺ amongst CD8⁺ T cells were observed in lung cancer patients compared with HCs. The percentages of CD137⁺CD8⁺ and PD‐1⁺CD137⁺CD8⁺ T cell subsets amongst CD8⁺ T cells were positively correlated with thoracic tumour burden and were strongly positively correlated with the percentage of effector Treg subset. Smoking patients harboured higher percentages of the PD‐1⁺CD8⁺ T cell subset compared with non‐smoking patients. This study demonstrated that circulating antigen‐activated CD8⁺ T cells accumulated in lung cancer patients along with increased effector Treg and thoracic tumour burden. These findings aid a better understanding of immune‐host interactions in lung cancer patients using peripheral blood, and further support immunotherapeutic intervention strategies using combination therapy for differential control of Treg and activation of tumour‐specific effector T cells.     

TLR2 engagement on CD4+ T cells enhances effector functions and protective responses to Mycobacterium tuberculosis

We have previously demonstrated that mycobacterial lipoproteins engage TLR2 on human CD4⁺ T cells and upregulate TCR‐triggered IFN‐γ secretion and cell proliferation in vitro. Here we examined the role of CD4⁺ T‐cell‐expressed TLR2 in Mycobacterium tuberculosis (MTB) Ag‐specific T‐cell priming and in protection against MTB infection in vivo. Like their human counterparts, mouse CD4⁺ T cells express TLR2 and respond to TLR2 costimulation in vitro. This Th1‐like response was observed in the context of both polyclonal and Ag‐specific TCR stimulation. To evaluate the role of T‐cell TLR2 in priming of CD4⁺ T cells in vivo, naive MTB Ag85B‐specific TCR transgenic CD4⁺ T cells (P25 TCR‐Tg) were adoptively transferred into Tlr2^?/? recipient C57BL/6 mice that were then immunized with Ag85B and with or without TLR2 ligand Pam₃Cys‐SKKKK. TLR2 engagement during priming resulted in increased numbers of IFN‐γ‐secreting P25 TCR‐Tg T cells 1 week after immunization. P25 TCR‐Tg T cells stimulated in vitro via TCR and TLR2 conferred more protection than T cells stimulated via TCR alone when adoptively transferred before MTB infection. Our findings indicate that TLR2 engagement on CD4⁺ T cells increases MTB Ag‐specific responses and may contribute to protection against MTB infection.     

Anti‐tumour necrosis factor treatment increases circulating T helper type 17 cells similarly in different types of inflammatory arthritis

We investigated changes in circulating T helper type 17 (Th17) cells following anti‐tumour necrosis factor (TNF) in rheumatoid arthritis (RA), ankylosing spondylitis (AS) and psoriatic arthritis (PsA) patients. Peripheral blood mononuclear cells (PBMC) were isolated from 25 RA, 15 AS and eight PsA patients at baseline 4 and 12 weeks after treatment, and Th17 cell frequencies were analysed using interleukin (IL)‐17 enzyme‐linked immunospot (ELISPOT) and flow cytometry. A significant increase in IL‐17‐producing cells was observed by ELISPOT in RA and AS patients at 12 weeks. Flow cytometry confirmed significant increases in CD4⁺IL‐17⁺ cells at 12 weeks in RA and AS and 4 weeks in PsA patients. Anti‐TNF treatment increases circulating Th17 cells in three different diseases.     

Progranulin promotes tumour necrosis factor‐induced proliferation of suppressive mouse CD4+ Foxp3+ regulatory T cells

Progranulin (PGRN) is a pleiotropic growth factor with immunosuppressive properties. Recently, it was reported that PGRN was an antagonist of tumour necrosis factor (TNF) receptors, preferentially for TNFR2. However, we and others showed that TNF–TNFR2 interaction was critical for the activation and expansion of functional CD4⁺ Foxp3⁺ regulatory T (Treg) cells. We therefore examined the effect of PGRN on the proliferation of naturally occurring murine suppressive Treg cells induced by TNF. Consistent with our previous reports, TNF overcame the hyporesponsiveness of highly purified Treg cells to T‐cell receptor stimulation. Furthermore, in the presence of interleukin‐2, TNF preferentially stimulated proliferation of Treg cells contained in unfractionated CD4 cells. These effects of TNF on suppressive Treg cells were markedly increased by exogenous PGRN. TNF and TNFR2 interactions are required for this effect of PGRN, because the PGRN by itself did not stimulate Treg cell proliferation. The effect of PGRN on Treg cells was abrogated by antibody against TNFR2, and Treg cells deficient in TNFR2 also failed to respond to PGRN. Furthermore, PGRN also enhanced the proliferative responses of effector T cells to TNF, but to a lesser extent than that of Treg cells, presumably caused by the different levels of TNFR2 expression on these two subsets of CD4 cells. Hence, our data clearly show that PGRN promotes, rather than inhibits, the functional consequence of TNF–TNFR2 interaction on Treg cells.     

CD4+ T cell-independent maintenance and expansion of memory CD8+ T cells derived from in vitro dendritic cell activation

CD4+ T cells are essential for the maintenance of CD8+ memory T (Tm) cells following acute infection, but the importance of CD4+ T cells for the maintenance and expansion of CD8+ Tm cells to non-infectious antigens remains mostly unknown. Here, we showed that ovalbumin (OVA)-specific CD8+ Tm cell precursors derived from in vitro stimulation of TCR transgenic OT I CD8+ T cells with OVA protein-pulsed bone marrow-derived dendritic cells (DCOVA) can give rise to functional CD8+ Tm cells after adoptively transferred into mice. These CD8+ Tm cells can be maintained and remain fully functional in CD4+ T cell-absent environments in vivo. Furthermore, CD4+ T cells are not essential for the expansion of these CD8+ Tm cells. Finally, these in vitro DCOVA-activated CD8+ Tm cells maintained in CD4-deficient mice are also able to confer fully protective immunity against a later challenge of OVA-expressing tumor cells. Collectively, these findings demonstrate that in contrast to acute infections, maintenance and expansion of CD8+ Tm cells after priming with OVA protein-pulsed dendritic cells are independent of CD4+ T cells.     

T helper 1 (Th1)/Th2 cytokine expression shift of peripheral blood CD4+ and CD8+ T cells in patients at the post-acute phase of stroke

Local humoral and cellular immune responses modulate the inflammatory processes involved in the development of atherosclerotic lesions, as well as in the evolution of brain infarcts in stroke patients. The role of systemic adaptive immunity on the progression of such disease manifestations is less clear. In the current study, we evaluated the percentages of T helper 1 (Th1) [interleukin (IL)-2, interferon (IFN)-gamma] and Th2 (IL-4, IL-10) cytokine-producing peripheral blood CD4+ and CD8+ T cells in 23 patients with a history of ischaemic stroke (IS) at the chronic stable phase of the disease (median post-stroke time 34.5 months). Seven stroke-free individuals matched for age and vascular risk factors (matched controls, MC) were collected for comparison. To measure cytokine values at baseline and after stimulation, we used a flow cytometry method of intracellular cytokine staining. Intrinsic Th1 and Th2 cytokine production in unstimulated T cells was negligible in all study participants. Following mitogenic stimulation with phorbol 12-myristate13-acetate/ionomycin, both the IS and the MC groups exhibited a similarly strong Th1 response; IL-2 production predominated in the CD4+ T cells and IFN-gamma in the CD8+ T cells. However, when measuring the Th2 cytokine-production capacity post-stimulation, a significant increase in the percentage of IL-4-producing T cells was observed in the IS groups, compared with the MC group, resulting in a significantly lower ratio of IFN-gamma-/IL-4-producing T cells. No such Th2 enhancement could be confirmed for the case of IL-10. We propose that in IS patients there is a systemic shift of the immune system towards Th2 responses at the late post-acute phase of stroke.