Lack of evidence for the Th2 predominance in patients with chronic hepatitis C

A T helper (Th)1 to Th2 shift has been proposed to be a critical pathogenic determinant in chronic hepatitis C. Here, we evaluated mitogen-induced and hepatitis C virus (HCV) core antigen-induced cytokine production in 28 patients with biopsy-proven chronic hepatitis C. Flow cytometry demonstrated that after mitogenic stimulation the percentage of Th2 cells (IL-4 + or IL-13 +) and Th0 cells (IFN-gamma/IL-4 + or IL-2/IL-13 +) did not differ between patients and controls. In contrast, the percentage of Th1 cells (IFN-gamma + or IL-2 +) was significantly increased in CD4 +, CD8 +, 'naive'-CD45RA + and 'memory'-CD45RO + T-cell subsets from patients versus controls. Similar results were obtained by ELISA testing supernatants from mitogen-stimulated, unfractionated peripheral blood mononuclear cell (PBMC) cultures. Interferon-alpha treatment was associated with a reduction in the mitogen-induced Th1 cytokine response in those patients who cleared their plasma HCV-RNA. Analysis of cytokine expression by CD4 + T cells after HCV core antigen stimulation in a subgroup of 13 chronic hepatitis C patients demonstrated no cytokine response in 74% of these patients and an IFN-gamma-restricted response in 26%. Finally, no Th2 shift was found in lipopolysaccharide-stimulated monocytes. These data indicate that a Th1 to Th2 shift does not occur in chronic hepatitis C.     

Cytokine patterns correlate with liver damage in patients with chronic hepatitis B and C

T-cell immunoregulatory cytokines influence the persistence of hepatitis C virus (HCV) chronic infection and the extent of liver damage. Th1 cytokines positively correlate with hepatic inflammation in chronic hepatitis B virus (HBV) infection. The pro-inflammatory, cytokines IL-6 and IL-18, are involved in viral clearance and in metabolic and viral hepatic diseases, respectively. The aim of this study was to evaluate the profile of Th1/Th2 cytokines in HCV and HBV hepatitis. HBV-infected patients showed higher plasma IFN-gamma levels than the HCV+ patients or the control group (p <0.0001). Plasma TNF-alpha and IL-2 were higher in HBV+ in comparison to HCV+ patients (p <0.001) or the control group (p <0.005). Plasma IL-6 and IL-18 were higher in both groups of patients compared to the control group (p <0.04). In HCV+ and HBV+ groups, IL-6 was positively correlated with the duration of the illness (p <0.01 and <0.001, respectively) and viral load (p <0.001 and <0.001, respectively), while IL-18 was positively correlated with serum ALT activity (p <0.01 and <0.001, respectively) and serum AST activity (p <0.01 and <0.001, respectively). We found that in HCV+ and HBV+ patients there are higher levels of Th1 cytokines, particularly in the course of chronic hepatitis B, and that IL-18 and IL-6 levels may have important roles as markers of both inflammation and hepatic injury, particularly in the course of hepatitis C.     

HBcAg-specific cytokine production by CD4 T lymphocytes of children with acute and chronic hepatitis B

In the presented studies HBcAg-specific cytokine production (IFN-gamma, IL-2, IL-4, IL-5 and IL-10) was evaluated, by Th lymphocytes isolated from peripheral blood of children with acute or chronic B hepatitis. Moreover, effect of IL-10 neutralization was examined on HBcAg-induced secretory response of Th lymphocytes obtained from children with chronic B hepatitis. The studies were performed on 12 children with acute self-limited B hepatitis and 20 children with chronic active B hepatitis. CD4 T cells were isolated from peripheral blood of the patients, cultured for 48h in presence of rHBcAg or in its absence (control). Production of studied cytokines was monitored using ELISPOT and ELISE assays. The course of acute self-limited B hepatitis was associated with preferential Th1-type response, manifested by elevated production of IFN-gamma and IL-2. On the other hand, in chronic B hepatitis a diminished response to HBcAg of both Th1 and Th2 types was disclosed, characterized by very low secretion of IFN-gamma, IL-2, IL-4 and IL-5. In parallel, preferential antigen-specific production of IL-10 was noted and its suppressive effect on HBcAg-induced response of Th1 cells. The results permitted to conclude that in children with acute self-limited B hepatitis preferential HBcAg-specific activation of Th1 lymphocytes may be of significance for efficient anti-HBV immune response. On the other hand, development of chronic B infection in children seems to be determined by disturbed HBcAg-specific functions of both Th1 and Th2 cells whereas activity of the disease may be controlled by anti-inflammatory response of antigen-presenting cells and/or of regulatory CD4 T lymphocytes, involving IL-10 production.     

Transient inhibition of Th1-type cytokine production by CD4 T cells in hepatitis B core antigen immunized mice is mediated by regulatory T cells

The non-cytopathic hepatitis B virus (HBV) can induce chronic infections characterized by weak and limited T cell responses against the virus. The factors contributing to the failure to clear HBV and subsequent development of chronic HBV infections are not clearly understood, but a strong interferon-gamma (IFN-gamma) response by CD4+ T cells against the nucleocapsid hepatitis B core antigen (HBcAg) of the virus appears to be important for viral clearance. The present study documents depressed numbers of CD4+ T cells secreting IFN-gamma and interleukin-2 (IL-2) in enzyme-linked immunospot assay (ELISPOT) assays restimulated for 24 hr with antigen following both primary and secondary immunizations of mice with recombinant hepatitis B core antigen (rHBcAg). The kinetics of these responses showed that the depression occurred following a peak response and lasted approximately 2 weeks before returning to the previous peak levels. The depression was abrogated by depletion of CD25+ cells prior to culture in the ELISPOT assay, suggesting inhibition by regulatory T cells. This inhibition of IFN-gamma and IL-2 production was also reversed by in vitro restimulation of the test cells for 48 hr rather than 24 hr in the assay. No such transient, reversible inhibition was detected in the production of IL-5, a Th2-type cytokine. The inhibition in cytokine production did not appear to correlate with the number of antibody-secreting cells or the isotypes produced. This delay by regulatory T cells of Th1-type cytokine production could contribute to viral persistence in chronic HBV infection by interfering with the critical role IFN-gamma plays in protection against viral infections.     

Th1／Th2在慢性乙型、丙型肝炎中的作用

病毒性肝炎的发病及转归与细胞免疫机制有很密切的关系。辅助性T细胞（Th）是体内一类重要的调节细胞,根据其产生细胞因子的不同分为Th1和Th2亚型,分别参与调节细胞免疫和体液免疫。Th1和Th2细胞在病毒性肝炎中发挥重要作用,Th1／Th2失衡引起病毒性肝炎慢性化。采用单种细胞因子纠正Th1／Th2失衡方法在慢性乙型、丙型肝炎临床治疗中的研究进展,为治疗慢性病毒性肝炎提供了新思路。     

Different cytokine profiles of peripheral blood mononuclear cells from patients with persistent and self-limited hepatitis C virus infection

An imbalance between T helper cell Th1 and Th2 like cytokines has been described in several chronic infectious diseases. In an attempt to characterise the mechanism responsible for viral persistence in hepatitis C virus (HCV)-related chronic infection, we analyzed Th1 cytokines (IL-2, IL-12, IFN-gamma) and Th2 cytokines (IL-4, IL-10) production by phytohemagglutinin (PHA)-stimulated peripheral blood mononuclear cells (PBMC) derived from ten patients with viremic chronic hepatitis C, five healthy HCV seropositive individuals and four HCV seronegative individuals. Cytokine production was determined by enzyme-linked immunosorbent assay (ELISA) after 72 h of stimulation. The results showed that the production of IFN-gamma by PHA-stimulated PBMC was decreased in patients with hepatitis C infection (P=0.05). IL-4 production was not detected in both patients and controls, while no difference was observed for IL-2, IL-10 and IL-12 production between patients and controls. Furthermore, IL-12 and IFN-gamma production was weaker in patients with viremic chronic hepatitis C than in subjects who were able to clear the virus (P=0.01; P=0.03, respectively). These results clearly indicate that a defect both in IL-12 and IFN-gamma production may contribute to the persistence of HCV infection.     

Sequential production of Th1 and Th2 cytokines in response to live bacillus Calmette-Guérin.

Causes of individual variation in susceptibility to mycobacterial diseases are only partly understood. An efficient cell-mediated immune response is crucial for resistance. Macrophages and T cells interact to eliminate the mycobacteria, partially through the effects of secreted cytokines. A vigorous anti-bacterial inflammatory response is sometimes accompanied by severe tissue damage, while immunosuppression leads to progressive infection. Here, live, attenuated Mycobacterium bovis, bacillus Calmette-Guérin (BCG), was used as a model antigen to study cytokine production at the single-cell level in response to mycobacteria. Peripheral blood mononuclear cells from healthy individuals were challenged in vitro and the kinetics and frequencies of cytokine-producing cells were studied by immunofluorescent visualization of intracellular cytokines. Fourteen cytokines were assayed; interleukin-1 alpha (IL-1 alpha), IL-1 beta, IL-1 receptor antagonist (IL-1ra), IL-2, IL-3, IL-4, IL-5, IL-6, IL-8, IL-10, interferon-gamma (IFN-gamma), tumour necrosis factor-alpha (TNF-alpha), TNF-beta and granulocyte-macrophage colony-stimulating factor (GM-CSF). A sequential production of T helper-1 (Th1) and T helper-2 (Th2) cytokines was induced by BCG. Early, at days 1-2 after stimulation, the response was dominated by monokines and a low IFN-gamma and TNF-beta production. At days 4-5 there was a marked production of Th1 lymphokines, with approximately 6% IFN-gamma+ cells, 4% TNF-beta+ cells and 2% IL-2+ cells. Late in the reaction, at days 10-12, a Th2 response with IL-4, IL-5 and IL-10 was detected, while the synthesis of Th1 lymphokines and monokines declined. Overall, our results provide further evidence of IFN-gamma as the major cytokine induced by mycobacteria in healthy individuals, but also suggest that Th2 cytokines participate in the response.     

血清Th1/Th2细胞因子水平与慢性丙型肝炎临床及干扰素疗效关系的研究

目的 探讨血清Th1和Th2细胞因子水平与慢性丙型肝炎患者病情进展及干扰素疗效的关系.方法 血清细胞因子检测应用ELISA法,HCV基因分型应用直接测序法,HCVRNA载量采用荧光定量PCR法.结果 慢性丙型肝炎患者血清IL-2和TGF-β含量明显低于健康对照组,IL-5含量明显高于后者;血清IL-6含量与ALT水平呈正相关,与RNA载量呈负相关;HCV基因型1型患者IL-6含量明显高于2型,2a型IL-2含量低于2b型;随着感染时间的延长,血清IL-2呈下降趋势,IL-6呈升高趋势,而TGF-β则先升高之后逐渐下降.干扰素治疗应答组和无应答组治疗前血清细胞因子水平均差异无统计学意义,但应答组治疗结束时IFN-γ含量较治疗前明显升高.结论 慢性丙型肝炎患者存在Th1/Th2细胞因子失衡并与临床表现相关;治疗前血清Th1/Th2细胞因子水平不能对疗效进行预测,干扰素诱导的Th1细胞优势反应与持续应答有关.     

Human T helper (Th) cell lineage commitment is not directly linked to the secretion of IFN-gamma or IL-4: characterization of Th cells isolated by FACS based on IFN-gamma and IL-4 secretion

Upon activation in vitro, only a fraction of the bulk human T helper cell cultures secret the hallmark Th1/2 cytokines (IFN-gamma for Th1 and IL-4 for Th2, respectively). It is uncertain whether these IFN-gamma-/IL-4- cells are differentiated Th1 or Th2 cells. Here, we have characterized live IFN-gamma+, IL-4+ and IFN-gamma-/IL-4- cells isolated from Th cell cultures treated under Th1 or Th2 polarizing conditions by employing affinity matrix capture technology. RNA samples from the sorted cells were analyzed by real time RT-PCR and microarrays. The double negative cells from either Th1 or Th2 cultures expressed lower levels of Th1/Th2 marker cytokine genes (IFNgamma, IL4, and IL5). However, they were comparable with the IFN-gamma+ or IL-4+ cells in the expression levels of other Th1/Th2 marker genes (GATA3, Tbet, and IL12Rbeta2). Most importantly, these double negative cells were already committed in their Th1/Th2 lineages. Gene expression profiling analysis showed that very few previously identified Th1/Th2 marker genes were differentially expressed between the IFN-gamma or IL-4 producers and the non-producers, further underscoring the similarity between these two groups.     

Th1、Th2在慢乙肝重叠戊肝感染导致重症化中的作用

目的研究慢性乙型肝炎重叠戊肝感染的临床及免疫指标的变化特点与临床转归。方法选择慢性乙肝重叠戊型肝炎患者及同期单纯慢性乙肝患者各30例,分为重叠感染组和对照组,采用ELISA法检测戊型肝炎病毒以及乙肝病毒e系统状态,PCR法检测HBV—DNA,对慢性乙型肝炎重叠戊肝感染患者进行肝功能、免疫指标IL-4、TNF—α、IFN-γ、Th1／Th2的检测,并与单纯慢性乙型肝炎进行对照分析,观察两组在治疗8周时的肝功能恢复情况。结果重叠感染戊肝患者发生重症肝炎的人数多（9例vs6例,P〈0．05）,e抗原转阴比例高（2例vs1例）,ALT、TBIL恢复较差,免疫指标提示与对照组相比,重叠感染组IL-4水平降低（P〈0．05）、TNF-α、IFN-γ变化不大（P〉0．05）,Th1／Th2水平明显增高（P〈0．05）。结论慢性乙型肝炎重叠HEV感染后病情趋向重症化,可能是由于抗炎性细胞因子IL-4表达减少,细胞免疫增强导致肝细胞大量损害所致。     

Heterogeneity in cytokine profiles of Babesia bovis-specific bovine CD4+ T cells clones activated in vitro.

The central role of T cells in the immune response against hemoprotozoan parasites, both as helper cells for T cell-dependent antibody production and as effector cells acting on intracellular parasites through the elaboration of cytokines, has prompted an investigation of the bovine cellular immune response against Babesia bovis antigens. CD4+ T helper (Th) cell clones generated from four B. bovis-immune cattle by in vitro stimulation with a soluble or membrane-associated merozoite antigen were characterized for reactivity against various forms of antigen and against different geographical isolates of B. bovis and B. bigemina and analyzed for cytokine production following mitogenic stimulation with concanavalin A. Biological assays to measure interleukin-2 (IL-2), IL-4, gamma interferon (IFN-gamma), and tumor necrosis factor alpha or tumor necrosis factor beta and Northern (RNA) blot analysis to verify the expression of IL-2, IL-4, IFN-gamma, and tumor necrosis factor alpha revealed differential production of cytokines by the Th cell clones. The majority of clones expressed the Th0 pattern of cytokines: IFN-gamma, IL-4, and IL-2. One clone expressed the Th1 profile (IFN-gamma and IL-2 but not IL-4), whereas none of the clones expressed the Th2 profile. All of the Th cell clones examined expressed the low-molecular-weight isoform of the leukocyte common antigen associated with a memory cell phenotype (CD45RO), and all expressed the lymph node homing receptor (L-selectin). These results extend our previous finding of differential cytokine expression by B. bovis-specific Th cell clones and confirm the identity of the specific cytokines produced, showing that a Th0 response is preferentially induced in a panel of 20 CD4+ T cell clones obtained from immune cattle.     

Reduced Th1, but not Th2, cytokine production by lymphocytes after in vivo exposure of healthy subjects to endotoxin

Endotoxin (lipopolysaccharide [LPS]) tolerance is characterized by a reduced capacity of monocytes to produce proinflammatory cytokines upon restimulation in vitro. To determine whether LPS exposure induces a change in lymphocyte cytokine production and whether this results in a shift in the T-helper 1 (Th1)/Th2 balance, whole blood obtained from seven healthy subjects before and after an intravenous injection of LPS (4 ng/kg) was stimulated in vitro with the T-cell stimulus anti-CD3/CD28 or staphylococcal enterotoxin B. Whole-blood production of the Th1 cytokines gamma interferon (IFN-gamma) and interleukin-2 (IL-2) was markedly reduced at 3 and 6 h, while the production of the Th2 cytokines IL-4 and IL-5 was not influenced or was slightly increased. The IFN-gamma/IL-4 ratio was strongly decreased at 6 h. Serum obtained after LPS exposure could slightly inhibit the release of IFN-gamma but increased IL-4 production during stimulation of blood drawn from subjects not previously exposed to LPS. Normal serum also inhibited IFN-gamma production, albeit to a lesser extent. LPS exposure influences lymphocyte cytokine production, resulting in a shift toward a Th2 cytokine response, an effect that may be mediated in part by soluble factors present in serum after LPS administration in vivo.     

Increased Th1 and Th2 allergen-induced cytokine responses in children with atopic disease

BACKGROUND: Polyclonal cytokine responses following stimulation of T cells with mitogens or superantigens provides information on cytokine production from a wide range of T cells. Alternatively allergen-induced T cell responses can provide information on cytokine production by allergen-reactive T cells. While there is evidence of increased Th2 and reduced Th1 cytokine production following T cell stimulation with non-specific mitogens and superantigens, the evidence that Th1 cytokine production to allergens is decreased in line with a postulated imbalance in Th1/Th2 responses is unclear, with studies finding decreased, no difference or increased IFN-gamma responses to allergens in atopic subjects. OBJECTIVE: To examine childhood polyclonal and allergen-induced cytokine responses in parallel to evaluate cytokine imbalances in childhood atopic disease. METHODS: PBMC cytokine responses were examined in response to a polyclonal stimulus, staphylococcal superantigen (SEB), in parallel with two inhalant allergens, house dust mite (HDM) and rye grass pollen (RYE), and an ingested allergen, ovalbumin (OVA), in (a) 35 healthy children (non-atopic) and (b) 36 children with atopic disease (asthma, eczema and/or rhinitis) (atopic). RESULTS: Atopic children had significantly reduced IFN-gamma and increased IL-4 and IL-5 but not IL13 production to SEB superantigen stimulation when compared with non-atopic children. HDM and RYE allergens stimulated significantly increased IFN-gamma, IL-5 and IL-13, while OVA stimulated significantly increased IFN-gamma production in atopic children. CONCLUSION: We show that a polyclonal stimulus induces a reduced Th1 (IFN-gamma) and increased Th2 (IL-4 and IL-5) cytokine pattern. In contrast, the allergen-induced cytokine responses in atopic children were associated with both increased Th1 (INF-gamma) and Th2 (IL-5 and IL-13) cytokine production. The increased Th1 response to allergen is likely to reflect prior sensitization and indicates that increases in both Th1 and Th2 cytokine production to allergens exists concomitantly with a decreased Th1 response to a polyclonal stimulus in atopic children.