Increased expression of plasma and cell surface co-stimulatory molecules CTLA-4, CD28 and CD86 in adult patients with allergic asthma

sCD163, sCD28, sCD80, and sCTLA-4 as soluble marker candidates for detecting immunosenescence

BACKGROUND

Inflammaging, the characteristics of immunosenescence, characterized by continuous chronic inflammation that could not be resolved. It is not only affect older people but can also occur in young individuals, especially those suffering from chronic inflammatory conditions such as autoimmune disease, malignancy, or chronic infection. This condition led to altered immune function and as consequent immune function is reduced. Detection of immunosenescence has been done by examining the immune risk profile (IRP), which uses flow cytometry. These tests are not always available in health facilities, especially in developing countries and require fresh whole blood samples. Therefore, it is necessary to find biomarkers that can be tested using stored serum to make it easier to refer to the examination. Here we proposed an insight for soluble biomarkers which represented immune cells activities and exhaustion, namely sCD163, sCD28, sCD80, and sCTLA-4. Those markers were reported to be elevated in chronic diseases that caused early aging and easily detected from serum samples using ELISA method, unlike IRP. Therefore, we conclude these soluble markers are beneficial to predict pathological condition of immunosenescence.

AIM

To identify soluble biomarkers that could replace IRP for detecting immunosenescence.

CONCLUSION

Soluble costimulatory molecule suchsCD163, sCD28, sCD80, and sCTLA-4 are potential biomarkers for detecting immunosenescence.

Current understanding of CTLA-4: from mechanism to autoimmune diseases

Autoimmune diseases (ADs) are characterized by the production of autoreactive lymphocytes, immune responses to self-antigens, and inflammation in related tissues and organs. Cytotoxic T-lymphocyte antigen 4 (CTLA-4) is majorly expressed in activated T cells and works as a critical regulator in the inflammatory response. In this review, we first describe the structure, expression, and how the signaling pathways of CTLA-4 participate in reducing effector T-cell activity and enhancing the immunomodulatory ability of regulatory T (Treg) cells to reduce immune response, maintain immune homeostasis, and maintain autoimmune silence. We then focused on the correlation between CTLA-4 and different ADs and how this molecule regulates the immune activity of the diseases and inhibits the onset, progression, and pathology of various ADs. Finally, we summarized the current progress of CTLA-4 as a therapeutic target for various ADs.

Immune checkpoint molecules in prevention and development of asthma

Allergic asthma is a respiratory disease initiated by type-2 immune responses characterized by secretion of alarmins, interleukin-4 (IL-4), IL-5, and IL-13, eosinophilic inflammation, and airway hyperresponsiveness (AHR). Immune checkpoints (ICPs) are inhibitory or stimulatory molecules expressed on different immune cells, tumor cells, or other cell types that regulate immune system activation and maintain immune homeostasis. Compelling evidence indicates a key role for ICPs in both the progression and prevention of asthma. There is also evidence of asthma development or exacerbation in some cancer patients receiving ICP therapy. The aim of this review is to provide an updated overview of ICPs and their roles in asthma pathogenesis, and to assess their implications as therapeutic targets in asthma.

Vps33B in Dendritic Cells Regulates House Dust Mite-Induced Allergic Lung Inflammation

Dendritic cells (DCs) are the most specialized APCs that play a critical role in driving Th2 differentiation, but the mechanism is not fully understood. Here we show that vacuolar protein sorting 33B (Vps33B) plays an important role in this process. Mice with Vps33b-specific deletion in DCs, but not in macrophages or T cells, were more susceptible to Th2-mediated allergic lung inflammation than wild-type mice. Deletion of Vps33B in DCs led to enhanced CD4⁺ T cell proliferation and Th2 differentiation. Moreover, Vps33B specifically restrained reactive oxygen species production in conventional DC1s to inhibit Th2 responses in vitro, whereas Vps33B in monocyte-derived DCs and conventional DC2s was dispensable for Th2 development in asthma pathogenesis. Taken together, our results identify Vps33B as an important molecule that mediates the cross-talk between DCs and CD4⁺ T cells to further regulate allergic asthma pathogenesis.

Bovine Holo-Beta-Lactoglobulin Cross-Protects Against Pollen Allergies in an Innate Manner in BALB/c Mice: Potential Model for the Farm Effect

The lipocalin beta-lactoglobulin (BLG) is a major protein compound in cow's milk, and we detected it in cattle stable dust. BLG may be a novel player in the farm protective effect against atopic sensitization and hayfever. In previous studies, we demonstrated that only the ligand-filled holo-form of BLG prevented sensitization to itself. Here, we investigated whether holo-BLG could, in an innate manner, also protect against allergic sensitization to unrelated birch pollen allergens using a murine model. BALB/c mice were nasally pretreated four times in biweekly intervals with holo-BLG containing quercetin-iron complexes as ligands, with empty apo-BLG, or were sham-treated. Subsequently, mice were intraperitoneally sensitized two times with apo-BLG or with the unrelated birch pollen allergen apo-Bet v 1, adjuvanted with aluminum hydroxide. After subsequent systemic challenge with BLG or Bet v 1, body temperature drop was monitored by anaphylaxis imaging. Specific antibodies in serum and cytokines of BLG- and Bet v 1-stimulated splenocytes were analyzed by ELISA. Additionally, human peripheral blood mononuclear cells of pollen allergic subjects were stimulated with apo- versus holo-BLG before assessment by FACS. Prophylactic treatment with the holo-BLG resulted in protection against allergic sensitization and clinical reactivity also to Bet v 1 in an unspecific manner. Pretreatment with holo-BLG resulted in significantly lower BLG-as well as Bet v 1-specific antibodies and impaired antigen-presentation with significantly lower numbers of CD11c+MHCII+ cells expressing CD86. Pretreatment with holo-BLG also reduced the release of Th2-associated cytokines from Splenocytes in BLG-sensitized mice. Similarly, in vitro stimulation of PBMCs from birch pollen allergic subjects with holo-BLG resulted in a relative decrease of CD3+CD4+ and CD4+CRTh2 cells, but not of CD4+CD25+CD127- Treg cells, compared to apo-BLG stimulation. In conclusion, prophylactic treatment with holo-BLG protected against allergy in an antigen-specific and -unspecific manner by decreasing antigen presentation, specific antibody production and abrogating a Th2-response. Holo-BLG therefore promotes immune resilience against pollen allergens in an innate manner and may thereby contribute to the farm protective effect against atopic sensitization.

A profile of TNFR2+ regulatory T cells and CD103+ dendritic cells in the peripheral blood of patients with asthma

The interaction of tolerogenic CD103⁺ dendritic cells (DCs) with regulatory T (Tregs) cells modulates immune responses by inducing immune tolerance. Hence, we determined the proportion of these cells in the peripheral blood mononuclear cells (PBMC) of asthmatic patients. We observed lower trends of CD11b^-CD103⁺ DCs and CD86 within CD11b^-CD103⁺ DCs, while increased levels of Foxp3 expressing CD25^+/-TNFR2⁺ cells in asthmatics. There was a positive correlation in the expression of Foxp3 within CD3⁺CD4⁺CD25⁺TNFR2⁺ Tregs and CD11b^-CD103⁺ as well as the expression of CD86 within HLA-DR⁺CD11c⁺CD11b^-CD103⁺ DCs. In conclusion, we suggest that the increased levels of Tregs in blood could continuously suppress the T helper 2 (Th2) cells activation in the circulation which is also supported by the increase of anti-inflammatory cytokines IL-10 and TNF. Overall, functional immunoregulation of the regulatory cells, particularly Tregs, exhibit immune suppression and induce immune tolerance linked with the immune activation by the antigen presenting cells (APC).

Silencing of CD86 in dendritic cells by small interfering RNA regulates cytokine production in T cells from patients with allergic rhinitis in vitro

The aim of the present study was to investigate the expression and role of the co‑stimulatory molecule T‑lymphocyte activation antigen CD86 (CD86) in dendritic cells (DCs) from the peripheral blood of patients with allergic rhinitis (AR) compared with those from healthy individuals. It was observed that mature DCs from the peripheral blood of patients with AR expressed high levels of the co‑stimulatory molecule CD86, but not CD80, compared with healthy control subjects. CD86 expression levels in DCs decreased significantly following transfection with siRNA in a lentiviral vector. Furthermore, the level of transforming growth factor‑β1 produced by T cells co‑cultured with DCs was significantly increased in the siRNA group, while interleukin (IL)‑4 and IL‑5 production was significantly decreased. The findings of the present study indicated that CD86 may play a pivotal role in the regulatory T cell/type 2 helper T cell imbalance in allergic inflammation.

Soluble immune checkpoint molecules: Serum markers for cancer diagnosis and prognosis

BACKGROUND

With the recent advances in the understanding of the interaction of the immune system with developing tumor, it has become imperative to consider the immunological parameters for both cancer diagnosis and disease prognosis. Additionally, in the era of emerging immunotherapeutic strategies in cancer, it is very important to follow the treatment outcome and also to predict the correct immunotherapeutic strategy in individual patients. There being enormous heterogeneity among tumors at different sites or between primary and metastatic tumors in the same individual, or interpatient heterogeneity, it is very important to study the tumor-immune interaction in the tumor microenvironment and beyond. Importantly, molecular tools and markers identified for such studies must be suitable for monitoring in a noninvasive manner.

RECENT FINDINGS

Recent studies have shown that the immune checkpoint molecules play a key role in the development and progression of tumors. In-depth studies of these molecules have led to the development of most of the cancer immunotherapeutic reagents that are currently either in clinical use or under different phases of clinical trials. Interestingly, many of these cell surface molecules undergo alternative splicing to produce soluble isoforms, which can be tracked in the serum of patients.

CONCLUSIONS

Several studies demonstrate that the serum levels of these soluble isoforms could be used as noninvasive markers for cancer diagnosis and disease prognosis or to predict patient response to specific therapeutic strategies.

Myeloid-Derived Suppressor Cells and Costimulatory Molecules in Children With Allergic Rhinitis

OBJECTIVES:

The aim of this study is to assess the level of myeloid-derived suppressor cells (MDSCs) and the expression of costimulatory molecules CD80 and CD86 on monocytes and their ligands (CD28) on T-lymphocytes in children with allergic rhinitis (AR).

METHODS:

The study included 60 children with AR and 50 controls. Flow cytometry was performed to analyze MDSCs and the expression of costimulatory molecules CD80 and CD86 on monocytes and their ligands (CD28) on T-lymphocytes.

RESULTS:

The percentages of total and monocytic MDSCs and the expression of costimulatory molecule CD86 on monocytes were significantly higher in children with AR than in healthy controls. In addition, the expressions of CD28 on CD4⁺ and CD8⁺ were significantly elevated in AR patients.

CONCLUSION:

The present study demonstrated that the percentages of MDSCs were significantly elevated in AR children. Moreover, the expressions of CD28 on CD4⁺ and CD8⁺ were significantly higher in children with AR.

Correlation between systemic inflammatory response and quality of life in patients with chronic rhinosinusitis

BACKGROUND

Local sinonasal inflammation resulting from altered T-cell immune signaling is a contributor to the pathogenesis of chronic rhinosinusitis (CRS). CRS patients experience negative impacts on quality of life (QOL) and suffer from comorbidities linked to systemic inflammation. However, systemic inflammatory profiling to evaluate the association between systemic inflammation and QOL in CRS has not been performed. Our objectives were to compare local and systemic inflammatory gene expression in patients with CRS to determine if systemic markers of inflammation associate with disease severity and disease-specific QOL.

METHODS

A prospective observational study was conducted comparing 16 patients with CRS to 10 controls. Inflammatory gene expression in the anterior ethmoid tissues and peripheral blood of patients was measured using multiplex gene expression analysis and correlated to disease severity (computed tomography and nasal endoscopy) and disease-specific QOL (22-item Sino-Nasal Outcome Test [SNOT-22] and Rhinosinusitis Disability Index) using linear regression analyses.

RESULTS

Patients with CRS showed significant increases in the expression of ctla4 and jak1 in sinonasal tissue and blood (p < 0.05), whereas the gene expression of hla-dqa1, hla-dqb1, and dusp4 was significantly decreased in patients with CRS compared to controls (p < 0.05). Soluble and local ctla4 and jak1 showed a significant positive correlation with clinical markers of disease severity and disease-specific QOL (p < 0.05).

CONCLUSION

Local and systemic gene expression involved in T-cell immune signaling was found to be significantly altered in the blood and sinonasal tissues of patients with CRS compared to controls and significantly correlated to disease severity and QOL in patients with CRS.

Fonctions de CD28, CTLA-4 et PD-1

FUNCTIONS OF CD28, CTLA-4 AND PD-1: 2018 is time in between since immunotherapies are recognized as treatments in cancer even in patients where they were supposed to be not or poorly active. We will focus on a review on facts meaning data reproduced during the last thirty-five years and what they have provided. We will focus on these data and question them regarding the novel and unexpected clinical that were not anticipated by the preclinical data. Consequently we will mainly present data regarding CD28, CTLA-4PD-1 and their ligands. We will not address the complex network of proteins involved in cosignalling in tissues.

Intranasal Treatment With 1, 25-Dihydroxyvitamin D3 Alleviates Allergic Rhinitis Symptoms in a Mouse Model

PURPOSE

Vitamin D is a potent immunomodulator. However, its role in the pathogenesis of allergic rhinitis is unclear.

METHODS

The aim of this study was to evaluate the antiallergic effect of intranasally applied vitamin D in an allergic rhinitis mouse model. BALB/c mice were intraperitoneally sensitized with ovalbumin (OVA) and alum before they were intranasally challenged with OVA. Then, they were intranasally administered 1, 25-dihydroxyvitamin D3 (0.02 μg) or solvent. Allergic symptom scores, eosinophil infiltration, cytokine mRNA levels (interleukin [IL]-4, IL-5, IL-10, IL-13 and interferon-γ) in the nasal tissue, and serum total immunoglobulin E (IgE) and OVA-specific IgE, IgG1, and IgG2a were analyzed and compared with negative and positive control groups. Cervical lymph nodes (LNs) were harvested for flow cytometry analysis and cell proliferation assay.

RESULTS

In the treatment group, allergic symptom scores, eosinophil infiltration, and mRNA levels of IL-4 and IL-13 were significantly lower in the nasal tissue than in the positive control group. The IL-5 mRNA level, serum total IgE, and OVA-specific IgE and IgG1 levels decreased in the treatment group; however, the difference was not significant. In the cervical LNs, CD86 expression had been down-regulated in CD11c⁺major histocompatibility complex II-high (MHCII^high) in the treatment group. Additionally, IL-4 secretion in the lymphocyte culture from cervical LNs significantly decreased.

CONCLUSIONS

The results confirm the antiallergic effect of intranasal 1,25-dihydroxyvitamin D3. It decreases CD 86 expression among CD11c⁺MHCII^high cells and T-helper type 2-mediated inflammation in the cervical LNs. Therefore, topically applied 1,25-dihydroxyvitamin D3 can be a future therapeutic agent for allergic rhinitis.

Fibrous nanocellulose, crystalline nanocellulose, carbon nanotubes, and crocidolite asbestos elicit disparate immune responses upon pharyngeal aspiration in mice

With the rapid development of synthetic alternatives to mineral fibers, their possible effects on the environment and human health have become recognized as important issues worldwide. This study investigated effects of four fibrous materials, i.e. nanofibrillar/nanocrystalline celluloses (NCF and CNC), single-walled carbon nanotubes (CNTs), and crocidolite asbestos (ASB), on pulmonary inflammation and immune responses found in the lungs, as well as the effects on spleen and peripheral blood immune cell subsets. BALB/c mice were given NCF, CNC, CNT, and ASB on Day 1 by oropharyngeal aspiration. At 14 days post-exposure, the animals were evaluated. Total cell number, mononuclear phagocytes, polymorphonuclear leukocytes, lymphocytes, and LDH levels were significantly increased in ASB and CNT-exposed mice. Expression of cytokines and chemokines in bronchoalveolar lavage (BAL) was quite different in mice exposed to four particle types, as well as expression of antigen presentation-related surface proteins on BAL cells. The results revealed that pulmonary exposure to fibrous materials led to discrete local immune cell polarization patterns with a T_H2-like response caused by ASB and T_H1-like immune reaction to NCF, while CNT and CNC caused non-classical or non-uniform responses. These alterations in immune response following pulmonary exposure should be taken into account when testing the applicability of new nanosized materials with fibrous morphology.

CD80 and CD86 knockdown in dendritic cells regulates Th1/Th2 cytokine production in asthmatic mice

Dendritic cells (DCs) are associated with the activation and differentiation of T helper (Th) cells. Cluster of differentiation (CD)80 and CD86, the co-stimulatory molecules highly expressed in DCs, have are prominent in promoting the differentiation of Th cells toward Th2 cells. However, little is known about the effect of CD80 and CD86 knockdown on Th1/Th2 cytokine production in mature DCs (mDCs). The aim of the present study was to investigate whether small-interfering RNA (siRNA) could suppress the surface expression of CD80 and CD86 in mDCs. The effects of CD80 and CD86 knockdown in mDCs on Th1/Th2 cytokine expression were examined using an asthmatic murine model. DCs were isolated, separated and cultured in vitro. Flow cytometry was used to examine the expression of CD11c, CD80 and CD86 on the DCs. The DCs were transfected with CD80- and CD86-specific siRNA, while non-siRNA and negative siRNA controls were also designed. Then, the mRNA and protein expression levels of CD80 and CD86 were determined by reverse transcription-quantitative polymerase chain reaction and flow cytometry, respectively. The levels of interferon (IFN)-γ and interleukin (IL)-4 produced by T cells co-cultured with mDCs were measured by enzyme-linked immunosorbent assay. Substantial downregulation of CD80 and CD86 mRNA and protein levels were observed in the mDCs following transfection with siRNA. The level of IFN-γ produced by T cells co-cultured with mDCs was significantly increased in the siRNA group, while IL-4 production was significantly decreased. These results show that specific targeting of CD80 and CD86 with siRNA is able to suppress CD80/CD86 expression and consequently regulate Th1/Th2 cytokine levels by increasing IFN-γ production and decreasing IL-4 levels in an asthmatic murine model.

Association between CTLA-4 exon-1 +49A/G polymorphism and asthma: an updated meta-analysis

The results of studies on association between CTLA-4 exon-1 +49A/G (rs231775) polymorphism and susceptibility to asthma are controversial. To derive a more precise estimation of the relationship between the CTLA-4 exon-1 +49A/G polymorphism and asthma, a meta-analysis of 15 published case-control studies was performed. 15 studies meeting our inclusion criteria comprising 4006 asthma cases and 3729 controls were included. The effect summary odds ratio (OR) and 95% confidence intervals were obtained. Publication bias was tested by funnel plot, Egger's test and heterogeneity was assessed. The combined results showed that there were significant differences in genotype distribution between asthma cases and control on the basis of all studies, GG + GA versus AA (OR = 0.76, 95% CI: 0.62-0.93; P = 0.008). When stratifying for the race, the phenomenon was found that asthma cases had a significantly higher frequency of GG/GA versus AA (OR = 0.71; 95% CI: 0.51-0.99; P = 0.04) than control in Caucasian. Stratifying subjects by age indicated an association between CTLA-4 +49 GG + GA genotype and asthma in children (OR = 0.75; 95% CI: 0.62-0.90; P = 0.002), but no association in adults (OR = 0.93; 95% CI: 0.76-1.14; P = 0.48). Furthermore, significant association was observed in atopic asthma under the fixed-effects model (GG + GA vs. AA: P = 0.03, OR = 0.81, 95% CI = 0.67-0.98, P heterogeneity = 0.22). Our meta-analysis results suggest that CTLA-4 exon-1 +49A/G polymorphism might be a risk factor for asthma susceptibility, at least in Caucasian, children, and patients with atopy status.

Enhancement of soluble CD28 levels in the serum of Graves' disease

Graves' disease is an autoimmune disease of the thyroid gland mediated by T cells. CD28, a member of costimulatory molecules, plays a pivotal role in regulating T-cell responses. Plasma-soluble CD28 is one form of CD28 in peripheral blood. To investigate the concentrations of soluble CD28 in patients with Graves' disease, we used a sensitive dual monoclonal antibody sandwich enzyme-linked immunosorbent assay (ELISA) to detect the soluble form of CD28. Our results suggested that mean concentrations of soluble CD28 in plasma of patients with Graves' disease were 1.79 ±1.52 ng/ml, and levels of soluble CD28 in healthy subjects were only 0.83 ±1.35 ng/ml. Concentrations of soluble CD28 detected in patients with Graves' disease were significantly higher than those of healthy subjects (p < 0.01). Moreover, there was a significant positive correlation between the concentrations of soluble CD28 in plasma and levels of FT3 (r = 0.663), FT4 (r = 0.624) and TRAb (r = 0.728) in serum, but a negative correlation was found between sCD28 levels and TSH (r = -0.726). Through in vitro experiments we observed that engagement of soluble CD28 protein and B7-1/B7-2 molecules expressed on dendritic cells could exert the secretion of cytokine IL-6, which may promote the production of autoantibody and aggravate Graves' disease. Therefore, aberrant elevation of plasma-soluble CD28 in patients with Graves' disease may reflect the dysregulation of immune system, and may serve as a useful biomarker in Graves' disease diagnosis.

Increased expression of costimulatory molecules CD86 and sCTLA-4 in patients with acute lymphoblastic leukemia

We herein evaluate the role of the B7-family molecule CD86 and the Cytotoxic T-lymphocyte-associated antigen-4 (CTLA-4) as a possible immunopathogenic factors in patients with ALL. The results of 60 patients with de novo ALL were compared to 40 controls. A significant statistical difference between CD86 expression and sCTLA-4 levels in patients versus their controls has been detected. During follow up period of 28 months, patients suffered from relapse (16 patients) had significantly higher CD86 expression and sCTL-4 levels compared to those remained in complete remission (44 patients) (p = 0.005 and 0.03 respectively). Patients who died from the disease (9 patients) showed significantly higher CD 86 expression and sCTLA-4 levels than surviving patients (51 patients) (p = 0.004 and 0.01 respectively). In conclusion, the higher levels of sCTLA-4 and CD86 in B-ALL patients might be candidate parameters for poor prognosis and may serve to refine treatment stratification with intensification of therapy in those patients prone to relapse.

The soluble form of CTLA-4 from serum of patients with autoimmune diseases regulates T-cell responses

Cytotoxic T lymphocyte associated antigen-4 (CTLA-4) is a costimulatory receptor transducing a potent inhibitory signal. Increasing evidence showed that CTLA-4 gene is an important susceptibility locus for autoimmune disorders. Alternatively spliced mRNA generates a soluble form, called sCTLA-4. Whereas low levels of sCTLA-4 are detected in normal human serum, increased/high serum levels are observed in several autoimmune diseases. The biological significance of increased sCTLA-4 serum level is not fully clarified yet. It can be envisaged that sCTLA-4 specifically inhibits the early T-cell activation by blocking the interaction of CD80/CD86 with the costimulatory receptor CD28. On the other hand, higher levels of sCTLA-4 could contend the binding of the membrane form of CTLA-4 with CD80/CD86, in later activation phase, causing a reduction of inhibitory signalling. We showed that sCTLA-4 from sera of patients with different autoimmune diseases is able to display functional activities on an in vitro system acting on the proliferation capability and modulating the secretion of cytokines. We observed a dual effect of sCTLA-4: inhibiting the secretion of IFN-γ, IL-2, IL-7, and IL-13 and activating the secretion of TGF-β and IL-10. This study underlines the role of sCTLA-4 in modulating the immune response and its relevance in autoimmune disease pathogenesis.

A genome-wide association study of total serum and mite-specific IgEs in asthma patients

Immunoglobulin E (IgE) is one of the central players in asthma and allergic diseases. Although the serum IgE level, a useful endophenotype, is generally increased in patients with asthma, genetic factors influencing IgE regulation in asthma are still not fully understood. To identify the genetic variations associated with total serum and mite-specific IgEs in asthmatics, a genome-wide association study (GWAS) of 657,366 single nucleotide polymorphisms (SNPs) was performed in 877 Korean asthmatics. This study found that several new genes might be associated with total IgE in asthmatics, such as CRIM1 (rs848512, P = 1.18×10⁻⁶; rs711254, P = 6.73×10⁻⁶), ZNF71 (rs10404342, P = 7.60×10⁻⁶), TLN1 (rs4879926, P = 7.74×10⁻⁶), and SYNPO2 (rs1472066, P = 8.36×10⁻⁶; rs1038770, P = 8.66×10⁻⁶). Regarding the association of specific IgE to house dust mites, it was observed that intergenic SNPs nearby to OPRK1 and LOC730217 might be associated with Dermatophagoides pteronyssinus (D.p.) and Dermatophagoides farinae (D.f.) in asthmatics, respectively. In further pathway analysis, the phosphatidylinositol signaling system and adherens junction pathways were estimated to play a role in the regulation of total IgE levels in asthma. Although functional evaluations and replications of these results in other populations are needed, this GWAS of serum IgE in asthmatics could facilitate improved understanding of the role of the newly identified genetic variants in asthma and its related phenotypes.

A soluble form of CTLA-4 is present in paediatric patients with acute lymphoblastic leukaemia and correlates with CD1d+ expression

CTLA-4 is a key factor in regulating and maintaining self tolerance, providing a negative signal to the T cell and thus limiting immune responses. Several polymorphisms within the CTLA-4 gene have been associated with an increased risk of developing autoimmune diseases and, very recently, with susceptibility to human cancer. Acute lymphoblastic leukemia is a clonal disorder of lymphoid progenitors representing the most frequent malignancy of childhood. Here, we show the presence at significantly elevated levels of a circulating soluble form of CTLA-4 in 70% of B-ALL pediatric patients with active disease, the positive correlation between the percentage of leukemic B lymphocytes and the amount of serum sCTLA-4, and the expression of sCTLA-4 transcript by B cells in patients. Finally, a correlation between CD1d expression (a negative prognostic marker) and the sCTLA-4 in B-ALL patients was observed. This suggests a possible role of this soluble molecule as a marker of progression or severity of the neoplastic disease.

Cytotoxic T-lymphocyte associated antigen 4 polymorphisms and asthma risk: a meta-analysis

Background

A number of studies assessed the association of cytotoxic T-lymphocyte associated antigen 4 (CTLA-4) gene polymorphisms with asthma in different populations. However, the results were contradictory. We performed a meta-analysis to examine the association between CTLA-4 polymorphisms and asthma susceptibility.

Methods

Pubmed, EMBASE, HuGE Navigator, and Wanfang Database were searched. Data were extracted independently by two reviewers. Odds ratios (ORs) with 95% confidence intervals (CIs) were used to assess the strength of associations.

Results

Seventeen studies involving 6378 cases and 8674 controls were included. Significant association between +49 A/G polymorphism and asthma was observed for AA vs. AG+GG (OR = 1.18, 95% CI 1.01–1.37, P = 0.04). There were no significant associations between −318 C/T, −1147 C/T, CT60 A/G, −1722 C/T, or rs926169 polymorphisms and asthma risk.

Conclusions

This meta-analysis suggested that the +49 A/G polymorphism in CTLA-4 was a risk factor for asthma.

Effects of different up-dosing regimens for hymenoptera venom immunotherapy on serum CTLA-4 and IL-10

Background

Cytotoxic T lymphocyte associated antigen-4 (CTLA-4) is involved in the activation pathways of T lymphocytes. It has been shown that the circulating form of CTLA-4 is elevated in patients with hymenoptera allergy and can be down regulated by immunotherapy.

Objective

to assess the effects on CTLA-4 of venom immunotherapy, given with different induction protocols: conventional (6 weeks), rush (3 days) or ultra rush (1 day).

Methods

Sera from patients with hymenoptera allergy were collected at baseline and at the end of the induction phase. CTLA-4 and IL-10 were assayed in the same samples. A subset of patients were assayed also after 12 months of VIT maintenance.

Results

Ninety-four patients were studied. Of them, 50 underwent the conventional induction, 20 the rush and 24 the ultra-rush. Soluble CTLA-4 was detectable in all patients at baseline, and significantly decreased at the end of the induction, irrespective of its duration. Of note, a significant decrease of sCTLA-4 could be seen already at 24 hours. In parallel, IL-10 significantly increased at the end of the induction. At 12 months, sCTLA-4 remained low, whereas IL-10 returned to the baseline values.

Conclusions

Serum CTLA4 is an early marker of the immunological effects of venom immunotherapy, and its changes persist after one year of maintenance treatment.

Effects of peripheral blood mononuclear cells morphology on vascular calcification in uremic patients on maintenance hemodialysis

We used high-resolution atomic force microscopy (AFM) to examine possible changes in the morphology of peripheral blood mononuclear cells (PBMCs), and to investigate their influence on vascular calcification in uremic patients on maintenance hemodialysis (MHD). 36 uremic patients had cardiovascular diseases after MHD (MHD group1) and 30 uremic patients did not (MHD group 2), and 20 healthy volunteers were the control group. The extent of coronary artery calcification was assessed with coronary artery calcification score (CACS). AFM was used to analyze PBMCs nuances. Concentrations of bone morphogenetic protein-2 (BMP-2) in PBMC supernatants were detected by ELISA. Protein expressions of BMP-2 were measured by Western blot. No significant differences in PBMC morphology were observed among groups by light microscopy. AFM images revealed that uremic patients exhibited significant differences of PBMC morphology and vascular calcification when compared with healthy volunteers. The PBMCs in uremic patients were larger in volume, mean height, half-maximum amplitude, average roughness and higher concentrations and expression of BMP-2 and CACS (P < 0.05), with granular processes or caveolae of uneven size distributed over cell surfaces. These differences were also significant between MHD group 1 and group 2 (P < 0.05). PBMC volume, mean height, half-maximum amplitude, and average roughness were positively correlated with BMP-2 and CACS. Moreover, the correlation PBMC with BMP-2 was higher than with CACS. PBMC morphology in MHD patients was related to the degree of vascular calcification. The larger mean height, half-maximum amplitude, average roughness and cell volume were, the higher degree of vascular calcification was.

Aberrant production of soluble co-stimulatory molecules CTLA-4 and CD28 in patients with chronic hepatitis B

Co-stimulation signals are critical for anti-viral immunity. Here we investigated whether there is altered expression and the clinical significance of soluble co-stimulatory molecules in patients with chronic HBV infection. Serum concentrations and ex vivo production of soluble CTLA-4, CD28, CD80 and CD86 were analyzed by enzyme-linked immunosorbent assay. Serum sCTLA-4 and sCD28 concentrations in all chronic HBV patients were significantly higher than concentrations in healthy control subjects. Serum sCTLA-4 and sCD28 correlated significantly with alanine aminotransferase in all chronic HBV patients. Upon mitogen stimulation of peripheral blood mononuclear cells, the percentage increases in ex vivo production of sCD28 and sCD80 and the percentage decrease in sCTLA-4 release were all significantly lower in chronic HBV patients than those in healthy subjects. The aberrant production of soluble co-stimulatory molecules should reflect the dysregulation of T cell activation and is related to the pathogenesis and severity of chronic HBV infection.

The soluble CTLA-4 receptor and its role in autoimmune diseases: an update

CTLA-4, initially described as a membranebound molecule, is a costimulatory receptor transducing a potent inhibitory signal. Increasing evidence shows the CTLA-4 gene to be an important susceptibility locus for autoimmune endocrinopathies and other autoimmune disorders. A soluble form of cytotoxic T-lymphocyte-associated antigen-4 (sCTLA-4) has been established and shown to possess CD80/CD86 binding activity and in vitro immunoregulatory functions. sCTLA-4 is generated by alternatively spliced mRNA. Whereas low levels of sCTLA-4 are detected in normal human serum, increased serum levels are observed in several autoimmune diseases (e.g. Graves’ disease, myasthenia gravis, systemic lupus erythematosus, type 1 diabetes, systemic sclerosis, coeliac disease, autoimmune pancreatitis and primary biliary cirrhosis). The biological significance of increased sCTLA-4 serum levels is not fully clarified yet. On the one hand, it can be envisaged that sCTLA-4 specifically inhibits early T-cell activation by blocking the interaction of CD80/CD86 with the costimulatory receptor CD28. On the other hand, higher levels of sCTLA-4 could compete for the binding of the membrane form of CTLA-4 with CD80/CD86 in the later phases of T-lymphocyte activation, causing a reduction in inhibitory signalling. This double-edged nature of sCTLA-4 to block the binding of CD28 to CD80/CD86 may result in different outcomes during the clinical course of an autoimmune disease.

Endotoxin tolerance attenuates airway allergic inflammation in model mice by suppression of the T-cell stimulatory effect of dendritic cells

Prior exposure of dendritic cells (DCs) and monocytes/macrophages to LPS causes unresponsiveness to subsequent LPS stimulation, a phenomenon called endotoxin tolerance (ET). ET impairs antigen presentation of these cells to T cells by down-regulating expression of MHC class II and co-stimulatory molecules such as CD86 and CD40. Some epidemiological studies have shown that endotoxin acts as a protective factor for allergic diseases. Accordingly, LPS has beneficial effects on the onset of airway allergic inflammation in model animals by T(h)1 skewing or induction of regulatory T cells. However, results derived from asthma model animals are controversial, probably due to the difficulty of handling LPS. We previously generated a monoclonal agonistic antibody against Toll-like receptor (TLR) 4, named UT12, which mimics the biological activities of LPS, exhibiting more potent and sustained ET than does LPS. In this study, we took advantage of UT12 to generate prolonged ET to explore the possibility that ET is involved in the inhibitory effects of the TLR4 signals on asthma model mice. Induction of ET by UT12 inhibited the capacity of DCs to expand ovalbumin (OVA)-specific T(h)2 and T(h)17 cells, without inducing T(h)1 cell or regulatory T-cell populations or producing inhibitory cytokines. Accordingly, administration of UT12 before the OVA sensitization significantly suppressed airway allergic inflammation by OVA inhalation. Taken together, these results demonstrate that ET induced by activating TLR4 signals attenuates airway allergic inflammation through direct suppression of the T-cell stimulatory effect of DCs in asthma model mice.

Surface markers of lymphocyte activation in pregnant asthmatics

PROBLEM

Pregnancy-associated immunologic alterations may improve the course of asthma. Severe maternal asthma with an exacerbation impairs fetal growth.

METHOD OF STUDY

Lymphocyte activation was estimated by flow cytometry analysis of surface markers in non-pregnant healthy and mild or moderate persistent asthmatic women and healthy as well as mild or moderate persistent asthmatic, third trimester pregnant women.

RESULTS

Compared with non-pregnant healthy subjects (n = 12) activated pools within CD4 and CD8 T cells were larger and the number of NK T cells were increased both in non-pregnant asthmatic (n = 12) and in healthy pregnant (n = 13) subjects (all p\0.05). No further lymphocyte activation was observed in pregnant asthmatics (n = 21) compared either with non-pregnant asthmatic, or pregnant healthy women. Average birth weight of newborns was lower (p\0.05) in the asthmatic than in the healthy pregnant group.

CONCLUSION

Pregnancy is a state of wide-spread lymphocyte activation but it may blunt lymphocyte activation which characterizes bronchial asthma.

Biochemical analysis of CTLA-4 immunoreactive material from human blood

Background

CTLA-4 was initially described as a membrane-bound molecule that inhibited lymphocyte activation by interacting with B7.1 and B7.2 molecules on antigen presenting cells. Alternative splicing of mRNA encoding the CTLA-4 receptor leads to the production of a molecule (sCTLA-4) that lacks a membrane anchor and is therefore secreted into the extracellular space. Despite studies finding that people with autoimmune disease more frequently express high levels of sCTLA-4 in their blood than apparently healthy people, the significance of these findings is unclear.

Methods

Molecules isolated from blood using CTLA-4 specific antibodies were analyzed with ligand binding assays, mass spectroscopy, and biochemical fractionation in an effort to increase our understanding of CTLA-4 immunoreactive material.

Results

Mass spectroscopy analysis of the molecules recognized by multiple CTLA-4-specific antibodies failed to identify any CTLA-4 protein. Even though these molecules bind to the CTLA-4 receptors B7.1 and B7.2, they also exhibit properties common to immunoglobulins.

Conclusion

We have identified molecules in blood that are recognized by CTLA-4 specific antibodies but also exhibit properties of immunoglobulins. Our data indicates that what has been called sCTLA-4 is not a direct product of the CTLA-4 gene, and that the CTLA-4 protein is not part of this molecule. These results may explain why the relationship of sCTLA-4 to immune system activity has been difficult to elucidate.

Lack of association between sCTLA-4 levels in human plasma and common CTLA-4 polymorphisms

BACKGROUND

Cytotoxic T lymphocyte antigen-4 (CTLA-4) is an important downregulatory molecule expressed on both T and B lymphocytes. Numerous population genetics studies have documented significant associations between autoimmune diseases and single nucleotide polymorphisms (SNPs) within and around the CTLA-4 region of chromosome 2 in man. Furthermore, circulating levels of a soluble form of CTLA-4 (sCTLA-4) have been reported in a variety of autoimmune mediated diseases. Despite these findings, the relationship between levels of sCTLA-4 protein, mRNA transcript levels, and SNPs within the CTLA-4 region have not been clearly defined. In order to further clarify this relationship, we have tested four different SNPs within the CTLA-4 region among subjects whom are negative (n = 53) versus positive (n = 28) for sCTLA-4.

RESULTS

Our data do not support a clear association between sCTLA-4 levels and any of the four SNPs tested.

CONCLUSION

The variation in the SNPs tested does not appear to effect sCTLA-4 protein levels, despite reports that they affect sCTLA-4 mRNA.

Therapeutic effects of anti-B7-1 antibody in an ovalbumin-induced mouse asthma model

Allergic asthma is a chronic inflammatory disorder of airways, which is characterized by attacks provoked by exposure to so-called asthma triggers, such as pet dander, second-hand tobacco smoke, dust mites, and mold spores. B7-1 (CD80), perhaps one of the most studied co-stimulatory molecules involved in asthma, plays a key role in regulating allergen-induced T cell activation in asthma, probably through T cell recruitment and Th cell differentiation upon allergen provocation. The present study was designed to test the hypothesis that anti-B7-1 antibody has therapeutic effects in asthma by blocking B7-1/CD28 pathway. The asthma model was established by ovalbumin (OVA) sensitization and challenging in female Balb/c mice. One hour after the last induction, mice were sacrificed and whole lung lavage was conducted. Cell numbers in bronchoalveolar lavage fluid (BALF) were determined and the expression levels of IFN-gamma and IL-4 in supernatant were measured by an enzyme-linked immunosorbent assay method. Sedimental cells smears were stained with Wright's-Gimsa mixed coloring method. The B7-1 expression was detected by immunohistochemistry method with frozen tissue sections. The anti-B7-1 antibody treatment could alleviate asthmatic syndromes induced by OVA. The number of recoverable eosinophils in BALF in the anti-B7-1 antibody treated group was significantly lower than that in the control group (P<0.01) and the eosinophils peribronchial infiltration was remarkably reduced in anti-B7-1 treated asthmatic mice, based on histological evaluation. The treatment with the anti-B7-1 antibody induced IFN-gamma expression and decreased IL-4 expression, compared with the asthmatic control group (P<0.01). In conclusion, the anti-B7-1 antibody approach may provide a novel therapy for allergic asthma.

Heme oxygenase-1 attenuates ovalbumin-induced airway inflammation by up-regulation of foxp3 T-regulatory cells, interleukin-10, and membrane-bound transforming growth factor- 1

Cumulative evidence suggests the up-regulation of interleukin (IL)-10 and T-regulatory (Treg) cells is implicated in anti-inflammatory effect of heme oxygenase-1 (HO-1). Thus, we postulated that induction of HO-1 could augment IL-10 and transforming growth factor (TGF)-beta production and foxp3+CD4+CD25+ Treg cell function, thereby leading to attenuation of airway inflammation. In this study, CD4+CD25+ Treg cells isolated from mouse spleen were either transfected with a HO-1 expression vector (pcDNA3HO-1) or treated with a HO-1 inducer (hemin). Up-regulation of HO-1 enhanced foxp3 expression and IL-10 secretion in the Treg cells in vitro. Next, BALB/c, C57/B6.129, and IL-10-deficient B6.129P2-Il10tm1Cgn/J mice were challenged by ovalbumin to induce airway inflammation. Consistent with in vitro findings, hemin treatment resulted in induction of HO-1 and foxp3 and production of IL-10 and membrane-bound TGF-beta1 in vivo. This was further correlated with decrease of ovalbumin-specific immunoglobulin E level and eosinophil infiltration in bronchial alveolar lavage fluid from the asthmatic mice. Furthermore, hemin significantly enhanced the biological activity of CD4+CD25+ Treg cells. This protective effect was specifically blocked by Sn-protoporphyrin, a HO-1 enzymatic inhibitor. Finally, hemin failed to up-regulate the function of CD4+CD25+ Treg cells from IL-10-deficient mice. Our study indicates that HO-1 exerts its protective effect on asthma through a mechanism mediated by foxp3+CD4+CD25+ Treg cells, IL-10, and membrane-bound TGF-beta1.

Intracellular JNK, p38 MAPK and NF-kappaB regulate IL-25 induced release of cytokines and chemokines from costimulated T helper lymphocytes

Novel Th2 cytokine IL-25 has been shown to be elevated in allergic inflammation. We investigated the intracellular mechanisms regulating IL-25-induced Th2 cytokines and chemokines from human Th lymphocytes upon costimulation by anti-CD3 and anti-CD28 antibodies. Cytokines, chemokines, and phosphorylated p38 mitogen activated protein kinases (MAPK), c-Jun amino-terminal kinase (JNK) and extracellular signal-regulated protein kinase were analyzed by bead-based array using flow cytometry. Nuclear factor (NF)-kappaB and total MAPK were assessed by electrophoretic mobility shift assay and Western blot, respectively. IL-25 could synergistically induce the release of Th2 cytokines IL-4, IL-5 and IL-10, inflammatory cytokine IL-6, Th1 related chemokines CXCL9 and CXCL10, and chemokine CCL5 from anti-CD3 and anti-CD28 antibodies costimulated Th cells, especially memory Th cells. Costimulation could also upregulate the cell surface expression of IL-25 receptor on Th cells. Costimulation with or without IL-25 treatment could activate JNK, p38 MAPK and NF-kappaB. The upregulation of costimulation-induced IL-25 receptors and release of cytokines and chemokines from IL-25 treated costimulated Th cells were differentially regulated by intracellular JNK, p38 MAPK and NF-kappaB activity. Therefore, the optimal activation of Th cells by IL-25 for the release of Th2 cytokines and chemokines requires the CD3 and CD28 mediated costimulation of Th cells via the upregulation of IL-25 receptors and the activation of intracellular signaling pathways. This mechanistic study shows that IL-25 and CD28 costimulation can play pathophysiological roles by inducing inflammation and hyperresponsiveness through the production of both Th2 cytokines and chemokines from memory Th cells.

Increased expression of plasma and CD4+ T lymphocyte costimulatory molecule CD26 in adult patients with allergic asthma

CD26, which is a costimulatory molecule and peptidase, is responsible for the degradation of interferon (IFN)-gamma-induced chemokines. To elucidate the immunopathological role of CD26 in allergic asthma, we investigated plasma soluble CD26 (sCD26) concentration and its cell surface expression on lymphocytes, monocytes, CD4+ T helper, CD8+ T suppressor plus cytotoxic T, invariant natural killer T (iNKT), and CD19+ B lymphocytes in allergic asthmatic patients. Plasma sCD26 was significantly elevated in asthmatic patients regardless of inhaled corticosteroid treatment (all P < 0.05). Cell surface expression of CD26 was significantly up-regulated on lymphocytes, especially on CD4+ and iNKT lymphocytes (all P < 0.05), but not on other cell types. Significant positive correlations were found between sCD26 and the percentage of eosinophils, Th2-related chemokines CCL5 and CCL22, and costimulatory molecule sCTLA-4 (all P < 0.05). In conclusion, the aberrant expression of CD26 may contribute to the inflammatory process and Th2 predominance in the immunopathogenesis of allergic asthma.

Soluble CTLA-4 in autoimmune thyroid diseases: relationship with clinical status and possible role in the immune response dysregulation

CTLA-4 molecule, expressed by activated T and B lymphocytes, transduces an inhibitory signal. Increasing evidence showed CTLA-4 gene as an important susceptibility locus for autoimmune endocrinopathies and other autoimmune disorders. The aim is to evaluate the augmented sCTLA-4 serum levels in different autoimmune thyroid diseases when compared with normal donors or with non-autoimmune hyperthyroidism and to investigate the functional activities and suggest the possible pathogenetic role of sCTLA-4. We demonstrate the presence of a soluble form of CTLA-4 in 59/90 sera from patients with autoimmune thyroid diseases (both Graves' disease and autoimmune thyroiditis). sCTLA-4 levels were not related to specific clinical manifestations, such as clinical thyroid status (hypo- or hyperthyroidism), circulating thyroid hormones, or other clinical features (ophthalmopathy). sCTLA-4 production does not seem to be affected by disease evolution during time. We showed that sCTLA-4 from sera of patients with thyroid autoimmunity is able to bind its physiological ligands CD80/CD86 and displays functional activities on different in vitro systems (T-cell proliferation induced by specific soluble antigens, bi-directional mixed lymphocyte reaction). In conclusion, we demonstrate an increment of sCTLA-4 in serum of patients with autoimmune thyroid diseases. Its possible pathogenetic role during autoimmune processes can be speculated: sCTLA-4 can specifically inhibit the early T-cell activation by blocking the interaction of CD80/CD86 with the co-stimulatory receptor CD28. Conversely, higher levels of sCTLA-4 could compete with membrane-bound CTLA-4 for CD80/CD86, in later T lymphocytes activation phase, causing a reduction of inhibitory signaling.

A negative regulatory role in mouse cardiac transplantation for a splice variant of CD80

BACKGROUND

Members of the B7 costimulatory protein family (CD80 and CD86) play a determining role in allograft rejection. Both CD80 and CD86 have naturally occurring splice variants whose roles in transplantation are unknown. Full length CD80 has two immunoglobulin (Ig)-like domains in the extracellular portion, IgC and IgV. In mouse, the isoform IgV-CD80 lacks the IgC-like domain. Here we analyzed the role of mouse IgV-CD80 in heart allograft rejection and search for equivalent splice variants in human.

METHODS

Mice made deficient for full-length CD80 but which retain expression of the shorter IgV-CD80 (CD80 mice) were used as donor or recipient of a heart allograft. Recipient animals were untreated or pretreated with alloantigen expressing cells and/or treated with CD80 and CTLA4 monoclonal antibodies (mAbs).

RESULTS

Recipients expressing IgV-CD80 but not full length CD80 exhibited a slight prolongation in survival of either wild-type (Wt) or CD80 grafts. More dramatically, CD80 animals pretreated with donor alloantigen exhibited permanent graft survival, whereas their Wt counterparts rejected their grafts with a median survival of 24 days. This prolonged survival was due to the expression of IgV-CD80 in recipients since treatment with CD80 mAb abrogated the beneficial effect observed. We identified and report here a similar isoform of CD80 from human cDNA encoding a putative soluble, IgV-containing protein.

CONCLUSIONS

IgV-CD80 bearing recipients show enhanced allograft survival especially after donor alloantigen pretreatment. This together with data from other species suggests that regulation delivered by splice variants of CD80 significantly modulates immunity and may be common across the species.

Distribution of CTLA-4 polymorphisms in allergic asthma

BACKGROUND

The CTLA-4 molecule is an important negative regulator of T cell activation. It is encoded on chromosome 2q33 and found to be associated with several allergic phenotypes including asthma. However, the association of CTLA-4 gene polymorphisms with allergic asthma is still controversial and therefore was the subject of this study.

METHODS

By PCR-RFLP, the distribution of three single nucleotide polymorphisms (SNPs), -1147 C/T, -318 C/T, and +49 A/G, was examined in 219 Polish Caucasoid patients diagnosed with allergic asthma and in 102 ethnically matched healthy control individuals. (AT)(n) microsatellite polymorphism was also tested in the same individuals.

RESULTS

No statistically significant differences in SNPs or microsatellite allele, genotype or haplotype frequencies between patients and controls were found.

CONCLUSION

CTLA-4 polymorphisms do not seem to be a risk factor for allergic asthma in Poles.

CTLA-4 gene polymorphisms and natural soluble CTLA-4 protein in psoriasis vulgaris

CTLA-4 molecule is an important inhibitor of T-lymphocyte activation. Several single nucleotide polymorphisms (SNPs) in the CTLA-4 gene were found, and their associations with many human diseases were described. So far, however, such studies have not been performed in psoriasis vulgaris in Caucasoids. Therefore, we examined the distribution of three CTLA-4 SNPs: -1147C/T, -318C/T and +49 A/G in 116 patients with psoriasis vulgaris and 123 healthy blood donors using the polymerase chain reaction-restriction fragment length polymorphism method. For all three SNPs, the frequencies of alleles, genotypes and three-point haplotypes were very similar in patients and controls, suggesting no contribution of these genetic variants to psoriasis.

Plasma concentrations of soluble CTLA-4, CD28, CD80 and CD86 costimulatory molecules reflect disease severity of acute asthma in children

Recent studies have demonstrated an elevation of plasma soluble costimulatory molecules B7.1 (CD80) and B7.2 (CD86), and their T lymphocyte counter receptors cytotoxic T lymphocyte associated antigen-4 (CTLA-4) and CD28 in asthmatic patients. We hypothesized that these costimulatory molecules may reflect the severity of asthma and investigated the longitudinal changes of these soluble costimulatory molecules, and their clinical significance in children with an asthmatic exacerbation. Sixteen children hospitalized for asthmatic exacerbation were recruited and treated with systemic corticosteroid (CS) for 5 days. Plasma total Immunoglobulin E (IgE) and eosinophil cationic protein (ECP) concentrations were measured by microparticle immunoassay and fluorescence enzyme immunoassay, respectively. Soluble CTLA-4 (sCTLA-4), sCD28, sCD80, and sCD86 concentrations in plasma were measured by enzyme-linked immunosorbent assay, and their relationships with asthma severity, total IgE, ECP concentrations, and blood eosinophil count were analyzed. Plasma sCTLA-4, sCD28, sCD80, and sCD86 concentrations in patients were highest during the acute attack. They decreased significantly with a parallel increase of peak expiratory flow rate (PEFR) after CS treatment (all P < 0.05). Plasma sCTLA-4, sCD28, and sCD86 concentrations of patients at recruitment were inversely correlated with PEFR, whereas plasma sCD28 and sCD86 concentrations correlated positively with eosinophil count and plasma ECP concentration (all P < 0.05). Although there was no such correlation with IgE concentration, sCD28 was correlated very significantly with eosinophil count (r = 0.83, P < 0.0001). In conclusion, plasma sCTLA-4, sCD28, sCD86, and sCD80 concentrations may reflect the severity of acute asthma and more studies on larger cohorts are needed to assess whether these markers are useful for assessing asthmatic exacerbation in children.

CD28/CTLA-4--CD80/CD86 and ICOS--B7RP-1 costimulatory pathway in bronchial asthma

Costimulatory molecules are cell surface glycoproteins that can direct, modulate and fine-tune T-cell receptor signals. The B7-1/B7-2--CD28/CTLA-4 and ICOS-B7RP-1 pathway provides key second signals that can regulate the activation, inhibition and fine-tuning of T-lymphocyte responses. The expression of B7-1/B7-2--CD28/CTLA-4 molecules on clinical samples from patients with asthma have been well studied, and the results indicate that different extents of these molecules are expressed on the surface of various cells, and that the concentrations of soluble form of these molecules are elevated in the sera of patients with asthma. There is a burst of papers describing an important role for B7-1/B7-2--CD28/CTLA-4 pathway in the Th1/Th2 balance. Similarly, ICOS stimulates both Th1 and Th2 cytokine production but may have a preferential role in Th2 cell development. Moreover, The B7-1/B7-2-CD28/CTLA-4 and ICOS-B7RP-1 pathway has been suggested of being involved in the development of airway inflammation and airway hyperresponsiveness. Further study of the functions of the pathways within the CD28/CTLA-4--CD80/CD86 and ICOS--B7RP-1 superfamily individually and their interplay should provide insights into the pathogenesis of asthma, and has great therapeutic potential for treatment of asthma.