Detection of circulating soluble CD28 in patients with systemic lupus erythematosus, primary Sjögren's syndrome and systemic sclerosis

The Current and Future of Biomarkers of Immune Related Adverse Events

With their groundbreaking clinical responses, immune checkpoint inhibitors (ICIs) have ushered in a new chapter in cancer therapeutics. However, they are often associated with life-threatening or organ-threatening autoimmune/autoinflammatory phenomena, collectively termed immune-related adverse events (irAEs). In this review, we will first describe the mechanisms of action of ICIs as well as irAEs. Next, we will review biomarkers for predicting the development of irAEs or stratifying risks.

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.

Cytokines/chemokines and soluble immune checkpoint molecules in anti-GABAB receptor encephalitis

BACKGROUND

Anti-gamma-aminobutyric-acid B receptor (anti-GABA_BR) encephalitis is a rare form of autoimmune limbic encephalitis (ALE) that is closely associated with tumor comorbidity. The purpose of this study is to identify the expressive pattern of cytokines/ chemokines and soluble immune checkpoint molecules (sICMs) in anti-GABA_BR encephalitis in order to evaluate the clinical condition and provide new treatment options.

METHODS

A total of 40 cytokines/chemokines and 10 sICMs in the serum of 10 patients with anti-GABA_BR encephalitis and eight controls were measured. The differentially expressed cytokines/chemokines and sICMs were selected to explore the correlations with disease prognosis, CSF routine and antibody titers.

RESULTS

Eight cytokines/chemokines were found to be more abundant in patients than in healthy donors (HDs), while 14 were found to be less abundant in patients. In terms of sICMs, patients' serum contained higher level of soluble ICOS and ICOSL but lower level of soluble CD86. Unfavorable prognosis was associated with high serum level of PDGFB, IL-17A, and soluble ICOSL but not with low levels of IL-4. Increased levels of IL-17A, CCL15, and soluble ICOS were found frequently in the patients with CSF-exclusive OCBs, while soluble ICOSL and CCL24 expression was lower in these patients. High levels of IL-1 F2 and TCA-3 were correlated with the presence of tumors in patients.

CONCLUSION

The majority of patients with anti- GABA_BR encephalitis had an unfavorable prognosis in one year of follow-up. Serum PDGFB, IL-17A, IL-4 and soluble ICOSL level were associated with the poor clinical outcomes in one-year follow up.

Pregnancy induces pancreatic insulin secretion in women with long-standing type 1 diabetes

INTRODUCTION

Pregnancy entails both pancreatic adaptations with increasing β-cell mass and immunological alterations in healthy women. In this study, we have examined the effects of pregnancy on β-cell function and immunological processes in long-standing type 1 diabetes (L-T1D).

RESEARCH DESIGN AND METHODS

Fasting and stimulated C-peptide were measured after an oral glucose tolerance test in pregnant women with L-T1D (n=17) during the first trimester, third trimester, and 5-8 weeks post partum. Two 92-plex Olink panels were used to measure proteins in plasma. Non-pregnant women with L-T1D (n=30) were included for comparison.

RESULTS

Fasting C-peptide was detected to a higher degree in women with L-T1D during gestation and after parturition (first trimester: 64.7%, third trimester: 76.5%, and post partum: 64.7% vs 26.7% in non-pregnant women). Also, total insulin secretion and peak C-peptide increased during pregnancy. The plasma protein levels in pregnant women with L-T1D was dynamic, but few analytes were functionally related. Specifically, peripheral levels of prolactin (PRL), prokineticin (PROK)-1, and glucagon (GCG) were elevated during gestation whereas levels of proteins related to leukocyte migration (CCL11), T cell activation (CD28), and antigen presentation (such as CD83) were reduced.

CONCLUSIONS

In summary, we have found that some C-peptide secretion, that is, an indirect measurement of endogenous insulin production, is regained in women with L-T1D during pregnancy, which might be attributed to elevated peripheral levels of PRL, PROK-1, or GCG.

Exploiting the role of T cells in the pathogenesis of Sjögren's syndrome for therapeutic treatment

Sjögrens syndrome (SS) is caused by autoantibodies that attack proprioceptive salivary and lacrimal gland tissues. Damage to the glands leads to dry mouth and eyes and affects multiple systems and organs. In severe cases, SS is life-threatening because it can lead to interstitial lung disease, renal insufficiency, and lymphoma. Histological examination of the labial minor salivary glands of patients with SS reveals focal lymphocyte aggregation of T and B cells. More studies have been conducted on the role of B cells in the pathogenesis of SS, whereas the role of T cells has only recently attracted the attention of researchers. This review focusses on the role of various populations of T cells in the pathogenesis of SS and the progress made in research to therapeutically targeting T cells for the treatment of patients with SS.

Circulating immune profile can predict survival of metastatic uveal melanoma patients: results of an exploratory study

Metastatic uveal melanoma (UM) is a poor prognosis malignancy. Immunotherapy is commonly employed, despite the low activity, considering the lack of other effective systemic treatments. In this study, the prognostic and predictive role of soluble immune checkpoints and inflammatory cytokines/chemokines in 22 metastatic UM patients was evaluated. Baseline levels of these molecules were assessed, as well as their changes during anti-PD-1 therapy. The correlation between soluble immune checkpoints/cytokines/chemokines and survival was analyzed. A comparison between circulating immune profile of metastatic cutaneous melanoma (CM), for which immunotherapy is a mainstay of treatment, and UM during anti-PD-1 therapy was also performed. Three immune molecules resulted significantly higher in metastatic UM patients with survival <6 months versus patients with survival ≥6 months: IL-8, HVEM and IDO activity. Considering these three molecules, we obtained a baseline score able to predict patients’ survival. The same three molecules, together with soluble(s) CD137, sGITR and sCD27, resulted significantly lower in patients with survival >30 months. We also observed an increase of sCD137, sCD28, sPD-1, sPD-L2 sLAG3, sCD80 and sTim3 during anti-PD-1 treatment, as well as IDO activity, IP-10 and CCL2. Several of these molecules were significantly higher in UM compared to CM patients during anti-PD-1 therapy. The analysis of circulating immune molecules allows to identify patients with poor prognosis despite immunotherapy and patients with long survival treated with an anti-PD-1 agent. The different serum concentration of these molecules during anti-PD-1 therapy between UM and CM reflects the different efficacy of immune checkpoint inhibitors.

sCD28, sCD80, sCTLA-4, and sBTLA Are Promising Markers in Diagnostic and Therapeutic Approaches for Aseptic Loosening and Periprosthetic Joint Infection

Aseptic prosthetic loosening and periprosthetic joint infections (PJI) are among the most frequent complications after total knee/hip joint arthroplasty (TJA). Current research efforts focus on understanding the involvement of the immune system in these frequent complications. Different immune cell types have already been implicated in aseptic prosthetic loosening and PJI. The aim of this study was to systematically analyze aspirates from knee and hip joints, evaluating the qualitative and quantitative composition of soluble immunoregulatory markers, with a focus on co-inhibitory and co-stimulatory markers. It has been shown that these molecules play important roles in immune regulation in cancer and chronic infectious diseases, but they have not been investigated in the context of joint replacement. For this purpose, aspirates from control joints (i.e., native joints without implanted prostheses), joints with TJA (no signs of infection or aseptic loosening), joints with aseptic implant failure (AIF; i.e., aseptic loosening), and joints with PJI were collected. Fourteen soluble immunoregulatory markers were assessed using bead-based multiplex assays. In this study, it could be shown that the concentrations of the analyzed immunoregulatory molecules vary between control, TJA, AIF, and PJI joints. Comparing TJA patients to CO patients, sCD80 was significantly elevated. The marker sBTLA was significantly elevated in AIF joints compared to TJA joints. In addition, a significant difference for eight markers could be shown when comparing the AIF and CO groups (sCD27, sCTLA-4, sCD137, sCD80, sCD28, sTIM-3, sPD-1, sBTLA). A significant difference was also reached for nine soluble markers when the PJI and CO groups were compared (sLAG-3, sCTLA-4, sCD27, sCD80, sCD28, sTIM-3, sPD-1, IDO, sBTLA). In summary, the analyzed immunoregulatory markers could be useful for diagnostic purposes as well as to develop new therapeutic approaches for AIF and PJI.

Checkpoint Molecules in Rheumatology-or the Benefits of Being Exhausted

PURPOSE OF REVIEW

This review will focus on the most common co-inhibitory molecules, emphasizing the importance of these in relation to rheumatic disease.

RECENT FINDINGS

Checkpoint molecules are pivotal in determining the outcome of antigen activation. Checkpoint molecules consist of co-stimulatory and co-inhibitory molecules, where the first activates and the latter inhibits the antigen presentation process. Studies show that increased activity of co-inhibitory molecules is associated with a good prognosis in rheumatic diseases. Opposite, when cancer patients are treated with antibodies blocking the inhibitory pathways, autoimmune diseases, including arthritis, develop as immune-related adverse events (IrAE). This emphasizes the importance of these pathways in autoimmune disease. Co-inhibitory molecules are becoming increasingly interesting as future treatment targets in rheumatic conditions. Treatments with antibodies blocking these pathways result in IrAE, often manifesting as autoimmune rheumatic diseases. Therefore, a need to get acquainted with these molecules is growing so we can cope with future challenges in rheumatic diseases.

CD8+ T Lymphocytes: Crucial Players in Sjögren's Syndrome

Primary Sjögren's syndrome (pSS) is a chronic autoimmune disease associated with damage to multiple organs and glands. The most common clinical manifestations are dry eyes, dry mouth, and enlarged salivary glands. Currently, CD4+ T lymphocytes are considered to be key factors in the immunopathogenesis of pSS, but various studies have shown that CD8+ T lymphocytes contribute to acinar injury in the exocrine glands. Therefore, in this review, we discussed the classification and features of CD8+ T lymphocytes, specifically describing the role of CD8+ T lymphocytes in disease pathophysiology. Furthermore, we presented treatment strategies targeting CD8+ T cells to capitalize on the pathogenic and regulatory potential of CD8+ T lymphocytes in SS to provide promising new strategies for this inflammatory disease.

Magnetic bead extraction with acid dissociation immunoassay for the determination of serum CD80-Fc fusion protein

Background: To detect concentrations of subtherapeutic doses of the CD80-Fc fusion protein FPT155 in serum in Phase I studies, a highly sensitive assay was developed. Materials & methods: FPT155 was purified from human serum using magnetic beads coupled to cytotoxic T-lymphocyte-associated antigen-4. After washing away the serum components, FTP155 was released by acid dissociation and neutralization. The eluted drug was quantified in an ELISA using cytotoxic T-lymphocyte-associated antigen-4 as a capture reagent and biotinylated anti-human Fc for detection. The assay was validated with a calibration range of 5-40 ng/ml and a dilutional integrity of up to 100,000 ng/ml. Conclusion: A highly sensitive assay to determine serum concentrations of FPT155 using readily available reagents was developed. The results were in conformity with theoretical calculations.

Delicate Role of PD-L1/PD-1 Axis in Blood Vessel Inflammatory Diseases: Current Insight and Future Significance

Immune checkpoint molecules are the antigen-independent generator of secondary signals that aid in maintaining the homeostasis of the immune system. The programmed death ligand-1 (PD-L1)/PD-1 axis is one among the most extensively studied immune-inhibitory checkpoint molecules, which delivers a negative signal for T cell activation by binding to the PD-1 receptor. The general attributes of PD-L1's immune-suppressive qualities and novel mechanisms on the barrier functions of vascular endothelium to regulate blood vessel-related inflammatory diseases are concisely reviewed. Though targeting the PD-1/PD-L1 axis has received immense recognition-the Nobel Prize in clinical oncology was awarded in the year 2018 for this discovery-the use of therapeutic modulating strategies for the PD-L1/PD-1 pathway in chronic inflammatory blood vessel diseases is still limited to experimental models. However, studies using clinical specimens that support the role of PD-1 and PD-L1 in patients with underlying atherosclerosis are also detailed. Of note, delicate balances in the expression levels of PD-L1 that are needed to preserve T cell immunity and to curtail acute as well as chronic infections in underlying blood vessel diseases are discussed. A significant link exists between altered lipid and glucose metabolism in different cells and the expression of PD-1/PD-L1 molecules, and its possible implications on vascular inflammation are justified. This review summarizes the most recent insights concerning the role of the PD-L1/PD-1 axis in vascular inflammation and, in addition, provides an overview exploring the novel therapeutic approaches and challenges of manipulating these immune checkpoint proteins, PD-1 and PD-L1, for suppressing blood vessel inflammation.

CD28 gene polymorphisms and acute cellular rejection after liver transplantation

The co-stimulatory molecule CD28 plays an important role in T-cell-mediated immune response like acute cellular liver transplant rejection. The aim of the retrospective case- control study was to examine whether the single nucleotide polymorphisms (SNPs) rs3116487, rs3116494, and rs3116496 of the CD28 gene are associated with acute cellular liver transplant rejection. The mentioned SNPs were genotyped in 147 liver transplant recipients without acute cellular rejection and 144 liver transplant recipients with acute cellular rejection by real-time endpoint genotyping. The genotype and allele frequencies of the SNPs did not show any significant differences between both groups. Haplotype analyzes of the SNPs also showed no association. Our data suggest that the analyzed SNPs are not major contributors to the susceptibility of acute cellular liver transplant rejection.

Non-signaling Chimeric Antigen Receptors Enhance Antigen-Directed Killing by γδ T Cells in Contrast to αβ T Cells

Chimeric antigen receptor (CAR)-modified T cells have demonstrated efficacy against B cell leukemias/lymphomas. However, redirecting CAR T cells to malignant T cells is more challenging due to product-specific cis- and trans-activation causing fratricide. Other challenges include the potential for product contamination and T cell aplasia. We expressed non-signaling CARs (NSCARs) in γδ T cells since donor-derived γδ T cells can be used to prevent product contamination, and NSCARs lack signaling/activation domains, but retain antigen-specific tumor cell-targeting capability. As a result, NSCAR targeting requires an alternative cytotoxic mechanism, which can be achieved through utilization of γδ T cells that possess major histocompatibility complex (MHC)-independent cytotoxicity. We designed two distinct NSCARs and demonstrated that they do not enhance tumor-killing by αβ T cells, as predicted. However, both CD5-NSCAR- and CD19-NSCAR-modified γδ T cells enhanced cytotoxicity against T and B cell acute lymphoblastic leukemia (T-ALL and B-ALL) cell lines, respectively. CD5-NSCAR expression in γδ T cells resulted in a 60% increase in cytotoxicity of CD5-expressing T-ALL cell lines. CD19-NSCAR-modified γδ T cells exhibited a 350% increase in cytotoxicity against a CD19-expressing B-ALL cell line compared to the cytotoxicity of naive cells. NSCARs may provide a mechanism to enhance antigen-directed anti-tumor cytotoxicity of γδ T cells through the introduction of a high-affinity interaction while avoiding self-activation.

Abnormal membrane-bound and soluble programmed death ligand 2 (PD-L2) expression in systemic lupus erythematosus is associated with disease activity

Programmed death ligand (PD-L) 2 and PD-L1 are the second and first ligands, respectively, for programmed cell death-1 protein (PD-1), which is one of the key factors responsible for inhibitory T cell signaling, mediating mechanisms of tolerance and providing immune homeostasis. Studies have shown that PD-1 and its ligand PD-L1 are abnormally expressed in autoimmune diseases, such as rheumatoid arthritis and autoimmune hepatitis, but its other ligand, PD-L2, has rarely been studied. This study analyzed the changes in membrane-bound PD-L2 expression in peripheral blood mononuclear cells and soluble PD-L2 (sPD-L2) levels in the serum of patients with systemic lupus erythematosus (SLE) to explore the relationship between PD-L2 expression with disease activity and related test parameters. Our results showed that membrane-bound PD-L2 expression on monocytes was significantly higher and the sPD-L2 levels were significantly lower in SLE patients than in healthy subjects. Patients with active SLE accompanied by lupus nephritis, joint pain, and clinical manifestations of oral ulcers had relatively low secretion of sPD-L2. In addition, this secretion level was significantly and positively correlated with complement components 3 and 4 (C3/C4). These results suggest that PD-L2 may be a promising biomarker associated with the pathogenesis of SLE.

Soluble immune checkpoint-related proteins as predictors of tumor recurrence, survival, and T cell phenotypes in clear cell renal cell carcinoma patients

Background

Immune checkpoint inhibitors have achieved unprecedented success in cancer immunotherapy. With the exception of a few candidate biomarkers, the prognostic role of soluble immune checkpoint-related proteins in clear cell renal cell cancer (ccRCC) patients is largely uninvestigated.

Methods

We profiled the circulating levels of 14 immune checkpoint-related proteins panel (BTLA, GITR, HVEM, IDO, LAG-3, PD-1, PD-L1, PD-L2, Tim-3, CD28, CD80, CD137, CD27 and CTLA-4) and their associations with the risk of recurrence and death in 182 ccRCC patients using a multiplex Luminex assay. Gene expression in tumors from a subset of participating patients (n = 47) and another 533 primary ccRCC from TCGA were analyzed to elucidate potential mechanisms. Our primary endpoint is overall survival; secondary endpoint is recurrence-free survival. Multivariate Cox proportional hazard model, unconditional logistic regression model, and Kaplan-Meier analysis were applied in the study.

Results

sTIM3 and sLAG3 were significantly associated with advanced (stage III) disease (P < 0.05). sPD-L2 was the strongest predictor of recurrence (HR 2.51, 95%CI 1.46–4.34, P = 9.33E-04), whereas high sBTLA and sTIM3 was associated with decreased survival (HR 6.02, 95%CI 2.0–18.1, P = 1.39E-03 and HR 3.12, 95%CI 1.44–6.75, P = 3.94E-03, respectively). Risk scores based on sTIM3 and sBTLA indicated that the soluble immune checkpoint-related proteins jointly predicted recurrence and death risks of ccRCC (P = 0.01 and 4.44E-04, respectively). Moreover, sLAG3 and sCD28 were found negatively correlated with cytolytic activity of T cells in tumors (rho = −0.31 and − 0.33, respectively).

Conclusions

Our study provides evidence that soluble immune checkpoint-related proteins may associate with advanced disease, recurrence and survival in ccRCC patients, which highlights the prognostic values of soluble immune checkpoint-related proteins. Future independent validation in prospective studies is warranted.

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.

Targeting Costimulatory Pathways in Systemic Sclerosis

Systemic sclerosis (SSc) is an autoimmune T-cell disease that is characterized by pathological fibrosis of the skin and internal organs. SSc is considered a prototype condition for studying the links between autoimmunity and fibrosis. Costimulatory pathways such as CD28/CTLA-4, ICOS-B7RP1, CD70-CD27, CD40-CD154, or OX40-OX40L play an essential role in the modulation of T-cell and inflammatory immune responses. A growing body of evidence suggests that T-cell costimulation signals might be implicated in the pathogenesis of SSc. CD28, CTLA-4, ICOS, and OX40L are overexpressed in patients with SSc, particularly in patients with cutaneous diffuse forms. In pre-clinical models of SSc, T-cell costimulation blockade with abatacept (CTLA-4-Ig) prevented and induced the regression of inflammation-driven dermal fibrosis, improved digestive involvement, prevented lung fibrosis, and attenuated pulmonary hypertension in complementary models of SSc. Likewise, potent anti-fibrotic effects were seen with the blockade of OX40L by reducing the infiltration of inflammatory cells into lesional tissues leading to decreased fibroblast activation. Concerning clinical effects, a preliminary observational study suggested some effectiveness of abatacept on inflammatory joint involvement, whereas clinical improvement of skin fibrosis was observed in a small placebo-controlled randomized trial. Currently there is one ongoing phase II clinical trial assessing the efficacy of abatacept in SSc (ASSET trial, NCT02161406). Overall, given the lack of available effective agents and the known toxic effects of immunosuppressive agents approved for use in SSc, costimulatory pathways offer the advantage of a targeted approach to costimulatory signals and potentially a better safety profile.

Association of CD28 and CTLA4 haplotypes with susceptibility to primary Sjögren's syndrome in Mexican population

BACKGROUND

Primary Sjögren's syndrome (pSS) is an autoimmune disease characterized by destruction of exocrine glands as a result of T and B cells infiltrated in glandular tissue. CD28 and CTLA-4 play a crucial role in T cell activation and inhibition. The aim of this study was to associate CD28 and CTLA4 haplotypes with susceptibility to pSS in patients from western Mexico.

METHODS

Polymerase chain reaction and restriction fragment length polymorphism were performed to identify CD28 and CTLA4 genotypes in 111 patients with pSS and 138 control subjects (CS). Haplotype analysis was carried out by SHEsis program. Soluble serum levels of CD28 (sCD28) and CTLA-4 (sCTLA-4) were quantified by ELISA kit.

RESULTS

The CD28 GC haplotype was associated with low risk to pSS (2.5-folds, P < 0.001). CTLA4 CAG and CGA were identified as genetic risk factor (P < 0.001;OR = 3.82[CI95%:2.022-7.296] and P < 0.001; OR = 11.38[CI95%:3.282-37.69] respectively). No difference in sCD28 and sCTLA-4 were found between patients and CS. However, pSS patients carriers of CD28 IVS3 + 17TC genotype showed high sCD28 (P = 0.039 vs TT carriers in CS). In regard to sCTLA-4, patient who carry CTLA4-319C>T, +49 A>G, and +6230 G>A, or their haplotypes did not show any difference.

CONCLUSION

Our findings suggest that CD28 GC, CTLA4 CAG, and CGA haplotypes are associated with susceptibility to pSS in patients from western Mexico. It seems that genetic control of CD28 and CTLA4 as well as local immune response in glandular tissue may regulate the impact of the gene expression in pSS. It is necessary to confirm this hypothesis in an integrative study.

SheddomeDB: the ectodomain shedding database for membrane-bound shed markers

BACKGROUND

A number of membrane-anchored proteins are known to be released from cell surface via ectodomain shedding. The cleavage and release of membrane proteins has been shown to modulate various cellular processes and disease pathologies. Numerous studies revealed that cell membrane molecules of diverse functional groups are subjected to proteolytic cleavage, and the released soluble form of proteins may modulate various signaling processes. Therefore, in addition to the secreted protein markers that undergo secretion through the secretory pathway, the shed membrane proteins may comprise an additional resource of noninvasive and accessible biomarkers. In this context, identifying the membrane-bound proteins that will be shed has become important in the discovery of clinically noninvasive biomarkers. Nevertheless, a data repository for biological and clinical researchers to review the shedding information, which is experimentally validated, for membrane-bound protein shed markers is still lacking.

RESULTS

In this study, the database SheddomeDB was developed to integrate publicly available data of the shed membrane proteins. A comprehensive literature survey was performed to collect the membrane proteins that were verified to be cleaved or released in the supernatant by immunological-based validation experiments. From 436 studies on shedding, 401 validated shed membrane proteins were included, among which 199 shed membrane proteins have not been annotated or validated yet by existing cleavage databases. SheddomeDB attempted to provide a comprehensive shedding report, including the regulation of shedding machinery and the related function or diseases involved in the shedding events. In addition, our published tool ShedP was embedded into SheddomeDB to support researchers for predicting the shedding event on unknown or unrecorded membrane proteins.

CONCLUSIONS

To the best of our knowledge, SheddomeDB is the first database for the identification of experimentally validated shed membrane proteins and currently may provide the most number of membrane proteins for reviewing the shedding information. The database included membrane-bound shed markers associated with numerous cellular processes and diseases, and some of these markers are potential novel markers because they are not annotated or validated yet in other databases. SheddomeDB may provide a useful resource for discovering membrane-bound shed markers. The interactive web of SheddomeDB is publicly available at http://bal.ym.edu.tw/SheddomeDB/ .

New Murine Model of Early Onset Autoimmune Thyroid Disease/Hypothyroidism and Autoimmune Exocrinopathy of the Salivary Gland

Sixty to seventy percent of IFN-γ(-/-) NOD.H-2h4 mice given sodium iodide (NaI)-supplemented water develop a slow onset autoimmune thyroid disease, characterized by thyrocyte epithelial cell (TEC) hyperplasia and proliferation (H/P). TEC H/P develops much earlier in CD28(-/-) mice and nearly 100% (both sexes) have severe TEC H/P at 4 mo of age. Without NaI supplementation, 50% of 5- to 6-mo-old CD28(-/-)IFN-γ(-/-) mice develop severe TEC H/P, and 2-3 wk of NaI is sufficient for optimal development of severe TEC H/P. Mice with severe TEC H/P are hypothyroid, and normalization of serum thyroxine levels does not reduce TEC H/P. Activated CD4(+) T cells are sufficient to transfer TEC H/P to SCID recipients. Thyroids of mice with TEC H/P have infiltrating T cells and expanded numbers of proliferating thyrocytes that highly express CD40. CD40 facilitates, but is not required for, development of severe TEC H/P, as CD40(-/-)IFN-γ(-/-)CD28(-/-) mice develop severe TEC H/P. Accelerated development of TEC H/P in IFN-γ(-/-)CD28(-/-) mice is a result of reduced regulatory T cell (Treg) numbers, as CD28(-/-) mice have significantly fewer Tregs, and transfer of CD28(+) Tregs inhibits TEC H/P. Essentially all female IFN-γ(-/-)CD28(-/-) NOD.H-2h4 mice have substantial lymphocytic infiltration of salivary glands and reduced salivary flow by 6 mo of age, thereby providing an excellent new model of autoimmune exocrinopathy of the salivary gland. This is one of very few models where autoimmune thyroid disease and hypothyroidism develop in most mice by 4 mo of age. This model will be useful for studying the effects of hypothyroidism on multiple organ systems.

Immune checkpoint receptors in regulating immune reactivity in rheumatic disease

Immune checkpoint regulators are critical modulators of the immune system, allowing the initiation of a productive immune response and preventing the onset of autoimmunity. Co-inhibitory and co-stimulatory immune checkpoint receptors are required for full T-cell activation and effector functions such as the production of cytokines. In autoimmune rheumatic diseases, impaired tolerance leads to the development of diseases such as rheumatoid arthritis, systemic lupus erythematosus, and Sjogren’s syndrome. Targeting the pathways of the inhibitory immune checkpoint molecules CD152 (cytotoxic T lymphocyte antigen-4) and CD279 (programmed death-1) in cancer shows robust anti-tumor responses and tumor regression. This observation suggests that, in autoimmune diseases, the converse strategy of engaging these molecules may alleviate inflammation owing to the success of abatacept (CD152-Ig) in rheumatoid arthritis patients. We review the preclinical and clinical developments in targeting immune checkpoint regulators in rheumatic disease.

Development and validation of an LC-MS/MS assay for the quantitation of a PEGylated anti-CD28 domain antibody in human serum: overcoming interference from antidrug antibodies and soluble target

AIM

To support drug development of a PEGylated anti-CD28 domain antibody, a sensitive and robust LC-MS/MS assay was developed for the first in-human multiple ascending dose study.

MATERIALS & METHODS

The procedure consists of a protein precipitation with acidified acetonitrile, followed by trypsin digestion of the supernatant. A surrogate peptide from the complementarity determining region was quantified with an LC-MS/MS assay using a stable isotope-labeled internal standard with flanking amino acids. An acid dissociation step was found to be essential to achieve full analyte recovery in the presence of antidrug antibodies and soluble target CD28.

RESULTS & CONCLUSION

The fully validated LC-MS/MS assay demonstrates good accuracy (% deviation ≤6.3) and precision (%CV ≤5.2) with an lower limit of quantitation of 10 ng/ml.

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.

Potentiating functional antigen-specific CD8⁺ T cell immunity by a novel PD1 isoform-based fusion DNA vaccine

Understanding and identifying new ways of mounting an effective CD8⁺ T cell immune response is important for eliminating infectious pathogens. Although upregulated programmed death-1 (PD1) in chronic infections (such as HIV-1 and tuberculosis) impedes T cell responses, blocking this PD1/PD-L pathway could functionally rescue the "exhausted" T cells. However, there exists a number of PD1 spliced variants with unknown biological function. Here, we identified a new isoform of human PD1 (Δ42PD1) that contains a 42-nucleotide in-frame deletion located at exon 2 domain found expressed in peripheral blood mononuclear cells (PBMCs). Δ42PD1 appears to function distinctly from PD1, as it does not engage PD-L1/PD-L2 but its recombinant form could induce proinflammatory cytokines. We utilized Δ42PD1 as an intramolecular adjuvant to develop a fusion DNA vaccine with HIV-1 Gag p24 antigen to immunize mice, which elicited a significantly enhanced level of anti-p24 IgG1/IgG2a antibody titers, and important p24-specific and tetramer⁺CD8⁺ T cells responses that lasted for ≥7.5 months. Furthermore, p24-specific CD8⁺ T cells remain functionally improved in proliferative and cytolytic capacities. Importantly, the enhanced antigen-specific immunity protected mice against pathogenic viral challenge and tumor growth. Thus, this newly identified PD1 variant (Δ42PD1) amplifies the generation of antigen-specific CD8⁺ T cell immunity when used in a DNA vaccine.

The CD28/B7 pathway: a novel regulator of plasma cell function

The CD28/B7 pathway is pivotal for the activation, optimal function, and regulation of T cell function. While the CD28 receptor and its ligands B7.1/B7.2 are also expressed on plasma cells, little is known of the role of the CD28/B7 pathway in plasma cell function. In this chapter we discuss the recent studies that have examined the role of CD28 expression on plasma cell function. Both stimulatory and inhibitory effects of CD28 on plasma cells have been reported. Based on our findings we propose that under homeostatic conditions the CD28/B7 interaction mediates regulation of plasma cell function whereas during inflammation this pathway can be perturbed to ramp up Ab production from existing plasma cells.

Expression profiles of Th17 pathway related genes in human systemic lupus erythematosus

Recently, evidence is emerging that inappropriate regulation of type 17 T helper cells (Th17) plays a fundamental role in the development of many autoimmune diseases including systemic lupus erythematosus (SLE). However, the role of Th17-related cytokines in SLE remains elusive. To further investigate the role and imbalance of Th17-related cytokines in the pathogenesis of SLE. A Quantitative RT-PCR Array (Human Th17 for Autoimmunity & Inflammation PCR Array) analyses were performed to study Th17-related genes expression in peripheral white blood cells of 25 new-onset patients with SLE and 15 healthy subjects. When gene expression for SLE patients was compared to the mean of normal controls, among the 84 target genes related to Th17 pathway, 7 (CXCL1, ICAM1, IL10, IL5, IL8, ISG20, JAK2,) were upregulated and 6 (CD28, CD40LG, S1PR1, IL17RE, IL23R, RORC) downregulated. However, comparisons of mRNA expression of Th17 related cytokines between lupus nephritis (LN) patients and SLE patients without nephritis (SLE non LN) showed no significant difference. In conclusion, SLE patients and normal controls showed different expression of a few genes in Th17 pathway, indicating that the pathway may be involved in the pathogenesis of SLE.

CD28-B7 interaction modulates short- and long-lived plasma cell function

The interaction of CD28, which is constitutively expressed on T cells, with B7.1/B7.2 expressed on APCs is critical for T cell activation. CD28 is also expressed on murine and human plasma cells but its function on these cells remains unclear. There are two types of plasma cells: short-lived ones that appear in the secondary lymphoid tissue shortly after Ag exposure, and long-lived plasma cells that mainly reside in the bone marrow. We demonstrate that CD28-deficient murine short- and long-lived plasma cells produce significantly higher levels of Abs than do their wild-type counterparts. This was owing to both increased frequencies of plasma cells as well as increased Ab production per plasma cell. Plasma cells also express the ligand for CD28, B7.1, and B7.2. Surprisingly, deficiency of B7.1 and B7.2 in B cells also led to higher Ab levels, analogous to Cd28(-/-) plasma cells. Collectively, our results suggest that the CD28-B7 interaction operates as a key modulator of plasma cell function.

Increased CD28 serum levels are not associated with specific clinical activity in systemic lupus erythematosus

CD28 is one of the main activator receptors involved in systemic lupus erythematosus (SLE) pathogenesis, and its expression and serum levels are significantly higher in patients with SLE and other autoimmune diseases than in healthy controls (HC). However, it is unknown whether this increase is associated with specific organ damage. Therefore, our objective was to measure the CD28 levels in serum from SLE and HC groups to confirm the CD28 serum levels increase, as reported previously, and to determine whether this increase was associated with specific organ activity and the SLE Disease Activity Index (SLEDAI). Forty SLE patients and 40 matched HC were included, and the age, disease duration, SLEDAI and Mexican SLEDAI were recorded for the SLE group. CD28 serum levels were measured by ELISA. There was a statistically significant increase in the CD28 serum levels of SLE patients compared to controls (p = 0.039); however, we did not find any significant correlation with disease activity indices or organ involvement, although we found a significant but low correlation with C3. Our results and a review of the literature suggest that the increase in CD28 serum levels may be the result of CD28 gene overexpression, which could be related to the decrease in CD28+ T cells, T-cell hyporesponsiveness and immune impairment that occurs in SLE.

Plasma sCD28, sCTLA-4 levels in neuromyelitis optica and multiple sclerosis during relapse

BACKGROUND

Soluble forms of CD28 (sCD28) and CTLA-4 (sCTLA-4) were associated with many autoimmune diseases like Sjögren's syndrome, systemic lupus erythematosus, asthma, and autoimmune myasthenia gravis. However, sCD28 and sCTLA-4 in neuromyelitis optica (NMO) and multiple sclerosis (MS) patients were less studied.

OBJECTIVE

To measure the plasma sCD28, sCTLA-4 in NMO and MS patients, and investigate whether sCD28 and sCTLA-4 possible use as sensitive biomarkers for diseases activity.

METHODS

Plasma concentrations of sCD28, sCTLA-4 were measured by an enzyme-linked immunosorbent assay (ELISA) in NMO (n=22), MS (n=21) patients and controls (n=18).

RESULTS

The concentration of sCD28 levels were higher in the inflammatory demyelinating diseases cohort compared with the controls (NMO, p=0.034; MS, p=0.026) and the levels of sCD28 were slightly higher in NMO compared with MS. The sCTLA-4 levels were lower in the MS subgroup compared with the controls (p=0.032). Both sCD28 and sCTLA-4 did not show any correlation with EDSS score in NMO and MS patients.

CONCLUSIONS

Our study revealed for the first time that the levels of increased plasma sCD28 and decreased plasma sCTLA-4 in NMO and MS patients, but had little correlation with clinical presentations.

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.

CD28 proximal promoter polymorphisms in systemic lupus erythematosus susceptibility

CD28 expression and serum levels are significantly increased in patients with SLE than in healthy controls (HC). Until now, there are no studies of proximal promoter polymorphisms of CD28 gene in SLE. Therefore, our objective was to investigate the polymorphisms present in the proximal promoter of CD28 in a group of SLE and HC and to associate the polymorphisms present with the CD28 serum levels of 40 patients and 40 controls. One hundred and seven patients as well as 108 controls matched by age range and genders were included. The 11 ACR criteria were analyzed on the clinical files, and the proximal promoter region of CD28 gene was analyzed by direct sequencing of a 489-basepair fragment. C28 serum levels (sCD28) were measured by ELISA technique in 40 patients and 40 controls. Only two of the eight reported polymorphisms were found, and they correspond to rs35593994 (-372 A/G) and rs56156157 (-145 -/C). The first had a prevalence of 41 and 36% in patients and controls respectively and the second of 1.4% in both groups. None of these polymorphisms were associated with SLE, and the polymorphism -372 A/G was not associated with the clinical features of disease. Likewise, the association with the sCD28 and the genotypes of -372 A/G polymorphism was not significant. The polymorphisms of the proximal promoter of CD28 are not associated with SLE, and the polymorphism -372 A/G is not associated with the diagnostic criteria of SLE or the sCD28.

Identification of a soluble form of B7-H1 that retains immunosuppressive activity and is associated with aggressive renal cell carcinoma

PURPOSE

Release of inhibitory coregulatory proteins into the circulation may represent one mechanism by which tumors thwart immune responses. Our objective was to determine whether soluble B7-H1 (sB7-H1) levels in patients with clear cell renal cell carcinoma (ccRCC) are associated with pathologic features and patient outcome.

EXPERIMENTAL DESIGN

We developed an ELISA for quantification of sB7-H1 in biological fluids. Biochemical confirmation of the measured analyte as sB7-H1 was done by protein microsequencing using supernates from tumor cell lines. Biological activity of sB7-H1 was assessed in vitro utilizing T-cell apoptosis assays. We tested sB7-H1 levels in the sera from 172 ccRCC patients and correlated sB7-H1 levels with pathologic features and patient outcome.

RESULTS

sB7-H1 was detected in the cell supernatants of some B7-H1-positive tumor cell lines. Protein sequencing established that the measured sB7-H1 retained its receptor-binding domain and could deliver proapoptotic signals to T cells. Higher preoperative sB7-H1 levels were associated with larger tumors (P < 0.001), tumors of advanced stage (P = 0.017) and grade (P = 0.044), and tumors with necrosis (P = 0.003). A doubling of sB7-H1 levels was associated with a 41% increased risk of death (P = 0.010).

CONCLUSION

Our observations suggest that sB7-H1 may be detected in the sera of ccRCC patients and that sB7-H1 may systemically impair host immunity, thereby fostering cancer progression and subsequent poor clinical outcome.

MicroRNA array analysis of microRNAs related to systemic scleroderma

MicroRNAs are short, 18- to 25-nt sequences of noncoding, single-stranded RNA that function as regulatory molecules and participate in a series of vital processes including early development, cell proliferation, cell differentiation, apoptosis, substance metabolism and the pathogenesis of human diseases. This study compared the microRNA profiles of patients with systemic scleroderma (SSc) and healthy control individuals to investigate the pathogenesis of SSc. Skin tissue was isolated from three patients with SSc and three healthy controls. miRNA microarray chip analysis identified 24 miRNAs that were differentially expressed in patients with SSc and 6 microRNAs that may be correlated with the pathogenesis of SSc. The results of the microarray analysis were confirmed using real-time PCR. This work suggests that miRNAs may be potential diagnosis biomarkers and are likely to be involved in the pathogenesis of SSc.

Circulating soluble CTLA-4 is related to inflammatory markers in the 70 year old population

OBJECTIVE

Measurement of inflammatory mediators is an important tool to assess inflammation. We have, therefore, conducted a survey within the Prospective Investigation of the Vasculature in Uppsala Seniors (PIVUS) study to evaluate the inter-relationship between soluble CTLA-4 (sCTLA-4) and other inflammatory markers.

MATERIALS AND METHODS

This is a population-based study, designed to quantify the circulating serum levels of sCTLA-4 and other inflammatory markers such as CRP and pro-inflammatory cytokines and chemokines by in-house ELISA, Immuno-turbidimetry and multiplex ELISA, respectively. A total of 1016 Swedish Caucasians aged 70 years old were recruited. The statistical analysis was performed by ANOVA.

RESULTS

The levels of sCTLA-4 were directly related to the levels of pro-inflammatory cytokines such as IL-6, IL-1alpha, IL-1beta, TNF-alpha, IFN-gamma and chemokines such as IL-8. However, the levels of sCTLA-4 were inversely related to the levels of MCP-1. Also, we could not demonstrate any relation between the levels of sCTLA-4 and CRP or soluble adhesion molecules.

CONCLUSIONS

Circulating sCTLA-4 could be used as a biomarker for inflammation, potentially reflecting dysregulated T lymphocytes.

The soluble forms of CD28, CD86 and CTLA-4 constitute possible immunological markers in patients with abdominal aortic aneurysm

OBJECTIVE

The T cell co-stimulatory factors CD28 and CTLA-4 and their ligands CD80 and CD86 occur as receptors on T cells and antigen-presenting cells and also in soluble forms in the circulation. We determined the levels of soluble co-stimulatory molecules in patients with abdominal aortic aneurysm (AAA) and normal individuals. We further correlated these soluble co-stimulatory molecules to other clinical parameters of importance such as age of the patient, presence of hypertension, size of the aneurysm and levels of matrix metalloproteinases-9 and C-reactive protein.

DESIGN, SETTING, SUBJECTS

This case-control study was designed to quantify the circulating levels of soluble co-stimulatory molecules by an in-house enzyme linked immunosorbent assay. A total of 314 subjects participated in the study including 100 patients and 214 normal controls. The statistical analysis was performed by Mann-Whitney test and Spearman's correlation rank test.

RESULTS

Our results show increased plasma levels of sCD28, sCD86 (P = 0.0001) and decreased plasma levels of sCTLA-4 (P = 0.0018) in the patients compared with normal individuals. The levels of these factors were not related to the age of the patient, size of aneurysm or levels of C-reactive protein in plasma. There was, however, a significant inverse relationship between the concentrations of sCTLA-4 and sCD80 with matrix metalloproteinase-9.

CONCLUSIONS

We suggest that soluble co-stimulatory molecules serve as biomarkers for the estimation of immune activation in AAA patients.

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.

Immunopathogenesis of primary Sjögren's syndrome: implications for disease management and therapy

PURPOSE OF REVIEW

Recent studies have broadened our understanding of the etiopathogenesis and immunopathology of primary Sjögren's syndrome. This review highlights recent advances in understanding the underlying mechanisms of the disease as well as their implications for clinical handling and therapeutic options.

RECENT FINDINGS

It becomes increasingly apparent that certain disturbances of the immune system (i.e. B-cell hyperreactivity and enhanced levels of B-cell-activating factor/B-lymphocyte stimulator) play a central role in this entity. Whether this is a primary abnormality or the result of predisposing factors or infectious, e.g. viral, agents remains uncertain. New insights into the pathogenesis also provide candidates for better diagnosis and classification of disease severity, such as flow cytometric analysis, measurement of soluble cell surface molecules, autoantibodies, cytokines, and ligands (B-cell-activating factor/B-lymphocyte stimulator). Whether B-cell-directed therapies (i.e. blocking B-cell-activating factor/B-lymphocyte stimulator, anti-CD20 therapy) will have an impact on primary Sjögren's syndrome needs to be shown in clinical trials. Alternative therapeutic approaches such as organ-targeted gene transfer are in development but must be carefully evaluated for safety and efficacy in preclinical models that resemble human primary Sjögren's syndrome.

SUMMARY

The pathogenesis of primary Sjögren's syndrome is complex and the factors initiating and driving autoimmunity in this entity are largely unknown. Recent studies provide new insights into potential pathogenetic mechanisms of the disease and, thereby, the chance for improved strategies in disease management and therapy.

Effect of CD4+ CD25+ regulatory T-cells on CD8 T-cell function in patients with autoimmune hepatitis

BACKGROUND AND AIMS

CD4 T lymphocytes constitutively expressing the IL-2-receptor alpha-chain (CD25) (T-regs) are central to self-tolerance maintenance, preventing the proliferation and effector function of autoreactive T-cells. In autoimmune hepatitis T-regs are defective in number but maintain the ability to suppress IFNgamma production by CD4+CD25- T-cells. We have studied the ability of CD4+CD25+ (T-regs) to regulate proliferation and cytokine production by CD8 T-cells in patients with autoimmune hepatitis at diagnosis and during remission.

METHODS

Twenty-five patients were studied. T-regs were purified from PBMCs by CD4 negative selection followed by CD25 positive selection, using immunomagnetic beads. The ability of T-regs to suppress CD8 T-cell proliferation was assessed by 3H-thymidine incorporation; their ability to regulate cytokine production by intracellular cytokine staining.

RESULTS

We found that T-regs are unable to regulate CD8 T-cell proliferation and cytokine production in patients studied at diagnosis, while they suppress CD8 T-cell proliferation and induce an elevation of IL-4 producing CD8 T-cells in patients during drug-induced remission.

CONCLUSION

Inability of T-regs to regulate CD8 T-cell function at diagnosis may contribute to the initiation of autoimmune liver damage. The ability of T-regs to regulate CD8 proliferation and IL-4 production during drug-induced remission suggests a role for immunosuppressive treatment at reconstituting T-regs function.

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

The co-stimulatory interactions of the B7 family molecules CD80 and CD86 on antigen-presenting cells, together with their T cell counter receptors CD28 and cytotoxic T lymphocyte-associated antigen-4 (CTLA-4), modulate T lymphocyte-mediated immune responses in a reciprocal manner. To investigate whether there is altered expression and the clinical significance of soluble co-stimulatory molecules in asthmatic patients, plasma concentrations of sCTLA-4, sCD28, sCD80 and sCD86 in 51 adult allergic asthmatic adults with or without steroid treatment, and 35 sex- and age-matched control subjects were measured by enzyme-linked immunosorbent assay (ELISA). Cell surface expression of CTLA-4 and CD28 on peripheral blood mononuclear cells (PBMC) were analysed by flow cytometry. Results showed that the plasma sCTLA-4 concentration was significantly higher in all asthmatic patients while sCD28 and sCD86 concentrations were significantly higher in steroid and non-steroid treated asthmatic patients, respectively, compared with control subjects (all P < 0.01). Significantly increased cell surface expression of CD28 but not CTLA-4 on PBMC was found in asthmatic patients compared with controls (P < 0.05). The plasma concentration and cell surface expression of CTLA-4 were found to exhibit positive and significant correlations with those of CD28 (both P < 0.05). Serum total IgE concentration correlated positively and significantly with sCTLA-4 and sCD28 concentrations in allergic asthmatic patients (both P < 0.05). The increased expression of these soluble co-stimulatory molecules may reflect the dysregulation of T cell activation, thereby contributing to the immunopathogenesis of allergic asthma.

Aberrant production of soluble costimulatory molecules CTLA-4, CD28, CD80 and CD86 in patients with systemic lupus erythematosus

OBJECTIVE

The costimulatory interactions of the B7 family molecules CD80 and CD86 on antigen-presenting cells with their T-cell counter-receptors CD28 and CTLA-4 modulate T lymphocyte-mediated immune responses in a reciprocal manner. We investigated the possible aberrant production of soluble (s) forms of the T-cell costimulatory molecules CD80, CD86, CD28 and CTLA-4 in plasma of patients with systemic lupus erythematosus (SLE), an autoimmune disease arising from T-lymphocyte dysregulation.

METHODS

Plasma concentration and ex vivo production of soluble costimulatory molecules of 79 SLE patients with or without active disease and 40 sex- and age-matched healthy subjects were measured by enzyme-linked immunosorbent assay.

RESULTS

Plasma sCTLA-4, sCD28, sCD80 and sCD86 concentrations of all SLE patients were significantly higher than concentrations in control subjects (all P<0.01). These increases were observed even in patients with inactive disease [SLE Disease Activity Index (SLEDAI) <3]. Plasma sCTLA-4 concentration in all SLE patients correlated significantly with SLEDAI score (r = 0.228, P = 0.043). Upon mitogen treatment 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 smaller in SLE patients with active disease than in healthy subjects (P<0.01, P<0.05 and P<0.0001, respectively).

CONCLUSION

The aberrant production of soluble T-cell costimulatory molecules is important in the immunopathogenesis of SLE, which occurs by the dysregulation of T-lymphocyte costimulation. Plasma sCTLA concentration could potentially serve as a surrogate marker of SLE disease activity.

Elevation of plasma soluble T cell costimulatory molecules CTLA-4, CD28 and CD80 in children with allergic asthma

BACKGROUND

The surface expression of T cell costimulatory molecules CTLA-4 and CD28 and their counter-ligands, B7 molecules (CD80, CD86), is differentially induced for T cell activation and expansion in allergic asthma. However, the role of their soluble forms in plasma has not yet been elucidated. In this study, we investigated whether expression is altered and whether soluble costimulatory molecules are clinically relevant in asthmatic patients.

METHODS

Plasma concentrations of soluble CTLA-4 (sCTLA-4), CD28, CD80 and CD86 in 51 children with chronic allergic asthma with or without inhaled corticosteroid treatment, and 22 sex- and age-matched control subjects were measured by enzyme-linked immunosorbent assay. Plasma total IgE concentration was measured using a microparticle immunoassay.

RESULTS

Asthmatic patients had higher logarithmic plasma total IgE concentration (IgE(log)) than healthy subjects (p < 0.0001). In non-steroid-treated patients, plasma sCTLA-4, sCD28 and sCD80 but not sCD86 concentrations were significantly higher than those of control subjects (all p < 0.05). Plasma sCD80 and sCD86 but not sCTLA-4 and sCD28 concentrations correlated significantly with IgE(log) of all subjects (p < 0.05). There were also significant positive correlations between sCTLA-4 and sCD28 (p = 0.0007), and between sCD80 and sCD86 in all asthmatic patients (p = 0.001).

CONCLUSIONS

Plasma sCTLA-4, sCD28 and sCD80 concentrations are elevated in allergic asthma. The increased expression of these soluble proteins may reflect the dysregulation of T cell activation, contributing to the immunopathogenesis of allergic asthma.