On the role of sIL-2R measurements in rheumatoid arthritis and cancers

Evaluation serum soluble interleukin 2 receptor with diagnosis and prognosis in canine solid tumour: 34 cases

BACKGROUND/AIM

The soluble interleukin-2 receptor (sIL-2R) serve as a valuable biomarker for tumors in human patients, as its levels increase during the activation of T lymphocytes in clinical states such as inflammation, infection, and tumor. This study aimed to demonstrate that sIL-2R levels can be also elevated in dogs with tumors and evaluate its applicability as a diagnostic and prognostic factor in canine cancer patients.

PATIENTS AND METHODS

Serum was collected from 6 healthy dogs and 34 dogs with solid tumors. The concentration of sIL-2R was measured using a commercial enzyme-linked immunosorbent assay kit.

RESULTS

The median sIL-2R concentration was significantly higher in dogs with solid masses than in healthy dogs (117.3 vs 68.33 pg/ml, p = 0.016). The highest median sIL-2R concentration was found in dogs with malignant tumors, followed by those with benign tumors, and healthy dogs (119.6 vs 93.74 vs 68.33 pg/ml, respectively). In dogs with malignant tumors, the mortality rate was significantly higher in the group with high sIL-2R levels than in the group with low sIL-2R levels. Dogs with solid tumors, particularly those with malignant tumors, had higher concentrations of sIL-2R than healthy dogs. Among dogs with malignant tumors, a correlation between sIL-2R concentration and mortality rate was confirmed.

CONCLUSION

Serum sIL-2R levels may be used to detect malignant tumors and serve as a prognostic factor in dogs with malignant tumors.

Diagnostic value of soluble Interleukin-2 receptor in patients suffering neurosarcoidosis: A systematic review

Background

Neurosarcoidosis is an inflammatory granulomatous disease. Up to 25% of occult sarcoidosis affecting the nervous system are only detected by autopsy. In addition, in recent years the suspicion arose that the soluble Interleukin-2 Receptor (sIL-2R) might be useful in differentiating between neurosarcoidosis and neurosarcoidosis-like diseases such as neurotuberculosis, multiple sclerosis, or cerebral lymphoma.

Objectives

Therefore, we aimed to systematically review randomized controlled trials (RCT), observational studies, and case-control studies evaluating sIL-2R levels in neurosarcoidosis patients.

Design

For this systematic review, a comprehensive literature search of electronic databases including EMBASE, The Web Of Science, The Cochrane Library, MEDLINE, and Google Scholar was conducted. The search was limited to the English language and publication date up to January 08th, 2024.

Data Sources and Methods

As part of the search strategy conducted, 6 articles met the inclusion criteria. Two independent reviewers extracted the relevant data from each article. In addition, 2 independent reviewers assessed the quality of each study using the Newcastle-Ottawa Scale (NOS).

Results

We included 6 studies comprising 98 patients suffering from neurosarcoidosis, 525 non-sarcoidosis patients, and 118 healthy controls. Included studies were published between 2010 and 2023. Cerebrospinal fluid (CSF) sIL-2R levels differed significantly between neurosarcoidosis patients and multiple sclerosis, vasculitis, and healthy controls whereas serum sIL-2R levels did not reveal sufficient discriminative power. sIL-2R index was able to discriminate neurosarcoidosis from neurotuberculosis, bacterial/viral meningitis, and healthy controls.

Conclusions

In this systematic review, we found indications that sIL-2R may be a useful biomarker for the diagnosis of neurosarcoidosis. To determine an additional diagnostic value of sIL-2R, large prospective studies are needed that not only examine absolute sIL-2R levels in serum or CSF but also the dynamic changes as well as the implications of renal function on sIL-2R levels.

Serum Soluble IL-2 Receptors Are Elevated in Febrile Illnesses and Useful for Differentiating Clinically Similar Malignant Lymphomas from Kikuchi Disease: A Cross-Sectional Study

Background: The use of serum soluble interleukin 2 receptor (sIL-2R) for the diagnosis of febrile illnesses has not been examined. In this study, febrile patients were classified according to etiology and disease, and serum sIL-2R levels were evaluated. We determined whether serum sIL-2R is a useful marker for differentiating between malignant lymphoma (ML) and non-ML patients and between patients with ML and Kikuchi disease, which present similar clinical manifestations. Methods: This study was a cross-sectional study and included 344 patients with uncomplicated hemophagocytic syndrome, who had a fever of 38 °C or higher within 1 week of admission to our institution. Patient serum sIL-2R was measured, and the serum sIL-2R values are shown as median and IQR. Results: Serum sIL-2R increased above the upper reference limit in all disease groups with fever. The serum sIL-2R level in ML patients (n = 13) was 4760 (2120-6730) U/mL and significantly higher (p < 0.001) than the level of 998 (640-1625) U/mL in non-ML patients (n = 331). The serum sIL-2R level in ML patients (n = 13) was also significantly higher (p < 0.001) compared with that in patients with Kikuchi disease (n = 20; 705 (538-1091) U/mL). Conclusions: Serum sIL-2R tends to exceed the upper reference limit in patients with febrile illnesses. We conclude that the measurement of serum sIL-2R is useful for differentiating ML from non-ML and ML from Kikuchi disease.

Inflammation and Neurodegeneration in Glaucoma: Isolated Eye Disease or a Part of a Systemic Disorder? - Serum Proteomic Analysis

Introduction

Glaucoma is the most common optic neuropathy and the leading cause of irreversible blindness worldwide, which affects 3.54% of the population aged 40-80 years. Despite numerous published studies, some aspects of glaucoma pathogenesis, serum biomarkers, and their potential link with other diseases remain unclear. Recent articles have proposed that autoimmune, oxidative stress and inflammation may be involved in the pathogenesis of glaucoma.

Methods

We investigated the serum expression of 92 inflammatory and neurotrophic factors in glaucoma patients. The study group consisted of 26 glaucoma patients and 192 healthy subjects based on digital fundography.

Results

Patients with glaucoma had significantly lower serum expression of IL-2Rβ, TWEAK, CX3CL1, CD6, CD5, LAP TGF-beta1, LIF-R, TRAIL, NT-3, and CCL23 and significantly higher expression of IL-22Rα1.

Conclusion

Our results indicate that patients with glaucoma tend to have lower levels of neuroprotective proteins and higher levels of neuroinflammatory proteins, similar to those observed in psychiatric, neurodegenerative and autoimmune diseases, indicating a potential link between these conditions and glaucoma pathogenesis.

Comprehensive immunoprofiling of neurodevelopmental disorders suggests three distinct classes based on increased neurogenesis, Th-1 polarization or IL-1 signaling

Neurodevelopmental disorders (NDDs) are a spectrum of conditions with commonalities as well as differences in terms of phenome, symptomatome, neuropathology, risk factors and underlying mechanisms. Immune dysregulation has surfaced as a major pathway in NDDs. However, it is not known if neurodevelopmental disorders share a common immunopathogenetic mechanism. In this study, we explored the possibility of a shared immune etiology in three early-onset NDDs, namely Autism Spectrum Disorder (ASD), Attention Deficit Hyperactivity Disorder (ADHD) and Intellectual Disability Disorder (IDD). A panel of 48 immune pathway-related markers was assayed in 135 children with NDDs, represented by 45 children with ASD, ADHD and IDD in each group, along with 35 typically developing children. The plasma levels of 48 immune markers were analyzed on the Multiplex Suspension Assay platform using Pro Human cytokine 48-plex kits. Based on the cytokine/chemokine/growth factor levels, different immune profiles were computed. The primary characteristics of NDDs are depletion of the compensatory immune-regulatory system (CIRS) (z composite of IL-4, IL-10, sIL-1RA, and sIL-2R), increased interleukin (IL)-1 signaling associated with elevated IL-1α and decreased IL-1-receptor antagonist levels, increased neurogenesis, M1/M2 macrophage polarization and increased IL-4 as well as C-C Motif Chemokine Ligand 2 (CCL2) levels. With a cross-validated sensitivity of 81.8% and specificity of 94.4%, these aberrations seem specific for NDDs. Many immunological abnormalities are shared by ASD, ADHD and IDD, which are distinguished by minor differences in IL-9, IL-17 and CCL12. In contrast, machine learning reveals that NDD group consists of three immunologically distinct clusters, with enhanced neurogenesis, Th-1 polarization, or IL-1 signaling as the defining features. NDD is characterized by immune abnormalities that have functional implications for neurogenesis, neurotoxicity, and neurodevelopment. Using machine learning, NDD patients could be classified into subgroups with qualitatively distinct immune disorders that may serve as novel drug targets for the treatment of NDDs.

Is there an association between serum soluble interleukin-2 receptor levels and syndrome severity in persistent Complex Regional Pain Syndrome?

OBJECTIVE

A potentially useful biomarker for Complex Regional Pain Syndrome (CRPS) is the serum soluble interleukin-2 receptor (sIL-2R) level, which is a marker for T-cell activation. Elevated serum sIL-2R levels have been described in CRPS patients compared to healthy controls. In T-cell mediated inflammatory diseases such as sarcoidosis and rheumatoid arthritis, the serum sIL-2R levels correlate with disease severity. In this study, we investigate whether an association exists between serum sIL-2R levels in CRPS patients and CRPS severity.

METHODS

A cross-sectional cohort study was conducted in a tertiary pain referral center in the Netherlands. Adult CRPS patients diagnosed by the IASP criteria were included between October 2018 until October 2022. The main study parameters were serum sIL-2R levels and the CRPS severity score.

RESULTS

Fifty-three CRPS patients were included with a mean syndrome duration of 84 months (Q3 - Q1:180 - 48). The majority had persistent CRPS with a syndrome duration >1 year (n = 52, 98%). The median pain Numerical Rating Score (NRS) was 7 (Q3 - Q1: 8 - 5) and the mean CRPS severity score was 11 (SD ± 2.3). The median serum sIL-2R level was 330 U/mL (Q3 - Q1:451 - 256). No statistically significant correlation was observed between serum sIL-2R levels and the CRPS severity score (rs = 0.15, P = .28).

CONCLUSIONS

Our findings suggest that serum sIL-2R levels cannot be used as a biomarker for syndrome severity in persistent CRPS (syndrome duration >1 year). Serial measurements of serum sIL-2R from early CRPS to persistent CRPS are needed to investigate whether serum sIL-2R levels can be used to monitor T-cell mediated inflammatory syndrome activity.

Reigniting hope in cancer treatment: the promise and pitfalls of IL-2 and IL-2R targeting strategies

Interleukin-2 (IL-2) and its receptor (IL-2R) are essential in orchestrating immune responses. Their function and expression in the tumor microenvironment make them attractive targets for immunotherapy, leading to the development of IL-2/IL-2R-targeted therapeutic strategies. However, the dynamic interplay between IL-2/IL-2R and various immune cells and their dual roles in promoting immune activation and tolerance presents a complex landscape for clinical exploitation. This review discusses the pivotal roles of IL-2 and IL-2R in tumorigenesis, shedding light on their potential as diagnostic and prognostic markers and their therapeutic manipulation in cancer. It underlines the necessity to balance the anti-tumor activity with regulatory T-cell expansion and evaluates strategies such as dose optimization and selective targeting for enhanced therapeutic effectiveness. The article explores recent advancements in the field, including developing genetically engineered IL-2 variants, combining IL-2/IL-2R-targeted therapies with other cancer treatments, and the potential benefits of a multidimensional approach integrating molecular profiling, immunological analyses, and clinical data. The review concludes that a deeper understanding of IL-2/IL-2R interactions within the tumor microenvironment is crucial for realizing the full potential of IL-2-based therapies, heralding the promise of improved outcomes for cancer patients.

Markers of extracellular matrix remodeling and systemic inflammation in patients with heritable thoracic aortic diseases

Background

In approximately 20% of patients with thoracic aortic aneurysms or dissections a heritable thoracic aortic disease (HTAD) is suspected. Several monogenic connective tissue diseases imply high risk of aortic disease, including both non-syndromic and syndromic forms. There are some studies assessing inflammation and extracellular matrix remodeling in patients with non-hereditary aortic disease, but such studies in patients with hereditary diseases are scarce.

Aims

To quantify markers of extracellular matrix (ECM) and inflammation in patients with vascular connective tissue diseases versus healthy controls.

Methods

Patients with Loeys-Dietz syndrome (LDS, n = 12), Marfan syndrome (MFS, n = 11), and familial thoracic aortic aneurysm 6 (FTAA6, n = 9), i.e., actin alpha 2 (ACTA2) pathogenic variants, were recruited. Exome or genome sequencing was performed for genetic diagnosis. Several markers of inflammation and ECM remodeling were measured in plasma by enzyme immunoassays. Flow cytometry of T-cell subpopulations was performed on a subgroup of patients. For comparison, blood samples were drawn from 14 healthy controls.

Results

(i) All groups of HTAD patients had increased levels matrix metalloproteinase-9 (MMP-9) as compared with healthy controls, also in adjusted analyses, reflecting altered ECM remodeling. (ii) LDS patients had increased levels of pentraxin 3 (PTX3), reflecting systemic inflammation. (iii) LDS patients have increased levels of soluble CD25, a marker of T-cell activation.

Conclusion

Our data suggest that upregulated MMP-9, a matrix degrading enzyme, is a common feature of several subgroups of HTAD. In addition, LDS patients have increased levels of PTX3 reflecting systemic and in particular vascular inflammation.

Soluble interleukin-2 receptor serum levels facilitate prediction of relapses in subgroups of patients with juvenile idiopathic arthritis

OBJECTIVES

JIA is characterised by a chronic disease course. Once patients achieve a state of inactive disease, there are no established biomarkers to predict the further course of inflammation for these patients. Therefore, the purpose of this study was to quantify serum biomarkers during quiescent disease to evaluate their use in identifying JIA patients at risk for future disease flare.

METHODS

Patients with non-systemic JIA reaching inactive disease status were divided into two groups: 92 patients with future active disease after a median period of 6 months (range 3-9) and 80 patients with persistent inactive disease for the following period (median 11 months, range 7-16) according to the juvenile arthritis DAS (JADAS). Clinical parameters and serum levels of various biomarkers were measured in the state of inactive disease using immunoassays in both groups and were analysed for their potential to predict the further course of disease.

RESULTS

Soluble interleukin-2 receptor (sIL-2R) serum levels were significantly higher in patients with future active disease (P = 0.021), which especially applied to patients with RF-negative polyarticular and extended oligoarticular JIA (P < 0.001). Higher sIL-2R serum levels during inactive disease were associated with a greater number of active joints at future active disease.

CONCLUSION

Patients without clinical signs of disease activity already presented with increased sIL-2R serum levels several months before disease relapses, whereas conventional inflammation parameters were not elevated. Determination of sIL-2R serum levels during inactive disease may facilitate identifying patients with subclinical disease activity at risk for future active disease.

Precursors to Systemic Sclerosis and Systemic Lupus Erythematosus: From Undifferentiated Connective Tissue Disease to the Development of Identifiable Connective Tissue Diseases

The pathogenesis of connective tissue diseases (CTDs), such as systemic lupus erythematosus (SLE) and systemic sclerosis (SSc), is characterized by derangements of the innate and adaptive immune system, and inflammatory pathways leading to autoimmunity, chronic cytokine production, and chronic inflammation. The diagnosis of these diseases is based on meeting established criteria with symptoms, signs and autoantibodies. However, there are pre-clinical states where criteria are not fulfilled but biochemical and autoimmune derangements are present. Understanding the underlying processes responsible for disease pathogenesis in pre-clinical states, which place patients at increased risk for the development of established connective tissue diseases, represents an opportunity for early identification and potentially enables timely treatment with the goal of limiting disease progression and improved prognosis. This scoping review describes the role of the innate and adaptive immune responses in the pre-clinical states of undifferentiated CTD at risk for SSc and prescleroderma, the evolution of antibodies from nonspecific to specific antinuclear antibodies prior to SLE development, and the signaling pathways and inflammatory markers of fibroblast, endothelial, and T cell activation underlying immune dysregulation in these pre-clinical states.

Impaired activation of STAT5 upon IL-2 stimulation in Tregs and elevated sIL-2R in Sjögren's syndrome

Background

Interleukin-2 (IL-2) and the high-affinity IL-2 receptor (IL-2R) are essential for the survival of regulatory T cells (Tregs) which are the main players in immune tolerance and prevention of autoimmune diseases. Sjögren’s syndrome (SS) is a chronic autoimmune disease predominantly affecting women and is characterised by sicca symptoms including oral and ocular dryness. The aim of this study was to investigate an association between IL-2R and Treg function in patients with SS of different severity defined by the salivary flow rate.

Methods

In a cross-sectional study, we determined plasma soluble IL-2R (sIL-2R) levels in women with SS (n=97) and healthy females (n=50) using ELISA. A subset of those (n=51) was screened for Treg function measured by the STAT5 signalling response to IL-2 using phospho-flow cytometry.

Results

We found that elevated plasma levels of sIL-2R were positively associated with the severity of SS reflected by a pathologically low salivary flow. Phospho-flow analysis revealed that patients with SS have a significantly lower frequency of pSTAT5⁺ Tregs upon IL-2 stimulation compared with healthy individuals, while the frequency of Tregs and pSTAT5 in conventional T cells remained unchanged. In addition, we observed more pSTAT5⁺ Tregs at baseline in patients with SS, which is significantly associated with seropositivity and elevated sIL-2R.

Conclusions

Our data indicates that Tregs have a weakened immunosuppressive function in patients with SS due to impaired IL-2/IL-2R signalling capacity. This could mediate lymphocytic infiltration into salivary glands inducing sicca symptoms. We believe that sIL-2R could act as a useful indicator for SS and disease severity.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13075-022-02769-y.

Predicting T‐cell quality during manufacturing through an artificial intelligence‐based integrative multiomics analytical platform

Large‐scale, reproducible manufacturing of therapeutic cells with consistently high quality is vital for translation to clinically effective and widely accessible cell therapies. However, the biological and logistical complexity of manufacturing a living product, including challenges associated with their inherent variability and uncertainties of process parameters, currently make it difficult to achieve predictable cell‐product quality. Using a degradable microscaffold‐based T‐cell process, we developed an artificial intelligence (AI)‐driven experimental‐computational platform to identify a set of critical process parameters and critical quality attributes from heterogeneous, high‐dimensional, time‐dependent multiomics data, measurable during early stages of manufacturing and predictive of end‐of‐manufacturing product quality. Sequential, design‐of‐experiment‐based studies, coupled with an agnostic machine‐learning framework, were used to extract feature combinations from early in‐culture media assessment that were highly predictive of the end‐product CD4/CD8 ratio and total live CD4⁺ and CD8⁺ naïve and central memory T cells (CD63L⁺CCR7⁺). Our results demonstrate a broadly applicable platform tool to predict end‐product quality and composition from early time point in‐process measurements during therapeutic cell manufacturing.

Correlation Between Thymoma and Soluble Interleukin-2 Receptor Expression in a Patient with Good Syndrome

Good syndrome is a rare condition characterized by the presence of thymoma in combination with adult-onset hypogammaglobulinemia. Immunological features of Good syndrome include various immunodeficiencies accompanied with hypogammaglobulinemia. In patients with thymoma, paraneoplastic syndromes including hypogammaglobulinemia worsen the prognosis. We herein describe a patient with advanced-stage type A thymoma who was effectively treated with chemotherapy and exhibited a parallel decrease in the serum level of soluble interleukin-2 receptor (sIL-2R), which depends on cellular immunity. The present case suggests the efficacy of sIL-2R as a potential prognostic biomarker in a subset of patients with Good syndrome.

New Tool for Rapid and Accurate Detection of Interleukin-2 and Soluble Interleukin-2 Receptor α in Cancer Diagnosis Using a Bioresponsive Microgel and Multivalent Protein Binding

Interleukin-2 (IL-2) and its α receptor in soluble form (sIL-2Rα) are considered biomarkers for cancers and immune-related diseases. Enzyme-linked immunosorbent assay is the most common method used to evaluate biomarkers in clinical practice; it is precise but time-consuming and involves complicated procedures. Here, we have developed a rapid yet accurate modality for cancer diagnosis that enables on-site evaluation of cancer markers, that is, IL-2 and sIL-2Rα, without complicated pretreatment of cancer patient-derived blood samples. Surface plasmon resonance and bioresponsive microgels conjugated with IL-2 receptors, that is, IL-2Rβ and IL-2Rγ, were utilized to measure IL-2 and sIL-2Rα levels via multivalent protein binding (MPB) between the ligands and their receptors. Our results showed that this novel method enables us to perform cancer diagnosis with a 1000-fold dilution of serum in 10 min. The advantage of MPB-based cancer diagnosis originates from its great selectivity for a target molecule and tolerance to a myriad of nonspecific substances in serum, which allows on-site clinical evaluation. Importantly, our finding implies that MPB-based cancer diagnosis provides a new paradigm not only for improving cancer treatment but also for evaluating a target molecule in unpurified and complex solutions such as blood.

Biomarkers of systemic inflammation, soluble IL-2Rα and the multiple sclerosis-associated IL2RA SNP rs2104286 in healthy subjects and multiple sclerosis patients

Soluble interleukin-2 (IL-2) receptor α (sIL-2Rα) antagonizes IL-2 signaling and is involved in the pathogenesis of several immune-mediated diseases including multiple sclerosis (MS). The level of sIL-2Rα is affected by the MS-associated single nucleotide polymorphism (SNP) rs2104286. By use of ELISA and electrochemiluminescence, we investigated if 26 biomarkers of systemic inflammation were associated with sIL-2Rα and rs2104286 in cohorts of healthy subjects and MS patients in serum and heparin plasma. We found that sIL-2Rα significantly correlated with the level of tumor necrosis factor-α (TNFα) (r = 0.391, p = 0.002) in healthy subjects and the association was validated in a separate cohort. Additional, in healthy subjects we confirmed a previous report indicating that C-reactive protein (CRP) correlates with sIL-2Rα (r = 0.278, p = 0.034). None of the biomarkers of systemic inflammation were significantly associated with sIL-2Rα in MS patients. Furthermore, the MS-associated SNP rs2104286 was not significantly associated with any of the biomarkers of systemic inflammation in neither healthy subjects nor MS patients. We conclude that sIL-2Rα is associated with TNFα and CRP in healthy subjects. However, further research is required to confirm the use of sIL-2Rα as biomarker of systemic inflammation as well as to assess the mechanism underlying the observed correlation between levels of sIL-2Rα and TNFα.

Soluble interleukin-2 receptor as a predictive and prognostic marker for patients with familial breast cancer

The incidence of breast cancer increases annually, and it has become common within families of breast cancer patients. Interleukin-2 activates cytotoxic T lymphocytes, which are important for cancer immunity. To identify markers of increased familial breast cancer risk, soluble interleukin-2 receptor levels and immunologic factors were investigated in familial breast cancer and non-familial breast cancer patients. Of 106 untreated breast cancer patients in this study, 24 had familial breast cancer and 82 had non-familial breast cancer. The patients' soluble interleukin-2 receptor, interleukin-10, vascular endothelial growth factor, interleukin-17, regulatory T cell, myeloid-derived suppressor cell, white blood cell, and C-reactive protein levels, and their neutrophil-to-lymphocyte ratios were measured, and their prognoses were compared according to the soluble interleukin-2 receptor levels. Additionally, postoperative tissues from the patients with high soluble interleukin-2 receptor levels were stained with programmed cell death ligand 1 and cluster of differentiation 8. The soluble interleukin-2 receptor level in the familial breast cancer patients was significantly higher, and it showed significantly stronger correlations with the neutrophil-to-lymphocyte ratio and the interleukin-10, vascular endothelial growth factor, interleukin-17, regulatory T cell, myeloid-derived suppressor cell, white blood cell, and C-reactive protein levels, than in the non-familial breast cancer patients. The regulatory T cell and myeloid-derived suppressor cell levels were significantly higher in the patients with high soluble interleukin-2 receptor levels, and the overall survival and disease-free-survival rates were significantly worse for the familial breast cancer patients than for the non-familial breast cancer patients. Triple-negative breast cancer tissues from the familial breast cancer patients with high soluble interleukin-2 receptor levels stained well for programmed cell death ligand 1 and cluster of differentiation 8. Soluble interleukin-2 receptor levels can be used to predict the prognosis of familial breast cancer patients. Prospectively identifying patients who are less likely to have non-familial breast cancer is vital for improving their overall survival.

Do COVID-19 Infections Result in a Different Form of Secondary Hemophagocytic Lymphohistiocytosis

The coronavirus disease 2019 (COVID-19) pandemic, caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has resulted in significant morbidity and mortality across the world, with no current effective treatments available. Recent studies suggest the possibility of a cytokine storm associated with severe COVID-19, similar to the biochemical profile seen in hemophagocytic lymphohistiocytosis (HLH), raising the question of possible benefits that could be derived from targeted immunosuppression in severe COVID-19 patients. We reviewed the literature regarding the diagnosis and features of HLH, particularly secondary HLH, and aimed to identify gaps in the literature to truly clarify the existence of a COVID-19 associated HLH. Diagnostic criteria such as HScore or HLH-2004 may have suboptimal performance in identifying COVID-19 HLH-like presentations, and criteria such as soluble CD163, NK cell activity, or other novel biomarkers may be more useful in identifying this entity.

Breast cancer therapy affects the expression of antineonatal Nav1.5 antibodies in the serum of patients with breast cancer

Neonatal Nav1.5 (nNav1.5) is the alternative splice variant of Nav1.5 and it has been widely associated with the progression of breast cancer. The immunological context of nNav1.5 with respect to breast cancer metastases remains unexplored. The presence of antibodies against nNav1.5 may highlight the immunogenicity of nNav1.5. Hence, the aim of the present study was to detect the presence of antineonatal Nav1.5 antibodies (antinNav1.5-Ab) in the serum of patients with breast cancer and to elucidate the effects of breast cancer therapy on its expression. A total of 32 healthy female volunteers and 64 patients with breast cancer were randomly recruited into the present study as the control and breast cancer group, respectively. Patients with breast cancer were divided equally based on their pre- and ongoing-treatment status. Serum samples were tested with in-house indirect enzyme-linked immunosorbent assay (ELISA) to detect antinNav1.5-Ab, CD25 (T regulatory cell marker) using an ELISA kit and Luminex assay to detect the expression of metastasis-associated cytokines, such as vascular endothelial growth factor (VEGF), interleukin (IL)-6, IL-10, IL-8, chemokine (C-C motif) ligand 2 and tumor necrosis factor-alpha (TNF-α) The mean difference in the expression of antinNav1.5-Ab among the three groups (control, pretreatment and ongoing-treatment) was significant (P=0.0005) and the pretreatment breast cancer group exhibited the highest expression. The concentration of CD25 was highest in the pretreatment breast cancer group compared with the control and ongoing-treatment groups. There was a significant positive correlation between antinNav1.5-Ab and IL-6 in the pretreatment group (r=0.7260; P=0.0210) and a significant negative correlation between antinNav1.5-Ab and VEGF in the ongoing-treatment group (r=-0.842; P-value=0.0040). The high expression of antinNav1.5-Ab in the pretreatment group was in accordance with the uninterrupted presence of metastasis and highlighted the immunogenicity of nNav1.5 whereas the low expression of antinNav1.5-Ab in the ongoing-treatment group reflected the efficacy of breast cancer therapy in eliminating metastases. The augmented manifestation of T regulatory cells in the pretreatment group highlighted the functional role of nNav1.5 in promoting metastasis. The parallel expression of antinNav1.5-Ab with the imbalanced expression of cytokines promoting metastasis (IL-8, IL-6 and TNF-α) and cytokines that prevent metastasis (IL-10) indicated the role of nNav1.5 in breast cancer growth. The expression of antinNav1.5-Ab in accordance to the metastatic microenvironment indicates the immunogenicity of the protein and highlights the influence of breast cancer therapy on its expression level.

The significance of serum levels of soluble interleukin-2 receptor in patients undergoing maintenance hemodialysis

Background

Elevated serum levels of sIL-2R are commonly observed in patients undergoing maintenance hemodialysis (MHD). However, the clinical implications in these subjects are unclear. This study is aimed to assess the significance of elevated sIL-2R levels in MHD patients.

Methods

A total of 382 MHD patients were followed-up from September 2016 to December 2019. Patients were divided into two groups: high sIL-2R, with sIL-2R levels ≥2-fold of the upper limit of normal (710 U/ml); and low sIL-2R, with sIL-2R levels < 2-fold the upper limit of normal. The relationships between sIL-2R levels and other clinical parameters, as well as patient prognosis were both assessed.

Results

The median concentration of sIL-2R was 1268 U/mL. A total of 372 (97.38%) patients exhibited sIL-2R levels higher than the upper limit of the normal range. Multiple linear regression analysis revealed that monocyte count (β = 0.1571, p = 0.01), and β₂-MG (β = 0.2635, p < 0.0001), hemoglobin (β = −0.1610, p = 0.001), SCr (β = −0.3471, p < 0.0001), and HDL-C (β = −0.1091, p = 0.029) levels were independent factors influencing serum concentrations of sIL-2R. High sIL-2R was significantly correlated with non-cardiovascular-related mortality (OR 2.97 [95% CI 1.59–5.56; p = 0.001), of which 39 (82.98%) were attributed to infection and/or cancer.

Conclusions

Elevated sIL-2R is prevalent in MHD patients and related with several unfavorable parameters. sIL-2R appears to have no ability to predict cardiovascular mortality, which accounts for approximately one-half of all deaths. However, sIL-2R may be beneficial in predicting noncardiovascular mortality.

Serum Soluble Interleukin-2 Receptor Does Not Differentiate Complex Regional Pain Syndrome from Other Pain Conditions in a Tertiary Referral Setting

Previously, we showed that serum soluble interleukin-2 receptor (sIL-2R) levels, a marker for T-cell activation, were higher in complex regional pain syndrome (CRPS) patients than in healthy controls, suggesting pathogenic T-cell activation in CRPS. Additionally, sIL-2R levels discriminated well between CRPS and healthy controls with a high sensitivity (90%) and specificity (89.5%), suggesting a possible role for sIL-2R in the diagnosis of CRPS. In order to further validate this marker in the diagnostic workup of CRPS, we conducted this prospective cohort study in which we determined sIL-2R levels in patients that were referred to our tertiary referral center with a suspicion of CRPS in a limb, and subsequently compared sIL-2R levels between the patients that were diagnosed with CRPS (CRPS group) and those who were not (no CRPS group). A group of anonymous blood bank donors were used as a healthy control group. Furthermore, we explored the relationship between sIL-2R and CRPS disease severity using the CRPS severity score. Median sIL-2R levels of both the CRPS group (2809.0 pg/ml; Q3-Q1: 3913.0-1589.0) and no CRPS group (3654.0 pg/ml; Q3-Q1: 4429.0-2095.5) were significantly higher than that of the control group (1515.0 pg/ml; Q3-Q1: 1880.0-1150.0): CRPS vs. controls, p < .001; no CRPS vs. controls, p < 0.001. Serum sIL-2R levels did not differ significantly between the CRPS and no CRPS group. A statistically significant negative correlation was observed between sIL-2R levels and the CRPS severity score (r_s = −0.468, p = 0.024). Our results confirm our previous findings of higher sIL-2R levels in CRPS patients than in healthy controls. We further showed that serum sIL-2R cannot differentiate between CRPS and other pain conditions of a limb in a tertiary referral setting. Interestingly, a negative correlation was found between sIL-2R and CRPS disease severity; this finding warrants further research into the relationship between sIL-2R and CRPS disease severity.

Obesity-associated T-cell and macrophage activation improve partly after a lifestyle intervention

BACKGROUND

The relation between low-grade inflammation and metabolic dysfunction in obesity is not fully explored.

OBJECTIVE

To evaluate immune parameters in the obese state and after a lifestyle intervention program.

METHODS

Patients with obesity (n = 87) from an academic obesity clinic were compared with controls with regard to macrophage and T-cell activation (reflected by serum levels of soluble CD163 (sCD163) and soluble IL-2 receptor (sIL-2R), respectively), and an array of cytokines, chemokines, and growth factors. In addition, these parameters and regulatory T-cells (Treg), were studied in 27 patients who followed a 75-week lifestyle intervention (dietary advice, exercise, and psychoeducation).

RESULTS

Mean sIL-2R and sCD163 levels were higher in patients than controls (sIL-2R:2884 ± 936 pg/ml vs. 2207 ± 813 pg/ml, p = 0.001; sCD163:1279 ± 580 pg/ml vs. 661 ± 271 pg/ml, p < 0.0001 respectively). Patients with metabolic syndrome (MetS) had higher sCD163 than those without (1467 ± 656 pg/ml vs. 1103 ± 438 pg/ml). Patients had higher IL-1β, IL-1RA, IL-2, IL-4, IL-5, IL-6, IL-8, IL-9, IL-10, IL-15, IL-17A, MCP-1/CCL2, MIP-1α/CCL3, MIP-1β/CCL4, G-CSF, GM-CSF, FGF, IFN-γ, and TNF-α than controls, whereas VEGF-A, PDGF-BB, and eotaxin were lower. Upon intervention, sIL-2R decreased while peripheral Treg frequencies increased within the reference range (p = 0.042 and p = 0.005 respectively). The sIL-2R decrease correlated to a decrease in waist circumference (rho = 0.388, p = 0.045) and in trend to a decrease in MetS components (rho = 0.345, p = 0.078). The Treg increase was unrelated to weight loss or metabolic improvement. Mean sCD163 did not change significantly upon intervention, nor did the cytokines, chemokines, and growth factors (except IP-10/CXCL10).

CONCLUSION

In obesity, T-cell homeostasis improves after a lifestyle intervention. Immunologic alterations can occur independently of metabolic improvement.

The IL-2 - IL-2 receptor pathway in health and disease: The role of the soluble IL-2 receptor

The interleukin (IL)-2 - IL-2 receptor (IL-2R) pathway is important in immunity, but is also involved in maintenance of self-tolerance. This paradox is further complicated by shedding of the IL-2Rα chain, revealing soluble (s)IL-2R. Binding of IL-2 to sIL-2R may either reduce or enhance responses depending on the target cell being involved in immunity or self-tolerance. Since sIL-2R levels are increasingly measured in clinical practice, it is detrimental for clinical interpretation to understand the possible functional impact of IL-2R shedding. In this review the role of the IL-2 - IL-2R pathway is explored and the conflicting results on the function of sIL-2R are summarized. Finally, the added value of measuring sIL-2R in different types of diseases is being elaborated upon in terms of diagnosis, follow-up, and prognosis. Adequate interpretation of results is hampered by the apparent gap in our knowledge about the functional role of sIL-2R in immunity and tolerance.

Clinical usefulness of very high serum soluble interleukin-2 receptor levels for the detection of tuberculous peritonitis in a patient with chronic myelogenous leukemia

Tuberculous peritonitis is difficult to diagnose due to the disadvantages of ascitic culture and peritoneal biopsy. Although previous reports suggested that very high serum soluble interleukin-2 receptor (sIL-2R) levels may reflect the clinical activity of tuberculosis, little is known about the diagnostic utility of serum sIL-2R for tuberculous peritonitis. We describe a case of tuberculous peritonitis with chronic myelogenous leukemia. The abnormally high serum sIL-2R value and negative findings for other possible causes including lymphoma suggested tuberculous peritonitis and we administered anti-tuberculosis treatment before definitive diagnosis. Abnormally high serum sIL-2R levels may contribute to earlier diagnosis of tuberculous peritonitis, along with ruling out other potential differential diagnoses.

Soluble interleukin-2 receptor (sIL-2r) level is a limited test for the diagnosis of adult secondary hemophagocytic lymphohistiocytosis

BACKGROUND

Soluble interleukin-2 receptor (sIL-2r) level is used as a diagnostic tool in hemophagocytic lymphohistiocytosis (HLH). However, evidence supporting its use among adults is inadequate.

OBJECTIVE AND METHODS

We conducted a retrospective study to assess the performance characteristics of sIL-2r for the diagnosis of adult HLH.

RESULTS

One hundred thirty-two adults with sIL-2r levels sent for evaluation of HLH over a ten-year period were included. Sixty-five (49%) met criteria for HLH. Mean sIL-2r was significantly higher among patients with HLH relative to all patients without HLH (12942U/ml vs. 6308 U/mL, P = .00311). However, when comparing mean sIL-2r in the HLH group to those in the non-HLH group with primary diagnoses of hematologic malignancy (8911 U/mL), sepsis (7127 U/mL), and rheumatologic disease (4624 U/mL), no significant differences were found (P = .241, P = .178, and P = .0607, respectively). There was only weak correlation between sIL-2r and diagnosis of HLH (r = .253). The standard cutoff sIL-2r > 2400 U/ml yielded a sensitivity of 89.2% and specificity of 38.8%. The area under the curve for the corresponding receiver-operator curve was 0.691, consistent with a poor discriminating ability for the diagnosis of HLH.

CONCLUSIONS

sIL-2r is a limited test for the diagnosis of adult secondary HLH, and its role in this setting should be reevaluated.

Highlighting the Role of Biomarkers of Inflammation in the Diagnosis and Management of Complex Regional Pain Syndrome

Complex regional pain syndrome (CRPS) is characterized by continuous pain that is often accompanied by sensory, motor, vasomotor, sudomotor, and trophic disturbances. If left untreated, it can have a significant impact on the quality of life of patients. The diagnosis of CRPS is currently based on a set of relatively subjective clinical criteria: the New International Association for the Study of Pain clinical diagnostic criteria for CRPS. There are still no objective laboratory tests to diagnose CRPS and there is a great need for simple, objective, and easily measurable biomarkers in the diagnosis and management of this disease. In this review, we discuss the role of inflammation in the multi-mechanism pathophysiology of CRPS and highlight the application of potential biomarkers of inflammation in the diagnosis and management of this disease.

Increased Plasma Soluble Interleukin-2 Receptor Alpha Levels in Patients With Long-Term Type 1 Diabetes With Vascular Complications Associated With IL2RA and PTPN2 Gene Polymorphisms

Type 1 diabetes (T1D) is largely considered an autoimmune disease leading to the destruction of insulin-producing pancreatic β cells. Further, patients with T1D have 3-4-fold increased risk of developing micro- and macrovascular complications. However, the contribution of immune-related factors contributing to these diabetes complications are poorly understood. Individuals with long-term T1D who do not progress to vascular complications offer a great potential to evaluate end-organ protection. The aim of the present study was to investigate the association of inflammatory protein levels with vascular complications (retinopathy, nephropathy, cardiovascular disease) in individuals with long-term T1D compared to individuals who rapidly progressed to complications. We studied a panel of inflammatory markers in plasma of patients with long-term T1D with (n = 81 and 26) and without (n = 313 and 25) vascular complications from two cross-sectional Scandinavian cohorts (PROLONG and DIALONG) using Luminex technology. A subset of PROLONG individuals (n = 61) was screened for circulating immune cells using multicolor flow cytometry. We found that elevated plasma levels of soluble interleukin-2 receptor alpha (sIL-2R) were positively associated with the complication phenotype. Risk carriers of polymorphisms in the IL2RA and PTPN2 gene region had elevated plasma levels of sIL-2R. In addition, cell surface marker analysis revealed a shift from naïve to effector T cells in T1D individuals with vascular complications as compared to those without. In contrast, no difference between the groups was observed either in IL-2R cell surface expression or in regulatory T cell population size. In conclusion, our data indicates that IL2RA and PTPN2 gene variants might increase the risk of developing vascular complications in people with T1D, by affecting sIL-2R plasma levels and potentially lowering T cell responsiveness. Thus, elevated sIL-2R plasma levels may serve as a biomarker in monitoring the risk for developing diabetic complications and thereby improve patient care.

Sensitivity and specificity of serum soluble interleukin-2 receptor for diagnosing sarcoidosis in a population of patients suspected of sarcoidosis

Background

The soluble interleukin 2 receptor (sIL-2R) has been proposed as a marker of disease activity in patients with sarcoidosis. However, no studies have evaluated whether serum sIL-2R measurement is of use in establishing the diagnosis of sarcoidosis in patients who are suspected of sarcoidosis among other diseases.

Methods

A cohort study was conducted, consisting of new patients who visited the immunology outpatient clinic and whose serum sIL-2R levels were available before a definitive diagnosis was established between February 2011 and February 2016. All patients underwent standard diagnostic testing for sarcoidosis (e.g. laboratory tests, radiographic and/or nuclear imaging and/or affected site biopsy). This resulted either in the diagnosis of sarcoidosis or the exclusion of sarcoidosis with the diagnosis of another disease. Results of sIL-2R and angiotensin-converting enzyme (ACE) levels, radiographic and nuclear imaging and histology results were collected and definitive diagnoses were recorded. Sensitivity, specificity, the concordance statistic from the receiver operating characteristic curve and Youden’s Index were calculated to assess the performance of sIL-2R in the diagnosis of sarcoidosis and were compared to ACE, currently one of the most used diagnostic biomarkers in the diagnosis of sarcoidosis.

Results

In total 983 patients were screened for inclusion, of which 189 patients met the inclusion criteria. A total of 101 patients were diagnosed with sarcoidosis after diagnostic workup, of whom 79 were biopsy-proven. In 88 patients a diagnosis other than sarcoidosis was made. The sensitivity and specificity of serum soluble interleukin 2 receptor levels to detect sarcoidosis were 88% and 85%. The sensitivity and specificity of ACE were 62% and 76%. Receiver operating characteristic curve analysis revealed that sIL-2R receptor is superior to ACE (p<0.0001).

Conclusion

Serum sIL-2R is a sensitive biomarker and superior to ACE in establishing the diagnosis of sarcoidosis and can be used to rule out sarcoidosis in patients suspected of sarcoidosis.

Biomarkers of Systemic Lupus Erythematosus and Systemic Sclerosis diseases activity in a sample of Egyptian patients :Soluble Intercellular Adhesion Molecule-1 and Soluble Interleukin-2 Receptor, Case Control Study

Systemic Lupus Erythematosus (SLE) and systemic sclerosis (SSc) are systemic inflammatory autoimmune disorders characterized by a large spectrum of clinical and laboratory features. The aim of the present study was to investigate the possible use of serum level of soluble intercellular adhesion molecule-1(sICAM-1) and soluble interleukin-2 receptor (sIL-2Ra) as biomarkers for monitoring of SLE and SSc disease activity. Moreover, it aimed to compare the specificity and sensitivity as well as cut-off value of both biomarkers in a sample of Egyptian patients. 50 SLE patients, 30 SSc patients and 60 age and sex matched healthy controls were enrolled in our study. sICAM-1and sIL-2Ra were measured in serum samples obtained from all participants. In addition to Erythosedimentation rate (ESR), complete blood count (CBC), Antineuclearantibodies (ANA) estimation, disease activity of both diseases were also assessed. sICAM-1and sIL-2Ra levels were higher in SLE and SSc patients versus control. Both parameters are correlated with each other as well as the activity parameters. A cut-off levels of 455.59 (ng/ml) &2525935 (pg/ml) in both SLE & SSs respectively was observed with the highest specificity and sensitivity. It could be concluded that sICAM-1 and sIL-2Ra are noninvasive biomarkers for SLE and SSc that could play a pathophysiologic role in development and progression of both diseases. Moreover, sICAM-1 and sIL-2Ra are correlated with the disease activity at cut-off values of 455.59 (ng/ml) & 2525935(pg/ml) respectively.

Development, analytical validation, and initial clinical evaluation of a radioimmunoassay for the measurement of soluble CD25 concentrations in canine serum

During immune activation, CD25 is expressed by T cells, and its soluble form (sCD25) is released into the extracellular matrix and the bloodstream. In humans, serum sCD25 concentrations are used as a surrogate marker for autoimmune diseases, malignancies, and transplant rejection. However, a canine-specific assay for the measurement of sCD25 in dog serum has not previously been described. Therefore, the aims of this study were to develop and analytically validate a radioimmunoassay to measure sCD25 in canine serum, to establish a reference interval for canine sCD25, and to test the clinical utility of this assay with serum samples for dogs with various diseases. A competitive radioimmunoassay (RIA) was developed and analytically validated. Analytical validation consisted of lower limit of detection (LLOD), dilutional parallelism, spiking recovery, and intra- and inter-assay variability using pooled surplus canine serum samples. A reference interval was established in healthy dogs and serum samples from dogs with various types of neoplasia, IBD, liver disease, suspected pancreatitis, or suspected small intestinal disease and serum samples with an increased C-reactive protein concentration (CRP) were analyzed to test the clinical utility of the assay. LLOD was calculated to be 0.5 ng/mL. The mean (±SD) observed-to-expected ratio (O/E) for serial dilutions was 101.7 ± 14.0%, and the mean (± SD) O/E for spiking recovery was 93.2 ± 4.2%. Coefficients of variation (CVs) for intra-assay variability were ≤12.5% (mean ± SD: 7.5 ± 4.2%), and inter-assay CVs were ≤15.7% (mean ± SD: 11 ± 4.4%). A reference interval (RI) for canine sCD25 of 1.2-4.2 ng/mL was established from a population of 112 clinically healthy dogs. Dogs with neoplasia and dogs with suspected small intestinal disease had decreased concentrations of serum sCD25 when compared to healthy dogs (p < 0.0001, respectively). However, the majority of clinical samples used in this study were within the reference interval. Median concentrations of serum sCD25 were 1.9 ng/mL for healthy dogs. Dogs with cancer, IBD, liver disease, suspected pancreatitis, or suspected small intestinal disease, as well as sera with an increased serum CRP concentration, had median serum sCD25 concentrations of 1.6 ng/mL, 2.1 ng/mL, 2.2 ng/mL, 1.7 ng/mL, 1.5 ng/mL, and 1.8 ng/mL, respectively. Thus, the RIA described here is linear, accurate, precise, and reproducible for measuring sCD25 in canine serum. However, this assay shows little clinical utility of sCD25 as a biomarker for dogs with inflammatory, autoimmune, and/or neoplastic conditions.

Inflammatory markers are altered in severe mental disorders independent of comorbid cardiometabolic disease risk factors

BACKGROUND

Inflammation and immune activation have been implicated in the pathogenesis of severe mental disorders and cardiovascular disease (CVD). Despite high level of comorbidity, many studies of the immune system in severe mental disorders have not systematically taken cardiometabolic risk factors into account.

METHODS

We investigated if inflammatory markers were increased in schizophrenia (SCZ) and affective (AFF) disorders independently of comorbid CVD risk factors. Cardiometabolic risk factors (blood lipids, body mass index and glucose) and CVD-related inflammatory markers CXCL16, soluble interleukin-2 receptor (sIL-2R), soluble CD14 (sCD14), macrophage inhibitory factor and activated leukocyte cell adhesion molecule (ALCAM) were measured in n = 992 patients (SCZ, AFF), and n = 647 healthy controls. We analyzed the inflammatory markers before and after controlling for comorbid cardiometabolic risk factors, and tested for association with psychotropic medication and symptom levels.

RESULTS

CXCL16 (p = 0.03) and sIL-2R (p = 7.8 × 10-5) were higher, while sCD14 (p = 0.05) were lower in patients compared to controls after controlling for confounders, with significant differences in SCZ for CXCL16 (p = 0.04) and sIL-2R (p = 1.1 × 10-5). After adjustment for cardiometabolic risk factors higher levels of sIL-2R (p = 0.001) and lower sCD14 (p = 0.002) remained, also in SCZ (sIL-2R, p = 3.0 × 10-4 and sCD14, p = 0.01). The adjustment revealed lower ALCAM levels (p = 0.03) in patients. We found no significant associations with psychotropic medication or symptom levels.

CONCLUSION

The results indicate that inflammation, in particular enhanced T cell activation and impaired monocyte activation, are associated with severe mental disorders independent of comorbid cardiometabolic risk factors. This suggests a role of novel pathophysiological mechanisms in severe mental disorders, particularly SCZ.

Biomarkers in IgG4-related disease: A systematic review

OBJECTIVE

ImmunoglobulinG4-related disease (IgG4-RD) is a recently recognized disease and, as such, there is a pressing need to identify biomarkers for diagnosis, monitoring disease activity, and predicting prognosis and response to therapy. Here, we review the recent development and identification of biomarkers for IgG4-RD.

METHODS

Through extensive literature review and analysis, we updated the biomarkers for IgG4-RD and further put forward our own viewpoints.

RESULTS

In addition to traditional biomarkers, such as serum IgG4 concentration and typical histological characteristics, several novel indicators, including IgG2, serum soluble IL-2 receptor (sIL2R), and cc-chemokine ligand 18 (CCL18), indicate inflammation and fibrosis and can be used to accurately diagnose and predict treatment response. Studies to identify target autoantigens in IgG4-RD have shed light on the unmet need for biomarkers that can identify this disorder. Additionally, both serological and histopathologic immune cells involved in antigen-induced responses, innate immune cells (macrophages, mast cells, and the I-IFN/ IL-33 pathway), as well as subsequent acquired immune cells (T and B cell subsets), may also serve as new biomarkers for IgG4-RD. Since IgG4-RD often clinically manifests with multiple organs involvement, non-invasive PET-CT can improve diagnosis and antidiastole levels.

CONCLUSION

These novel biomarkers provide information to help diagnose IgG4-RD, monitor disease activity, as well as predict prognosis and response to therapy.

Cathepsin S, a new serum biomarker of sarcoidosis discovered by transcriptome analysis of alveolar macrophages

Background

Development of reliable new biomarkers remains crucial to improve diagnosis and assessing disease activity in sarcoidosis. The objective of this study was to seek such markers from the gene expression signature of alveolar macrophages by transcriptome analysis.

Methods

Pooled RNA extracted from alveolar macrophages from patients with active sarcoidosis and control patients was subjected to transcriptome analysis using microarrays. Expressed gene intensity in sarcoidosis relative to that in control was calculated. We measured serum cathepsin S (CTSS) concentrations in 89 healthy volunteers, 107 patients with sarcoidosis, 26 with interstitial pneumonia, 150 with pneumoconiosis, and 76 with pulmonary mycobacteriosis by the enzyme-linked immunosorbent assay.

Results

Among 12 genes with ratios higher than that of a housekeeping gene, we selected CTSS for scrutinizing protein expression in serum because of the feasibility of the protein assay. CTSS concentrations were significantly increased in sarcoidosis compared with not only controls but also all the other lung diseases. Receiver operating characteristics curve for sarcoidosis and parenchymal lung diseases revealed an area under the curve of 0.800 (95% confidence interval, 0.751-0.850; p=1.4 x 10^-18) with 70% sensitivity and 78% specificity at a CTSS concentration of 15.5 ng/ml. A significant trend was identified between CTSS concentrations and the number of affected organs. Serum CTSS concentrations varied in parallel with clinical courses both spontaneously and in response to corticosteroid therapy. Epithelioid cells in granulomas were positive for immunohistochemical staining with CTSS.

Conclusions

CTSS has the potential to be a useful biomarker in sarcoidosis.

A prospective quality improvement initiative in adult hemophagocytic lymphohistiocytosis to improve testing and a framework to facilitate trigger identification and mitigate hemorrhage from retrospective analysis

Hemophagocytic lymphohistiocytosis (HLH) is a highly fatal, hyperinflammatory syndrome in adults triggered by an underlying illness in most cases. As such, suspicion of HLH dictates further investigation to identify the HLH trigger and determine treatment. HLH is clinically challenging due to diverse presentations and underlying triggers, provider unfamiliarity, and bleeding complications. Clinically, we observed diagnostic error from incorrect testing and cognitive biases (interleukin-2 confused with soluble interleukin-2 receptor and natural killer cell quantification confused with functional assays).This study reports our single institutional experience with adult HLH with the aim to reduce erroneous testing with a quality improvement (QI) project, and to facilitate trigger discovery and mitigate hemorrhage. Provider education on HLH testing was the prospective intervention, followed by mistaken test removal. HLH triggers and diagnostic utility were determined by retrospective chart review. Risk factors for hemorrhage were determined by multivariable analysis.Erroneous HLH testing was reduced from 74% to 24% of patients (P < .001) by the QI intervention. These changes were projected to save $11,700 yearly. The majority (64%) of patients evaluated for HLH were on non-hematology/oncology services, highlighting the need for vigilance in hematology consultation. Sixty-three patients met classic HLH-2004 criteria for HLH. Malignancy (38%), infection (27%), Epstein-Barr virus (EBV) (14%), or autoimmune disease (8%) triggered most HLH cases. HLH triggers were most commonly identified by serologic testing (27%) and bone marrow biopsy (19%). Biopsy of other affected organs based on PET-CT imaging after unsuccessful initial diagnostic measures was helpful, and focal fluorodeoxyglucose uptake was predictive of an underlying malignancy (likelihood ratio 8.3, P = .004). Major hemorrhage occurred in 41% of patients. On multivariable analysis the odds ratios (OR) for major hemorrhage were increased for patients with intensive care unit level care (OR 10.47, P = .005), and disseminated intravascular coagulation in the first week of admission (OR 10.53, P = .04).These data are incorporated into a framework to encourage early HLH recognition with the HScore, facilitate trigger identification, identify those at risk for hemorrhage, and minimize low-yield or erroneous testing.

Human Pegivirus infection and lymphoma risk and prognosis: a North American study

We evaluated the association of Human Pegivirus (HPgV) viraemia with risk of developing lymphoma, overall and by major subtypes. Because this virus has also been associated with better prognosis in the setting of co-infection with human immunodeficiency virus, we further assessed the association of HPgV with prognosis. We used risk factor data and banked plasma samples from 2094 lymphoma cases newly diagnosed between 2002 and 2009 and 1572 frequency-matched controls. Plasma samples were tested for HPgV RNA by reverse transcription polymerase chain reaction (RT-PCR), and those with RNA concentrations <5000 genome equivalents/ml were confirmed using nested RT-PCR methods. To assess the role of HPgV in lymphoma prognosis, we used 2948 cases from a cohort study of newly diagnosed lymphoma patients (included all cases from the case-control study). There was a positive association of HPgV viraemia with risk of lymphoma overall (Odds ratio = 2·14; 95% confidence interval [CI] 1·63-2·80; P < 0·0001), and for all major subtypes except Hodgkin lymphoma and chronic lymphocytic leukaemia/small lymphocytic lymphoma, and this was not confounded by other lymphoma risk factors. In contrast, there was no association of HPgV viraemia with event-free survival (Hazard ratio [HR] = 1·00; 95% CI 0·85-1·18) or overall survival (HR = 0·97; 95% CI 0·79-1·20) for lymphoma overall, or any of the subtypes. These data support the hypothesis for a role of HPgV in the aetiology of multiple lymphoma subtypes.

Soluble Interleukin-2 Receptor: A Potential Marker for Monitoring Disease Activity in IgG4-Related Disease

BACKGROUND

IgG4-related disease (IgG4-RD) is a fibroinflammatory condition. T-cells play a crucial role in the pathogenesis, and therefore, serum soluble interleukin-2 receptor (sIL-2R) may be a potential biomarker.

METHOD

We studied the levels of sIL-2R in 26 histologically proven IgG4-RD patients with available serum sIL-2R and compared them to those in newly diagnosed and untreated sarcoidosis patients (n = 78) and controls (n = 101) and the serum sIL-2R levels in patients after treatment of IgG4-RD (n = 15). The disease activity was measured using the IgG4-Related Disease Responder Index (IgG4-RD RI).

RESULTS

Median serum sIL-2R in IgG4-RD patients was 4667 pg/ml compared to 1515 pg/ml in controls (P < 0.001) and 6050 pg/ml in sarcoidosis patients (P = 0.004 compared to IgG4-RD). All IgG4-RD patients had elevated serum sIL-2R levels compared to the reference value of <2500 pg/ml in controls and 85% elevated serum IgG4; however, these did not correlate with each other. Both serum sIL-2R and IgG4 levels declined significantly after treatment (P = 0.001 and P = 0.01, resp.). Before treatment, serum sIL-2R level and IgG4-RD RI did not correlate with each other. However, the decrease in serum sIL-2R upon treatment did correlate significantly (P = 0.04) with the decrease in disease activity assessed by IgG-RD RI.

CONCLUSION

Serum sIL-2R is elevated in IgG4-RD reflecting the inflammatory process with enhanced T-cell activation. Furthermore, serum sIL-2R might serve as a potential marker of response to treatment in IgG4-RD.

Are there differences in lipid peroxidation and immune biomarkers between major depression and bipolar disorder: Effects of melancholia, atypical depression, severity of illness, episode number, suicidal ideation and prior suicide attempts

BACKGROUND

There is evidence that major depression (MDD) and bipolar disorder (BD) are accompanied by activated immune & oxidative (I&O) pathways.

METHODS

To compare I&O biomarkers between MDD and BD we assessed serum levels of thiobarbituric acid reactive substances (TBARS; a lipid peroxidation marker), soluble interleukin-2 receptor (sIL-2R), sIL-6R, IL-α, sIL-1R antagonist (sIL-1RA), tumor necrosis factor receptor 60kDa/80kDa (sTNFR60/R80) in 114 MDD and 133 BD patients, and 50 healthy controls. We computed z-unit weighted indices reflecting the 5 cytokine receptor levels (zCytR), cell-mediated immunity (zCMI) and I&O pathways (zCMI+TBARS).

RESULTS

There are no significant differences in biomarkers between MDD and BD. BD/MDD with atypical features is characterized by increased sIL-6R and TBARS, whereas melancholia is associated with higher TBARS and lower sTNFR60 levels. Severity of illness, as measured with the Hamilton Depression Rating Scale, is correlated with increased sIL-6R, sTNFR80, TBARS, zCytR and zCMI+TBARS. The number of episodes the year prior to blood sampling is positively associated with sTNFR80, TBARS, zCMI, zCMI+TBARS, while number of hospitalizations is positively associated with sIL-1RA. Prior suicidal attempts are associated with increased sIL-1RA, IL-1α, zCMI, TBARS and zCMI+TBARS, while TBARS is associated with current suicidal ideation.

CONCLUSIONS

There are no I&O biomarker differences between MDD and BD. Atypical depression is associated with increased IL-6 trans-signaling and lipid peroxidation. Severity of depression, number of episodes and suicidal attempts are associated with activated I&O pathways. Increased TBARS is the single best predictor of BD/MDD, atypical depression, melancholia and current suicidal ideation.

Candidate Serum Markers in Early Crohn's Disease: Predictors of Disease Course

BACKGROUND AND AIMS

More than half of patients with Crohn's disease [CD] develop disease complications requiring aggressive medical therapy or surgery over time. However, predicting disease course and treatment response remains difficult. We therefore identified distinctive serum analytes associated with disease activity and course in newly diagnosed, untreated patients at presentation and during their follow-up.

METHODS

In a pilot study, a multiplex immunoassay analysis on 36 markers was performed on serum from 20 CD patients at the time of primary diagnosis following endoscopic evaluation. The 12 most potent markers associated with disease activity, phenotype and course were analysed in a consecutive cohort of 66 CD patients at diagnosis and follow-up [n = 39]. A healthy control group [n = 20] was included as a reference.

RESULTS

CD patients had higher baseline levels of sTNF-R2 [p = 0.001], sIL-2R [p = 0.0001], and MMP-1 [p = 0.001] compared with healthy controls. Serial measurements revealed that these three analytes dropped statistically significantly from baseline level during remission and were high during exacerbation. Great decline of sTNF-R1 levels was found during remission, with 6.7-fold lower levels than in healthy controls [p = 0.015]. Patients who did not respond to initial prednisone treatment had higher baseline levels of sTNF-R2 [p = 0.001]. Patients experiencing relapses during follow-up had lower baseline sTNF-R2 and VCAM levels compared with patients with long-lasting remission.

CONCLUSIONS

In a large cohort of newly diagnosed untreated CD patients, we identified candidate serum markers [sTNF-R1, sTNF-R2, sIL-2R, and MMP-1] associated with disease activity. Furthermore, sTNF-R2 was associated with prednisone response and, together with VCAM, with long-lasting remission.

Elevated Plasma Levels of sIL-2R in Complex Regional Pain Syndrome: A Pathogenic Role for T-Lymphocytes?

The immune system has long been thought to be involved in the pathophysiology of complex regional pain syndrome (CRPS). However, not much is known about the role of the immune system and specifically T-cells in the onset and maintenance of this disease. In this study, we aimed to evaluate T-cell activity in CRPS by comparing blood soluble interleukin-2 receptor (sIL-2R) levels between CRPS patients and healthy controls. CRPS patients had statistically significant elevated levels of sIL-2R as compared to healthy controls (median sIL-2R levels: 4151 pg/ml (Q3 − Q1 = 5731 pg/ml − 3546 pg/ml) versus 1907 pg/ml (Q3 − Q1: 2206 pg/ml − 1374 pg/ml), p < 0.001, resp.). Furthermore, sIL-2R level seems to be a good discriminator between CRPS patients and healthy controls with a high sensitivity (90%) and specificity (89.5%). Our finding indicates increased T-cell activity in patients with CRPS. This finding is of considerable relevance as it could point towards a T-cell-mediated inflammatory process in this disease. This could pave the way for new anti-inflammatory therapies in the treatment of CRPS. Furthermore, sIL-2R could be a promising new marker for determining inflammatory disease activity in CRPS.

Clinical utility of soluble interleukin-2 receptor in hemophagocytic syndromes: a systematic scoping review

The serum-soluble interleukin-2 receptor (sIL-2r) level is considered an important diagnostic test and disease marker in hemophagocytic syndromes/hemophagocytic lymphohistiocytosis (HPS/HLH). However, this cytokine receptor is rarely measured in clinical practice and has been excluded from recent diagnostic/classification criteria such as the HScore and macrophage activation syndrome (MAS) 16. We performed a systematic scoping review of 64 articles (1975-2016) examining the clinical utility of sIL-2r in HPS/HLH. Twenty-two articles describe sIL-2r as a sensitive diagnostic marker for HLH, but only three distinct datasets actually address sensitivity. The original HLH-2004 Guidelines reported sensitivity of 93% and specificity of 100% for sIL-2r ≥ 2400, based on a pediatric dataset (n = 152) which is published for the first time in this review. Two pediatric studies reported sensitivity of 89% for sIL-2r ≥ 2400 in diagnosis of MAS complicating juvenile idiopathic arthritis (JIA) (n = 27) and 88% for secondary HLH in acute liver failure (n = 9). Twenty articles described sIL-2r as a dynamic marker of disease activity that falls with response to treatment, and 15 described high initial sIL-2r levels >10,000 U/mL as a poor prognostic marker. The ability of sIL-2r to distinguish between subtypes of HPS/HLH was inconsistent. This review confirms the importance of soluble IL-2r as a diagnostic and disease marker in HPS/HLH, but also reveals the need for more primary data about its performance characteristics, particularly in adults. More emphasis should be made in including this simple, inexpensive test in clinical practice and studies of HPS/HLH.

Host factors associated with serologic inflammatory markers assessed using multiplex assays

Chronic systemic inflammation contributes to the development of adverse health conditions, yet the influence of fixed and modifiable risk factors on many serologic biomarkers of inflammation remains largely unknown. Serum concentrations of twenty-three biomarkers, including C-reactive protein (CRP), cytokines (CXCL11, CXCL8, CXCL10, CCL2, CCL13, CCL4, CCL17, CXCL13, IL-10, IL-12p70, IL-6, TNF-α, IL-2, IFN-γ, IL-1β, GM-CSF, BAFF), and soluble immune receptors (sCD14, sIL-2Rα, sCD27, sgp130, sTNF-R2) were measured longitudinally using multiplexed immunometric assays in 250 HIV-uninfected men followed in the Multicenter AIDS Cohort Study (1984-2009). Generalized gamma regression was used to determine the statistical significance of factors associated with each biomarker. After accounting for age, race, and education, and for analysis of multiple biomarkers, higher concentrations of specific individual biomarkers were significantly (P<0.002) associated with hypertension, obesity, hepatitis C infection, stimulant use, and diabetes and lower concentrations with hypercholesterolemia. These associations should be taken into account in epidemiological studies of these biomarkers, and may provide potential targets for disease prevention and treatment.

Prognostic value of blood-biomarkers related to hypoxia, inflammation, immune response and tumour load in non-small cell lung cancer - A survival model with external validation

AIM

Improve the prognostic prediction of clinical variables for non-small cell lung cancer (NSCLC), by selecting from blood-biomarkers, non-invasively describing hypoxia, inflammation and tumour load.

METHODS

Model development and validation included 182 and 181 inoperable stage I-IIIB NSCLC patients treated radically with radiotherapy (55.2%) or chemo-radiotherapy (44.8%). Least absolute shrinkage and selection operator (LASSO), selected from blood-biomarkers related to hypoxia [osteopontin (OPN) and carbonic anhydrase IX (CA-IX)], inflammation [interleukin-6 (IL-6), IL-8, and C-reactive protein (CRP)], and tumour load [carcinoembryonic antigen (CEA), and cytokeratin fragment 21-1 (Cyfra 21-1)]. Sequent model extension selected from alpha-2-macroglobulin (α2M), serum interleukin-2 receptor (sIL2r), toll-like receptor 4 (TLR4), and vascular endothelial growth factor (VEGF). Discrimination was reported by concordance-index.

RESULTS

OPN and Cyfra 21-1 (hazard ratios of 3.3 and 1.7) significantly improved a clinical model comprising gender, World Health Organization performance-status, forced expiratory volume in 1s, number of positive lymph node stations, and gross tumour volume, from a concordance-index of 0.66 to 0.70 (validation=0.62 and 0.66). Extension of the validated model yielded a concordance-index of 0.67, including α2M, sIL2r and VEGF (hazard ratios of 4.6, 3.1, and 1.4).

CONCLUSION

Improvement of a clinical model including hypoxia and tumour load blood-biomarkers was validated. New immunological markers were associated with overall survival. Data and models can be found at www.cancerdata.org (http://dx.doi.org/10.17195/candat.2016.04.1) and www.predictcancer.org.

Pro-Inflammatory Cytokines Predict Relapse-Free Survival after One Month of Interferon-α but Not Observation in Intermediate Risk Melanoma Patients

Background

E1697 was a phase III trial of adjuvant interferon (IFN)-α2b for one month (Arm B) versus observation (Arm A) in patients with resected melanoma at intermediate risk. We evaluated the levels of candidate serum cytokines, the HLA genotype, polymorphisms of CTLA4 and FOXP3 genes and the development of autoantibodies for their association with relapse free survival (RFS) in Arm A and Arm B among 268 patients with banked biospecimens.

Methods

ELISA was used to test 5 autoantibodies. Luminex/One Lambda LABTypeRSSO was used for HLA Genotyping. Selected CTLA4 and FOXP3 Single nucleotide polymorphisms (SNPs) and microsatellites were tested for by polymerase chain reaction (PCR). Sixteen serum cytokines were tested at baseline and one month by Luminex xMAP multiplex technology. Cox Proportional Hazards model was applied and the Wald test was used to test the marginal association of each individual marker and RFS. We used the Lasso approach to select the markers to be included in a multi-marker Cox Proportional Hazards model. The ability of the resulting models to predict one year RFS was evaluated by the time-dependent ROC curve. The leave-one-out method of cross validation (LOOCV) was used to avoid over-fitting of the data.

Results

In the multi-marker modeling analysis conducted in Arm B, one month serum IL2Rα, IL-12p40 and IFNα levels predicted one year RFS with LOOCV AUC = 82%. Among the three markers selected, IL2Rα and IFNα were the most stable (selected in all the cross validation cycles). The risk score (linear combination of the 3 markers) separated the RFS curves of low and high risk groups well (p = 0.05). This model did not hold for Arm A, indicating a differential marker profile in Arm B linked to the intervention (adjuvant therapy).

Conclusions

Early on-treatment proinflammatory serum markers (IL2Rα, IL-12p40, IFNα) significantly predict RFS in our cohort of patients treated with adjuvant IFN-α2b and warrant further study.

Encapsulating peritoneal sclerosis is associated with T-cell activation

BACKGROUND

Encapsulating peritoneal sclerosis (EPS) is an excessive fibrotic response of the peritoneum that may occur after long-term peritoneal dialysis (PD). The underlying pathophysiology is poorly understood, but involvement of peritoneal inflammatory T helper 1 cells may be pivotal.

METHODS

Soluble interleukin-2 receptor alpha (sCD25) concentration was measured as a marker for T-cell activation in serum and ascites from EPS patients and various control patient groups. Peritoneal biopsies were stained for the presence of T cells, and T cells isolated from ascites of EPS patients were characterized in detail for differentiation status and cytokine expression.

RESULTS

Serum sCD25 concentrations are significantly and specifically increased in EPS patients compared with haemodialysis, PD and predialysis patients. Peritoneal effluent of stable PD patients contains very low levels of sCD25, while sCD25 levels in ascites of EPS patients are high and indicative of local production. In the years preceding the diagnosis of EPS, the serum sCD25 concentrations increased while remaining at stable levels in control PD patients. The peritoneum and ascites of EPS patients showed a significant influx of T cells with relatively increased numbers of CD4(+) T cells. These T cells were fully differentiated and displayed a T helper 1 cell type with a pro-inflammatory cytokine profile.

CONCLUSIONS

Increased serum sCD25 concentrations and peritoneal lymphocytosis in EPS patients indicate the involvement of activated T cells in the pathophysiology of excessive fibrosis.

Role of inflammatory cytokines in peripheral nerve injury

Inflammatory events occurring in the distal part of an injured peripheral nerve have, nowadays, a great resonance. Investigating the timing of action of the several cytokines in the important stages of Wallerian degeneration helps to understand the regenerative process and design pharmacologic intervention that promotes and expedites recovery. The complex and synergistic action of inflammatory cytokines finally promotes axonal regeneration. Cytokines can be divided into pro- and anti-inflammatory cytokines that upregulate and downregulate, respectively, the production of inflammatory mediators. While pro-inflammatory cytokines are expressed in the first phase of Wallerian degeneration and promote the recruitment of macrophages, anti-inflammatory cytokines are expressed after this recruitment and downregulate the production of all cytokines, thus determining the end of the process. In this review, we describe the major inflammatory cytokines involved in Wallerian degeneration and the early phases of nerve regeneration. In particular, we focus on interleukin-1, interleukin-2, interleukin-6, tumor necrosis factor-β, interleukin-10 and transforming growth factor-β.

Elevated soluble IL-2Rα, IL-8, and MIP-1β levels are associated with inferior outcome and are independent of MIPI score in patients with mantle cell lymphoma

Mantle cell lymphoma (MCL) is a unique type of lymphoma with a prognosis intermediate between indolent and aggressive types. The purpose of this study was to study blood cytokine levels in newly diagnosed and relapsed MCL patients with respect to patterns of abnormalities and relationship to the MCL International Prognostic Index (MIPI) score. We analyzed blood levels of 30 cytokines using a multiplex ELISA in 88 patients with newly diagnosed MCL (pre-treatment levels) and 20 with relapsed MCL and compared them with controls without known lymphoma. Elevated cytokine levels were compared with clinical outcome and the MIPI score. In the 88 newly diagnosed MCL patients, we found significantly elevated levels compared with controls of IL-12, IP-10, sIL-2Rα, MIG, IL-1RA, IL-8, MIP-1α, and MIP-1β (all P < 0.05). Of these elevated cytokines, sIL-2Rα, IL-8, MIG, MIP-1α, and MIP-1β were predictive of inferior event-free survival, and sIL-2Rα (HR = 1.94; P = 0.038), IL-8 (HR = 2.17; P = 0.015), and MIP-1β (HR = 2.10; P = 0.016) were independent of MIPI score; only sIL-2Rα (HR = 2.35; P = 0.041) was associated with overall survival after adjustment for MIPI. In the relapsed MCL patient group, the only significantly elevated plasma cytokines that predicted EFS were sIL-2Rα (HR = 2.90; P = 0.04) and IL-8 (HR = 3.75; P = 0.02). Elevated blood levels of sIL-2Rα and the pro-inflammatory cytokines IL-8 and MIP-1β are poor prognostic factors in MCL patients and independent of MIPI score. These factors, if validated, will provide important additions to the MIPI and guide the development of new therapies for patients with elevated levels of these cytokines.

Neutrophil-to-lymphocyte and platelet-to-lymphocyte ratios in patients with endometrial hyperplasia and endometrial cancer

AIM

Neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR) and platelet distribution width (PDW) may indicate the systemic inflammatory response associated with various cancers. We aimed to investigate the relationship between NLR, PLR, PDW and endometrial pathologies including hyperplasia and cancer.

METHODS

In this study, 472 cases who underwent endometrial biopsy were included. Three groups were constituted with respect to biopsy results: group 1, endometrial cancer patients (n = 54); group 2, endometrial hyperplasia patients (n = 152); and group 3, patients with normal biopsy results (n = 281). White blood cell and platelet counts as well as NLR, PLR and PDW recorded from complete blood counts obtained on the same day of biopsy were compared in the three groups.

RESULTS

Endometrial cancer patients were significantly older than the cases in the other two groups (P < 0.001). The NLR in group 1 was significantly higher than group 3 (P = 0.02). However, there was no difference between the three groups with respect to PLR (P = 0.167). PDW was increased in group 1 compared to group 3 (P < 0.001).

CONCLUSION

Results of our study have shown that NLR, PLR and PDW are simple, readily available and robust inflammatory markers that may be used in the management of endometrial pathologies. However, the actual predictive potential of these biomarkers still warrants further trials.

Silica exposure and altered regulation of autoimmunity

Silica particles and asbestos fibers, which are known as typical causatives of pneumoconiosis, induce lung fibrosis. Moreover, silicosis patients often complicate with autoimmune diseases, and asbestos-exposed patients suffer from malignant diseases such as pleural mesothelioma and lung cancer. We have been conducting experimental studies to investigate altered regulation of self-tolerance caused by silica exposure, including analyses using specimens such as plasma and immunocompetent cells obtained from silicosis patients, as a means of examining the supposition that silica exposure induces molecular and cellular biological alterations of immune cells. These approaches have resulted in the detection of several specific autoantibodies, alterations of CD95/Fas and its related molecules, and evidence of chronic activation of responder T cells and regulatory T cells following silica exposure. In this review, we present details of our investigations as an introduction to scientific approaches examining the immunological effects of environmental and occupational substances.