Human Plasma IgG N-Glycome Profiles Reveal a Proinflammatory Phenotype in Chronic Thromboembolic Pulmonary Hypertension

Serum IgG galactosylation as a potential biomarker for the diagnosis of echinococcosis

Echinococcosis is a serious and potentially fatal parasitic zoonosis, which can be divided into two subtypes in humans including cystic echinococcosis (CE) and alveolar echinococcosis (AE). It poses a great threat to patients' lives, making timely diagnosis and subtype discrimination crucial. AE is easily confused with hepatocellular carcinoma (HCC) due to their highly similar features, so differential diagnosis is also imperative. In this work, the galactosylation level of serum IgG was analyzed by Matrix-Assisted Laser Desorption/Ionization Time of Flight Mass Spectrometry (MALDI-TOF-MS) in a cohort comprising patients, including 100 diagnosed with CE, 27 with AE and 29 with HCC. The relative quantification of IgG digalactosylated (G2), monogalactosylated (G1), and agalactosylated (G0) N-glycans with the formula G0/(G1 + G2 × 2) (IgG Gal-ratio) was obtained and found to effectively distinguish between echinococcosis patients, CE and AE patients, and healthy controls, respectively. Meanwhile, the IgG Gal-ratio was evidently related to different types of CE (from CE1 to CE5) and the follow-up CE disease progress. Furthermore, the IgG Gal-ratio shows the potential differential diagnosis of AE and HCC. Thus, the results demonstrate that the IgG Gal-ratio has the potential to be a biomarker for diagnosis and discrimination of echinococcosis, which also needs to be verified in further studies.

Analysis of clinical features and risk factors of pulmonary hypertension associated with interstitial lung disease

Pulmonary hypertension (PH) can significantly impact the prognosis of interstitial lung disease (ILD). There are limited studies on the clinical characteristics and risk factors of PH associated with ILD (PH-ILD). The present study aimed to analyze the clinical characteristics of patients with PH-ILD and explore the correlation and predictive value of the easily obtainable indicators with respect to the severity of PH in patients with ILD. The results indicated that the red blood cell distribution width (RDW) and mean platelet volume (MPV) of patients with ILD with the moderate-to-severe PH (Ms-PH) were significantly higher compared with those of patients with ILD without PH and those with Mild-PH (P<0.05). Age, RDW, MPV and immunoglobulin G levels were emerged as independent risk factors for Ms-PH in patients with ILD. Receiver operating characteristic curve analysis demonstrated that the combination of RDW and MPV enhances the diagnostic efficiency for Ms-PH in patients with ILD. Consequently, the present study demonstrated that RDW and MPV are predictive factors for Ms-PH in patients with ILD.

Immunoglobulin G N-Glycome as a biomarker of mortality risk in Escherichia coli induced sepsis

Background

Sepsis is a life-threatening syndrome caused by an imbalance in the inflammatory response to an infection that can lead to a high mortality rate. Escherichia coli is a common pathogen that causes sepsis. The role of immunoglobulin G N-glycome in estimating the mortality in patients with sepsis remains unknown. This study aims to reveal the clinical application of immunoglobulin G N-glycome as a potentially novel biomarker to predict mortality risk in Escherichia coli-induced sepsis.

Methods

The serum immunoglobulin G N-glycome levels in 100 adult septic patient serum samples on the day of intensive care unit (ICU) admission, and 100 healthy volunteers were measured and analyzed. Immunoglobulin G N-glycome was compared with existing risk scores on predicting in-hospital death.

Results

We identified that the fucosylation level was significantly decreased in patients. Importantly, bisecting GlcNAc, sialylation, and galactosylation have different levels between sepsis and control groups. In addition, the AUC values of the SOFA score combined with GP4, GP5, and GP9 were 0.76 (95%CI: 0.61 to 0.90), 0.58 (95%CI: 0.40 to 0.7) and 0.57 (95%CI: 0.38 to 0.76). The AUC value of the SOFA score combined with GP4 and GP7 was 0.85 (95%CI: 0.76 to 0.93) in predicting in-hospital mortality in patients with sepsis.

Conclusions

Immunoglobulin G N-glycome concentrations at ICU admission are valuable for predicting the in-hospital mortality risk of patients with sepsis, suggesting that immunoglobulin G N-glycome may be a novel biomarker.

Immuno-inflammatory mechanisms in cardio-oncology: new hopes for immunotargeted therapies

Cardio-oncology is an emerging interdisciplinary field concerned with cancer treatment-related cardiovascular toxicities (CTR-CVT) and concomitant cardiovascular diseases (CVD) in patients with cancer. Inflammation and immune system dysregulation are common features of tumors and cardiovascular disease (CVD). In addition to the mutual exacerbating effect through inflammation, tumor treatments, including immunotherapy, chemotherapy, radiation therapy, and targeted therapy, may induce immune inflammatory reactions leading to cardiovascular damage. Cancer immunotherapy is currently a new method of cancer treatment. Immunotherapeutic agents, such as immune checkpoint inhibitors (ICIs), chimeric antigen receptor T cell immunotherapy (CAR-T), mRNA vaccines, etc., can induce anti-tumor effects by enhancing the host immune response to eliminate tumor cells. They have achieved remarkable therapeutic efficacy in clinical settings but lead to many immune-related adverse events (irAEs), especially CTR-CVT. Establishing specific evaluation, diagnostic, and monitoring criteria (e.g., inflammatory biomarkers) for both immunotherapy and anti-inflammatory therapy-related cardiovascular toxicity is vital to guide clinical practice. This article explores the role of immune response and inflammation in tumor cardiology, unravels the underlying mechanisms, and provides improved methods for monitoring and treating in CTR-CVT in the field of cardio-oncology.

Crosstalk Between Cytokines and IgG N-Glycosylation: Bidirectional Effects and Relevance to Clinical Innovation for Inflammatory Diseases

The crosstalk between cytokines and immunoglobulin G (IgG) N-glycosylation forms a bidirectional regulatory network that significantly impacts inflammation and immune function. This review examines how various cytokines, both pro- and anti-inflammatory, modulate IgG N-glycosylation, shaping antibody activity and influencing inflammatory responses. In addition, we explore how altered IgG N-glycosylation patterns affect cytokine production and immune signaling, either promoting or reducing inflammation. Through a comprehensive analysis of current studies, this review underscores the dynamic relationship between cytokines and IgG N-glycosylation. These insights enhance our understanding of the mechanisms underlying inflammatory diseases and contribute to improved strategies for disease prevention, diagnosis, monitoring, prognosis, and the exploration of novel treatment options. By focusing on this crosstalk, we identify new avenues for developing innovative diagnostic tools and therapies to improve patient outcomes in inflammatory diseases.

Human IgG Subclasses Differ in the Structural Elements of Their N-Glycosylation

Although immunoglobulin G (IgG) harbors just one N-glycosylation site per heavy chain, this glycosylation plays a key role in modulating its function. In human serum, IgG is classified into four subclasses (IgG1, IgG2, IgG3, IgG4), each characterized by unique features in their sequences, disulfide bridges and glycosylation signatures. While protein glycosylation is typically studied at the compositional level, this severely underestimates the complexity of the molecules involved. Glycan functionality heavily relies on the precise linkages and branching between monosaccharides, yet these features are challenging to study. Here, by development of a nanohydrophilic interaction chromatography (HILIC)-LC-MS/MS method, we reveal distinct structural glycosylation signatures for each of the four IgG subclasses, namely that IgG1 and IgG3 display predominant galactosylation of the 6-branched antenna, IgG2 instead of the 3-branched antenna, while IgG4 displays a balance. These and other subclass-specific glycostructural elements proved observable in both recombinant and endogenous IgGs as present in human plasma, in which interindividual differences and temporal stability could be demonstrated. Structural glycoproteomics is expected to fundamentally alter the way in which we study IgG, opening up a new layer of functional investigation and biomarker development, while also revealing new key structural differences between recombinant IgG subclasses in therapeutic applications.

Prognostic Value of Plasma Immunoglobulin G N-Glycome Traits in Pulmonary Arterial Hypertension

BACKGROUND

B-type natriuretic peptide or N-terminal pro-B-type natriuretic peptide is the only blood biomarker in established risk calculators for pulmonary arterial hypertension (PAH). Profiling systemic-originated plasma immunoglobulin G (IgG) N-glycans, which reflect different components of the pathophysiology of PAH including immune dysregulation and inflammation, may improve PAH risk assessment.

OBJECTIVES

This study sought to identify plasma IgG N-glycan biomarkers that predict survival in PAH to improve risk assessment.

METHODS

This cohort study examined 622 PAH patients from 2 national centers (Beijing [discovery] cohort: n = 273; Shanghai [validation] cohort: n = 349). Plasma IgG N-glycomes were profiled by a robust mass spectrometry-based method. Prognostic IgG N-glycan traits were identified and validated in the 2 cohorts using Cox regression and Kaplan-Meier survival analyses. The added value of IgG N-glycan traits to previously established risk models was assessed using Harrell C-indexes and survival analysis.

RESULTS

Plasma IgG fucosylation was found to predict survival independent of age and sex in the discovery cohort (HR: 0.377; 95% CI: 0.168-0.845; P = 0.018) with confirmation in the validation cohort (HR: 0.445; 95% CI: 0.264-0.751; P = 0.005). IgG fucosylation remained a robust predictor of mortality in combined cohorts after full adjustment and in subgroup analyses. Integrating IgG fucosylation into previously established risk models improved their predictive capacity, marked by an overall elevation in Harrell C-indexes. IgG fucosylation was useful in further stratifying the intermediate-risk patients classified by a previously established model.

CONCLUSIONS

Plasma IgG fucosylation informs PAH prognosis independent of established factors, offering additional value for predicting PAH outcomes.

Glycosylation: mechanisms, biological functions and clinical implications

Protein post-translational modification (PTM) is a covalent process that occurs in proteins during or after translation through the addition or removal of one or more functional groups, and has a profound effect on protein function. Glycosylation is one of the most common PTMs, in which polysaccharides are transferred to specific amino acid residues in proteins by glycosyltransferases. A growing body of evidence suggests that glycosylation is essential for the unfolding of various functional activities in organisms, such as playing a key role in the regulation of protein function, cell adhesion and immune escape. Aberrant glycosylation is also closely associated with the development of various diseases. Abnormal glycosylation patterns are closely linked to the emergence of various health conditions, including cancer, inflammation, autoimmune disorders, and several other diseases. However, the underlying composition and structure of the glycosylated residues have not been determined. It is imperative to fully understand the internal structure and differential expression of glycosylation, and to incorporate advanced detection technologies to keep the knowledge advancing. Investigations on the clinical applications of glycosylation focused on sensitive and promising biomarkers, development of more effective small molecule targeted drugs and emerging vaccines. These studies provide a new area for novel therapeutic strategies based on glycosylation.

Influence of plasma collection tubes on N-glycome in human blood samples

Background and aims

Quantitative analysis of plasma N-glycome is a promising method for identifying disease biomarkers. This study aimed to investigate the impact of using blood collection tubes with different anticoagulants on plasma N-glycome.

Materials and methods

We used a robust mass spectrometry method to profile plasma N-glycomes in two cohorts of healthy volunteers (cohort 1, n = 16; cohort 2, n = 53). The influence of three commonly used blood collection tubes on fully characterized N-glycomic profiles were explored.

Results

Principal component analysis revealed distinct clustering of blood samples based on the collection tubes. Pairwise comparisons demonstrated significant differences between EDTA and heparin plasma in 55 out of 82 quantified N-glycan traits, and between EDTA and citrate plasma in 62 out of 82 traits. These differences encompassed various N-glycan features, including glycan type, sialylation, galactosylation, fucosylation, and bisection. Trends in N-glycan variations in citrate and heparin plasma were largely consistent compared to EDTA plasma. In correlation analysis (EDTA vs. heparin; EDTA vs. citrate), Pearson's correlation coefficients were consistently higher than 0.7 for the majority of N-glycan traits.

Conclusion

Sample matrix variations impact plasma N-glycome measurements. Caution is crucial when comparing samples from different plasma collection tubes in glycomics projects.

Clonal Hematopoiesis of Indeterminate Potential in Chronic Thromboembolic Pulmonary Hypertension: A Multicenter Study

BACKGROUND

The pathogenesis of chronic thromboembolic pulmonary hypertension (CTEPH) is multifactorial and growing evidence has indicated that hematological disorders are involved. Clonal hematopoiesis of indeterminate potential (CHIP) has recently been associated with an increased risk of both hematological malignancies and cardiovascular diseases. However, the prevalence and clinical relevance of CHIP in patients with CTEPH remains unclear.

METHODS

Using stepwise calling on next-generation sequencing data from 499 patients with CTEPH referred to 3 centers between October 2006 and December 2021, CHIP mutations were identified. We associated CHIP with all-cause mortality in patients with CTEPH. To provide insights into potential mechanisms, the associations between CHIP and inflammatory markers were also determined.

RESULTS

In total, 47 (9.4%) patients with CTEPH carried at least 1 CHIP mutation at a variant allele frequency of ≥2%. The most common mutations were in DNMT3A, TET2, RUNX1, and ASXL1. During follow-up (mean, 55 months), deaths occurred in 22 (46.8%) and 104 (23.0%) patients in the CHIP and non-CHIP groups, respectively (P<0.001, log-rank test). The association of CHIP with mortality remained robust in the fully adjusted model (hazard ratio, 2.190 [95% CI, 1.257-3.816]; P=0.006). Moreover, patients with CHIP mutations showed higher circulating interleukin-1β and interleukin-6 and lower interleukin-4 and IgG galactosylation levels.

CONCLUSIONS

This is the first study to show that CHIP mutations occurred in 9.4% of patients with CTEPH are associated with a severe inflammatory state and confer a poorer prognosis in long-term follow-up.