Hypogammaglobulinemia and Risk of Exacerbation and Mortality in Patients with COPD

Serum Immunoglobulin G Levels Are Associated with Risk for Exacerbations: An Analysis of SPIROMICS

Rationale: Serum IgG deficiency is associated with morbidity in chronic obstructive pulmonary disease (COPD), but it is unclear whether concentrations in the lower end of the normal range still confer risk. Objectives: To determine if levels above traditional cutoffs for serum IgG deficiency are associated with exacerbations among current and former smokers with or at risk for COPD. Methods: Former and current smokers in SPIROMICS (the Subpopulations and Intermediate Outcome Measures of COPD study) (n = 1,497) were studied: 1,026 with COPD and 471 at risk for COPD. In a subset (n = 1,031), IgG subclasses were measured. Associations between total IgG or subclasses and prospective exacerbations were evaluated with multivariable models adjusting for demographic characteristics, current smoking, smoking history, FEV1 percent predicted, inhaled corticosteroids, and serum IgA. Measurements and Main Results: The 35th percentile (1,225 mg/dl in this cohort) of IgG was the best cutoff by Akaike information criterion. Below this, there was increased exacerbation risk (incidence rate ratio [IRR], 1.28; 95% confidence interval [CI], 1.08-1.51). Among subclasses, IgG1 and IgG2 below the 35th percentile (354 and 105 mg/dl, respectively) were associated with increased risks of severe exacerbation (IgG1, IRR, 1.39; 95% CI, 1.06-1.84; IgG2, IRR, 1.50; 95% CI, 1.14-1.1.97). These associations remained significant when additionally adjusting for a history of exacerbations. Conclusions: Lower serum IgG is prospectively associated with exacerbations in individuals with or at risk for COPD. Among subclasses, lower IgG1 and IgG2 are prospectively associated with severe exacerbations. The optimal IgG cutoff was substantially higher than traditional cutoffs for deficiency, suggesting that subtle impairment of humoral immunity may be associated with exacerbations.

A Pilot Study on Proteomic Predictors of Mortality in Stable COPD

Chronic Obstructive Pulmonary Disease (COPD) is the third leading cause of global mortality. Despite clinical predictors (age, severity, comorbidities, etc.) being established, proteomics offers comprehensive biological profiling to obtain deeper insights into COPD pathophysiology and survival prognoses. This pilot study aimed to identify proteomic footprints that could be potentially useful in predicting mortality in stable COPD patients. Plasma samples from 40 patients were subjected to both blind (liquid chromatography-mass spectrometry) and hypothesis-driven (multiplex immunoassays) proteomic analyses supported by artificial intelligence (AI) before a 4-year clinical follow-up. Among the 34 patients whose survival status was confirmed (mean age 69 ± 9 years, 29.5% women, FEV1 42 ± 15.3% ref.), 32% were dead in the fourth year. The analysis identified 363 proteins/peptides, with 31 showing significant differences between the survivors and non-survivors. These proteins predominantly belonged to different aspects of the immune response (12 proteins), hemostasis (9), and proinflammatory cytokines (5). The predictive modeling achieved excellent accuracy for mortality (90%) but a weaker performance for days of survival (Q2 0.18), improving mildly with AI-mediated blind selection of proteins (accuracy of 95%, Q2 of 0.52). Further stratification by protein groups highlighted the predictive value for mortality of either hemostasis or pro-inflammatory markers alone (accuracies of 95 and 89%, respectively). Therefore, stable COPD patients' proteomic footprints can effectively forecast 4-year mortality, emphasizing the role of inflammatory, immune, and cardiovascular events. Future applications may enhance the prognostic precision and guide preventive interventions.

Serum immunoglobulin levels in group E of chronic obstructive pulmonary disease: insights for clinical management and immunoglobulin therapy strategies

OBJECTIVE

The study aimed to characterize serum immunoglobulin (Ig) concentrations and their relationship with clinical and paraclinical features in patients with COPD group E in the stable stage. Additionally, the study focused on evaluating the relationship between serum Ig levels and the risk of exacerbations over the next 12 months, thereby clarifying the role of serum Ig deficiency in affecting the future risk for these patients.

METHODS

A prospective observational study assessed IgG, IgA, IgM, and IgE levels in 67 COPD patients and 30 healthy controls at Military Hospital 103 from October 2017 to August 2020. Primary outcomes included Ig isotype levels in COPD patients, with secondary outcomes exploring differences compared to controls and associations with clinical variables.

RESULTS

COPD patients showed significantly lower IgG concentrations and higher IgA levels than controls. IgM and IgE levels did not differ significantly. Subgroup analysis revealed notable decreases in IgG1 and IgG3 concentrations, with 10.4% of patients exhibiting reduced IgG levels and 0.3% diagnosed with common variable immunodeficiency. No significant associations were found between Ig levels and exacerbation risk or clinical variables.

CONCLUSIONS

Serum IgG and IgM concentrations were significantly reduced in COPD patients compared to normal individuals, with IgG1 and IgG3 concentrations notably low. Serum IgA levels were significantly higher in COPD patients compared with normal controls. However, no significant association was found between Ig concentrations, particularly serum IgG deficiency and its subclasses, with the frequency and risk of exacerbations during 12 months of longitudinal follow-up. Caution is warranted in the use of immunoglobulin therapy in the treatment of COPD patients.

TRIAL REGISTRATION

An independent ethics committee approved the study (Ethics Committee of Military Hospital 103 (No. 57/2014/VMMU-IRB), which was performed in accordance with the Declaration of Helsinki, Guidelines for Good Clinical Practice.

Expert panel opinion on adult pneumococcal vaccination in the post-COVID era (NAP- EXPO Recommendations-2024)

INTRODUCTION

Pneumococcal diseases pose a significant public health concern in India, with substantial morbidity and mortality, with the elderly and those with coexisting medical conditions being most at risk. Pneumococcus was also seen to be one of the main reasons for co-infection, pneumonia and complications in COVID. Current guidelines recommend vaccination for specific adult populations, but there is a lack of uniformity and guidance on risk stratification, prioritisation and optimal timing.

METHODS

Nation Against Pneumococcal Infections - Expert Panel Opinion (NAP-EXPO) is a panel convened to review and update recommendations for adult pneumococcal vaccination in India. The panel of 23 experts from various medical specialties engaged in discussions and evidence-based reviews, discussed appropriate age for vaccination, risk stratification for COPD and asthma patients, vaccination strategies for post-COVID patients, smokers and diabetics, as well as methods to improve vaccine awareness and uptake.

OUTCOME

The NAP-EXPO recommends the following for adults: All healthy individuals 60 years of age and above should receive the pneumococcal vaccine; all COPD patients, regardless of severity, high-risk asthma patients, post-COVID cases with lung fibrosis or significant lung damage, should be vaccinated with the pneumococcal vaccine; all current smokers and passive smokers should be educated and offered the pneumococcal vaccine, regardless of their age or health condition; all diabetic individuals should receive the pneumococcal vaccine, irrespective of their diabetes control. Strategies to improve vaccine awareness and uptake should involve general practitioners (GPs), primary health physicians (PHPs) and physicians treating patients at high risk of pneumococcal disease. Advocacy campaigns should involve media, including social media platforms.

CONCLUSION

These recommendations aim to enhance pneumococcal vaccination coverage among high-risk populations in India in order to ensure a reduction in the burden of pneumococcal diseases, in the post-COVID era. There is a need to create more evidence and data to support the recommendations that the vaccine will be useful to a wider range of populations, as suggested in our consensus.

Effectiveness of immunoglobulin replacement therapy in preventing infections in patients with chronic obstructive pulmonary disease: a systematic review

PURPOSE

Immunoglobulin replacement therapy is a standard treatment for patients with antibody production deficiencies, which is of interest in patients with chronic obstructive pulmonary disease (COPD). This systematic review, registered with PROSPERO (CRD42021281118), assessed the current literature regarding immunoglobulin replacement therapy on COPD clinical outcomes in patients with low immunoglobulin G (IgG) serum concentrations.

METHODS

Literature searches conducted from inception to August 23, 2021, in databases including MEDLINE, EMBASE, and CINAHL. Population (sex, age, comorbidities), baseline clinical characteristics (pulmonary function testing results, IgG levels), and outcome (hospitalizations, emergency department visits) were extracted after title/abstract and full text screening. The Cochrane risk of bias assessment form was used for risk of bias assessment of randomized controlled trials and the National Heart, Lung, and Blood Institute (NHLBI) assessment was used for pre and post studies.

RESULTS

A total of 1381 studies were identified in the preliminary search, and 874 records were screened after duplicates were removed. Screening 77 full texts yielded four studies that were included in the review.

CONCLUSION

It is unclear whether immune globulin replacement therapy reduces acute exacerbation frequency and severity in COPD. Current evidence suggests that it is worth considering, but better developed protocols for administration of immune globulin supplementation is required for future randomized controlled trials.

COPD: systemic proteomic profiles in frequent and infrequent exacerbators

Background

Some patients with COPD suffer frequent exacerbations (FE). We hypothesised that their systemic proteomic profile would be different from that of non-frequent exacerbators (NFE). The objective of the present study was to contrast the systemic proteomic profile in FE versus NFE. As a reference, we also determined the systemic proteomic profile of healthy controls (HC) and COPD patients during an actual episode of exacerbation (AE).

Methods

In the analysis we included 40 clinically stable COPD patients (20 FE and 20 NFE), and 20 HC and 10 AE patients. Their plasma samples were analysed by combining two complementary proteomic approaches: label-free liquid chromatography-tandem mass spectrometry and multiplex immunoassays. Gene Ontology annotation, pathway enrichment and network analyses were used to investigate molecular pathways associated with differentially abundant proteins/peptides (DAPs).

Results

Compared with HC, we identified 40 DAPs in FE, 10 in NFE and 63 in AE. Also compared to HC, pathway functional and protein-protein network analyses revealed dysregulation of inflammatory responses involving innate and antibody-mediated immunity in COPD, particularly in the FE group, as well as during an AE episode. Besides, we only identified alterations in the complement and coagulation cascades in AE.

Conclusion

There are specific plasma proteome profiles associated with FE, which are partially shared with findings observed during AE, albeit others are uniquely present during the actual episode of AE.

Low immunoglobulin levels affect the course of COPD in hospitalized patients

BACKGROUND

Chronic obstructive pulmonary disease (COPD) affects up to 10% of Canadians. Patients with COPD may present with secondary humoral immunodeficiency as a result of chronic disease, poor nutrition or frequent courses of oral corticosteroids; decreased humoral immunity may predispose these patients to mucosal infections. We hypothesized that decreased serum immunoglobulin (Ig) levels was associated with the severity of an acute COPD exacerbations (AECOPD).

METHODS

A prospective study to examine cardiovascular risks in patients hospitalized for AECOPD, recruited patients on the day of hospital admission and collected data on length of hospital stay at index admission, subsequent emergency department visits and hospital readmissions. Immunoglobulin levels were measured in serum collected prospectively at recruitment.

RESULTS

Among the 51 patients recruited during an admission for AECOPD, 14 (27.5%) had low IgG, 1 (2.0%) low IgA and 16 (31.4%) low IgM; in total, 24 (47.1%) had at least one immunoglobulin below the normal range. Patients with low IgM had longer hospital stay during the index admission compared to patients with normal IgM levels (6.0 vs. 3.0 days, p = 0.003), but no difference in other clinical outcomes. In the whole cohort, there was a negative correlation between serum IgM levels and length of hospital stay (R = - 0.317, p = 0.024). There was no difference in clinical outcomes between subjects with normal and low IgG levels.

CONCLUSION

In patients presenting with AECOPD, low IgM is associated with longer hospital stay and may indicate a patient phenotype that would benefit from efforts to prevent respiratory infections. Trial registration statement: Retrospectively registered.

Changes in Serum Immunoglobulin G Subclasses during the Treatment of Patients with Chronic Obstructive Pulmonary Disease with Infectious Exacerbations

Introduction: Despite the theoretical importance of serum immunoglobulin (Ig) in the outcome of COPD exacerbations, the existing evidence for this has not been enough. This study was performed to evaluate changes in serum Ig levels and their relationship with outcomes of acute infectious exacerbations in patients with COPD. Methods: The prospective study was conducted at Military Hospital 103 from August 2017 to April 2019. Group D patients with COPD with infectious exacerbation were selected for participation in the study. The control group consisted of 30 healthy people. The patients were provided clinical examination and laboratory service; simultaneously, we measured their serum Ig levels (total IgG, IgG1, IgG2, IgG3, IgG4) at two time points: at admission (T1) and the final health outcome (T2). Results: The median levels of total IgG in patients at times T1 and T2 were significantly lower compared with those in the healthy group (1119.3 mg/dL and 1150.6 mg/dL compared with 2032.2 mg/dL) (p < 0.001). Regarding changes among IgG subclasses, the IgG1, IgG3, and IgG4 levels measured at T1 and T2 were reduced significantly compared with the control group (p < 0.05); the IgG3 levels at T1 were significantly higher than those at T2. IgG3 levels in patients with life-threatening exacerbations were significantly lower than the remaining ones (24.6 (26.8−155.5) mg/dL and 25.6 (29.5−161.2) mg/dL, respectively, p = 0.023). Conclusions: In group D patients with COPD with infectious exacerbations, there was a decrease in the serum IgG, IgG1, IgG3, and IgG4 levels. IgG3 levels were associated with the severity of COPD exacerbation.

The impact of IgG subclass deficiency on the risk of mortality in hospitalized patients with COPD

Background

Immunoglobulin G (IgG) deficiency increases the risk of acute exacerbations and mortality in chronic obstructive pulmonary disease (COPD). However, the impact of IgG subclass deficiency on mortality in COPD is unknown. Here, we determined which IgG subclass, if any, is associated with increased risk of mortality in COPD.

Methods

We measured serum IgG subclass concentrations of 489 hospitalized patients with COPD who were enrolled in the Rapid Transition Program (clinicaltrials.gov identifier NCT02050022). To evaluate the impact of IgG subclass deficiency on 1-year mortality, Cox proportional hazards regression analyses were performed with adjustments for potential confounders.

Results

Deficiencies in IgG1, IgG2, IgG3, and IgG4 were present in 1.8%, 12.1%, 4.3%, and 11.2% of patients, respectively. One-year mortality was 56% in patients with IgG1 deficiency, 27% in IgG2 deficiency, 24% in IgG3 deficiency, and 31% in IgG4 deficiency. Cox proportional modeling showed that IgG1 and IgG4 deficiencies increased the 1-year mortality risk with an adjusted hazard ratio of 3.92 (95% confidence interval [CI] = 1.55–9.87) and 1.74 (95% CI = 1.02–2.98), respectively. Neither IgG2 nor IgG3 deficiency significantly increased 1-year mortality. Two or more IgG subclass deficiencies were observed in 5.3%. Patients with 2 or more IgG subclass deficiencies had a higher 1-year mortality than those without any deficiencies (46.2% vs. 19.7%, p < 0.001), with an adjusted hazard ratio of 2.22 (95% CI = 1.18–4.17).

Conclusions

IgG1 and IgG4 deficiency was observed in 1.8% and 11.2% of hospitalized patients with COPD, respectively, and these deficiencies were associated with a significantly increased risk of 1-year mortality.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12931-022-02052-3.

Prediction of Acute COPD Exacerbation in the Swiss Multicenter COPD Cohort Study (TOPDOCS) by Clinical Parameters, Medication Use, and Immunological Biomarkers

BACKGROUND AND OBJECTIVE

Whether immunological biomarkers combined with clinical characteristics measured during an exacerbation-free period are predictive of acute exacerbation of chronic obstructive pulmonary disease (AECOPD) frequency and severity is unknown.

METHOD

We measured immunological biomarkers and clinical characteristics in 271 stable chronic obstructive pulmonary disease (COPD) patients (67% male, mean age 63 years) from "The Obstructive Pulmonary Disease Outcomes Cohort of Switzerland" cohort on a single occasion. One-year follow-up data were available for 178 patients. Variables independently associated with AECOPD frequency and severity were identified by multivariable regression analyses. Receiver operating characteristic analysis was used to obtain optimal cutoff levels and measure the area under the curve (AUC) in order to assess if baseline data can be used to predict future AECOPD.

RESULTS

Higher number of COPD medications (adjusted incident rate ratio [aIRR] 1.17) and platelet count (aIRR 1.03), and lower FEV1% predicted (aIRR 0.84) and IgG2 (aIRR 0.84) were independently associated with AECOPD frequency in the year before baseline. Optimal cutoff levels for experiencing frequent (>1) AECOPD were ≥3 COPD medications (AUC = 0.72), FEV1 ≤40% predicted (AUC = 0.72), and IgG2 ≤2.6 g/L (AUC = 0.64). The performance of a model using clinical and biomarker parameters to predict future, frequent AECOPD events in the same patients was fair (AUC = 0.78) but not superior to a model using only clinical parameters (AUC = 0.79). The IFN-lambda rs8099917GG-genotype was more prevalent in patients who had severe AECOPD.

CONCLUSIONS

Clinical and biomarker parameters assessed at a single point in time correlated with the frequency of AECOPD events during the year before and the year after assessment. However, only clinical parameters had fair discriminatory power in identifying patients likely to experience frequent AECOPD.

Association of mannose-binding lectin, ficolin-2 and immunoglobulin concentrations with future exacerbations in patients with chronic obstructive pulmonary disease: secondary analysis of the randomized controlled REDUCE trial

BACKGROUND

The innate and adaptive immune system is involved in the airway inflammation associated with acute exacerbations in patients with chronic obstructive pulmonary disease (COPD). We evaluated the association of mannose-binding lectin (MBL), immunoglobulin (Ig) and ficolin-2 concentrations with COPD exacerbations and according to the glucocorticoid treatment duration for an index exacerbation.

METHODS

Post-hoc analysis of the randomized, double-blind, placebo-controlled REDUCE trial of 5 vs. 14 days of glucocorticoid treatment for an index exacerbation. MBL, ficolin-2 and total IgG/IgA and subclass concentrations were determined in stored samples drawn (n = 178) 30 days after the index exacerbation and associated with the risk of re-exacerbation during a 180-day follow-up period.

RESULTS

IgG and subclass concentrations were significantly lower after 14 days vs. 5 days of glucocorticoid treatment. Patients with higher MBL concentrations were more likely to suffer from a future exacerbation (multivariable hazard ratio 1.03 per 200 ng/ml increase (95% confidence interval (CI) 1.00-1.06), p = 0.048), whereas ficolin-2 and IgG deficiency were not associated. The risk was most pronounced in patients with high MBL concentrations, IgG deficiency and 14 days of glucocorticoid treatment pointing towards an interactive effect of MBL and IgG deficiency in the presence of prolonged glucocorticoid treatment duration [Relative excess risk due to interaction 2.13 (95% CI - 0.41-4.66, p = 0.10)]. IgG concentrations were significantly lower in patients with frequent re-exacerbations (IgG, 7.81 g/L vs. 9.53 g/L, p = 0.03).

CONCLUSIONS

MBL modified the short-term exacerbation risk after a recent acute exacerbation of COPD, particularly in the setting of concurrent IgG deficiency and recent prolonged systemic glucocorticoid treatment. Ficolin-2 did not emerge as a predictor of a future exacerbation risk.

Polyvalent Immunoglobulin as a Potential Treatment Option for Patients with Recurrent COPD Exacerbations

Chronic obstructive pulmonary disease (COPD) is characterized by chronic airway inflammation and episodes of worsening respiratory symptoms and pulmonary function, termed acute exacerbations of COPD (AECOPD). AECOPD episodes are associated with heightened airway inflammation and are often triggered by infection. A subset of COPD patients develops frequent exacerbations despite maximal existing standard medical therapy. It is therefore clear that a targeted and more effective prevention strategy is needed. Immunoglobulins are glycoprotein molecules that are secreted by B lymphocytes and plasma cells and play a critical role in the adaptive immune response against many pathogens. Altered serum immunoglobulin levels have been observed in patients with immunodeficiencies and inflammatory diseases. Serum immunoglobulin has also been identified as potential biomarkers of AECOPD frequency. Since plasma-derived polyvalent immunoglobulin treatment is effective in preventing recurrent infections in immunodeficient patients and in suppressing inflammation in many inflammatory diseases, it may be conceivable that immunoglobulin treatment may be effective in preventing recurrent AECOPD. In this article, we provide a review of the current knowledge on immunoglobulin treatment in patients with COPD and discuss plausible mechanisms as to how immunoglobulin treatment may work to reduce AECOPD frequency.