A Retrospective Longitudinal Within-Subject Risk Interval Analysis of Immunoglobulin Treatment for Recurrent Acute Exacerbation of Chronic Obstructive Pulmonary Disease

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.

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.

Respiratory infectious burden in a cohort of antibody deficiency patients treated with immunoglobulin replacement therapy: The impact of lung pathology and gastroesophageal reflux disease

Background

Antibody deficiencies result from reduced immunoglobulin levels and function, increasing susceptibility to, primarily, bacterial infection. Primary antibody deficiencies comprise intrinsic defects in B-cell physiology, often due to inherited errors. Hematological malignancies or B-cell suppressive therapy are major causes of secondary antibody deficiency. Although immunoglobulin replacement therapy (IGRT) reduces infectious burden in antibody deficiency patients, respiratory tract infections remain a significant health burden. We hypothesize that lung pathology and gastroesophageal reflux disease (GORD) increase the risk of pneumonia in antibody deficiency patients, as in the general population.

Objective

For our cohort of patients with primary antibody deficiency and secondary antibody deficiency, we reviewed their respiratory infectious burden and the impact of lung pathologies and GORD.

Methods

The medical records of 231 patients on IGRT at a tertiary referral center, from October 26, 2014, to February 19, 2021, were reviewed to determine microbial isolates from sputum samples and prevalence of common lung pathologies and GORD.

Results

Haemophilus and Pseudomonas species represent a large infectious burden, being identified in 30.2% and 21.4% of sputum samples demonstrating growth, respectively; filamentous fungal and mycobacterial infections were rare. Diagnosed lung pathology increased the proportion of patients with Pseudomonas, Klebsiella, Stenotrophomonas, and Candida species isolated in their sputum, and diagnosed GORD increased the proportion with Enterobacter and Candida species isolated.

Conclusions

Bacterial respiratory infectious burden remains in primary antibody deficiency and secondary antibody deficiency despite IGRT. Lung pathologies encourage growth of species less susceptible to IGRT, so specialist respiratory medicine input and additional treatments such as inhaled antibiotics are indicated to optimize respiratory outcomes.

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.

Bronchiectasis and obstructive lung diseases in primary antibody deficiencies and beyond: update on management and pathomechanisms

PURPOSE OF REVIEW

Pulmonary complications are among the most frequent manifestations in patients with primary antibody deficiency (PAD), contributing significantly to morbidity and mortality. Here, we focus on recent findings in obstructive pulmonary disease and bronchiectasis in PAD. Since specific data on patients with PAD is limited and management mostly follows general recommendations, this review also aims to summarize data from the immunocompetent population.

RECENT FINDINGS

Potential risk factors for the development and progression of bronchiectasis include reduced immunoglobulins and lower CD4 cells. In addition, Pseudomonas aeruginosa and an altered microbiome might contribute to local inflammation and disease progression. Findings on the contribution of neutrophils and eosinophils in the affected immunocompetent population require confirmation in PAD. Despite its high global burden, there is an extreme paucity of data on chronic obstructive pulmonary disease in PAD. Lower IgA and IgM are associated with asthma in PAD, but the heterogeneity of prevalence among PAD groups is poorly understood. Recent observations of non-IgE-mediated pathomechanisms in asthma may be of particular interest in PAD patients.

SUMMARY

Management of PAD patients with chronic lung disease requires a multidisciplinary team approach including immunology, pulmonology, infectious disease and physiotherapy. Diagnostic processes should be harmonized to ensure a more precise perspective on prevalence and disease courses.

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.

Isolated IgG2 deficiency is an independent risk factor for exacerbations in bronchiectasis

BACKGROUND

Immunoglobulin G (IgG) subclass 2 deficiency is the most frequent IgG subclass deficiency identified in patients with bronchiectasis, but its clinical significance is not known.

AIM

To analyse if bronchiectasis patients with isolated IgG2 deficiency at risk of recurrent exacerbations and/or hospitalization? Do patients with IgG2 deficiency have worse disease progression?

DESIGN AND METHODS

This is a retrospective study (2015-20) exploring independent risk factors for recurrent exacerbations (3 or more per year) and/or hospitalization with bronchiectasis exacerbations using multivariable models using binary logistic regression. There was no patient with IgG deficiency, IgG 1, 3 or 4 deficiency, or IgA or IgM deficiency included. In this model, the authors included: serum IgG2 level; lung function; body mass index; MRC breathlessness scale; age; sex; number of bronchiectatic lobes; bacterial colonization; comorbidities; and the use of long-term immunosuppressant drugs or antibiotics for more than 28 days. Analysing 2-year longitudinal data, one-way ANOVA and Mann-Whitney U-test were used to compare bronchiectasis severity between patients with different IgG2 levels.

RESULTS

Serum IgG2 levels (<2.68 g/l, 2.68-3.53 g/l and 3.54-4.45 g/l); hospital admission in the preceding 2 years; bacterial colonization with potentially pathogenic organisms and asthma were independent predictors for three or more bronchiectasis exacerbations. Those with low IgG2 levels (<2.68 g/l and 2.68-3.53 g/l), had worsening progression of their bronchiectasis, using the Bronchiectasis Severity Index, over 1 year compared with those who were IgG2 replete (>4.45 g/l) (P = 0.003, 0.013).

CONCLUSION

Reduced IgG2 levels were an independent predictor for bronchiectasis exacerbations and have increased disease progression.

Practical guidance for the diagnosis and management of secondary hypogammaglobulinemia: A Work Group Report of the AAAAI Primary Immunodeficiency and Altered Immune Response Committees

Secondary hypogammaglobulinemia (SHG) is characterized by reduced immunoglobulin levels due to acquired causes of decreased antibody production or increased antibody loss. Clarification regarding whether the hypogammaglobulinemia is secondary or primary is important because this has implications for evaluation and management. Prior receipt of immunosuppressive medications and/or presence of conditions associated with SHG development, including protein loss syndromes, are histories that raise suspicion for SHG. In patients with these histories, a thorough investigation of potential etiologies of SHG reviewed in this report is needed to devise an effective treatment plan focused on removal of iatrogenic causes (eg, discontinuation of an offending drug) or treatment of the underlying condition (eg, management of nephrotic syndrome). When iatrogenic causes cannot be removed or underlying conditions cannot be reversed, therapeutic options are not clearly delineated but include heightened monitoring for clinical infections, supportive antimicrobials, and in some cases, immunoglobulin replacement therapy. This report serves to summarize the existing literature regarding immunosuppressive medications and populations (autoimmune, neurologic, hematologic/oncologic, pulmonary, posttransplant, protein-losing) associated with SHG and highlights key areas for future investigation.

A Randomized Double-Blind Placebo-Control Feasibility Trial of Immunoglobulin Treatment for Prevention of Recurrent Acute Exacerbations of COPD

Background

Observational studies suggest that immunoglobulin treatment may reduce the frequency of acute exacerbations of COPD (AECOPD).

Objective

To inform the design of a future randomised control trial (RCT) of intravenous immunoglobulin (IVIG) treatment efficacy for AECOPD prevention.

Methods

A pilot RCT was conducted. We recruited patients with COPD hospitalized for AECOPD, or from ambulatory clinics with one severe, or two moderate AECOPD in the previous year regardless of their serum IgG level. Patients were allocated in a 1:1 ratio with balanced randomisation to monthly IVIG or normal saline for 1 year. The primary outcome was feasibility defined as pre-specified accrual, adherence, and follow-up rates. Secondary outcomes included safety, tolerance, AECOPD rates, time to first AECOPD, quality of life, and healthcare costs.

Results

Seventy patients were randomized (37 female; mean age 67.7; mean FEV1 35.1%). Recruitment averaged 4.5±0.9 patients per month (range 0–8), 34 (49%) adhered to at least 80% of planned treatments, and four (5.7%) were lost to follow-up. There were 35 serious adverse events including seven deaths and one thromboembolism. None was related to IVIG. There were 56 and 48 moderate and severe AECOPD in the IVIG vs control groups. In patients with at least 80% treatment adherence, median time to first moderate or severe AECOPD was 275 vs 114 days, favoring the IVIG group (HR 0.76, 95% CI 0.3–1.92).

Conclusion

The study met feasibility criteria for recruitment and retention, but adherence was low. A trend toward more robust treatment efficacy in adherent patients supports further study, but future trials must address treatment adherence.

Trial registration number

NCT0290038, registered 24 February 2016, https://clinicaltrials.gov/ct2/show/NCT02690038 and NCT03018652, registered January 12, 2017, https://clinicaltrials.gov/ct2/show/NCT03018652.

Antibody Deficiency, Chronic Lung Disease, and Comorbid Conditions: A Case-Based Approach

New emerging pulmonary phenotypes associated with antibody deficiency, such as neutrophilic asthma, frequent exacerbations of chronic obstructive pulmonary disease, and unexplained interstitial lung disease, particularly in younger adults, are discussed in this review through a case-based approach. Also discussed in similar fashion are antibody deficiency syndromes that lead to end-stage lung disease and the indications for lung transplantation in primary immunodeficiency disease. These challenging cases require timely and individualized strategies for genetic and immunologic diagnosis, decisions about therapeutic approaches, and long-term monitoring.

Differential expression of sputum and serum autoantibodies in patients with chronic obstructive pulmonary disease

Chronic obstructive pulmonary disease (COPD) is a complex and progressive respiratory disease. Autoimmune processes have been hypothesized to contribute to disease progression; however, the presence of autoantibodies in the serum has been variable. Given that COPD is a lung disease, we sought to investigate whether autoantibodies in sputum supernatant would better define pulmonary autoimmune processes. Matched sputum and serum samples were obtained from the Airways Disease Endotyping for Personalized Therapeutics (ADEPT) study and at the Guangzhou Institute of Respiratory Health (GIRH). Samples were collected from patients with varying severity of COPD, asymptomatic smokers, and healthy control subjects. IgG and IgM autoantibodies were detected in sputum and serum of all subjects in both cohorts using a broad-spectrum autoantigen array. No differences were observed in sputum autoantibodies between COPD and asymptomatic smokers in either cohort. In contrast, 16% of detectable sputum IgG autoantibodies were decreased in subjects with COPD compared to healthy controls in the ADEPT cohort. Compared to asymptomatic smokers, approximately 13% of detectable serum IgG and 40% of detectable serum IgM autoantibodies were differentially expressed in GIRH COPD subjects. Of the differentially expressed specificities, anti-nuclear autoantibodies were predominately decreased. A weak correlation between increased serum IgM anti-tissue autoantibodies and a measure of airspace enlargement was observed. The differential expression of specificities varied between the cohorts. In closing, using a comprehensive autoantibody array, we demonstrate that autoantibodies are present in subjects with COPD, asymptomatic smokers, and healthy controls. Cohorts displayed high levels of heterogeneity, precluding the utilization of autoantibodies for diagnostic purposes.

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.

Efficacy and Safety of Different Doses of Systemic Corticosteroids in COPD Exacerbation

BACKGROUND

Although systemic corticosteroids (SCS) have long been used to treat patients with COPD exacerbation, the recommended dose remains controversial. We aimed to perform a meta-analysis and an indirect treatment comparison to investigate the efficacy and safety of different doses of SCS in subjects with COPD exacerbation.

METHODS

Studies were identified by searching different databases for randomized controlled trials that investigated the efficacy and safety of SCS with placebo in subjects with exacerbation of COPD. The different doses of SCS were assigned to low-dose (ie, initial dose ≤ 40 mg prednisone equivalent/d [PE/d]), medium-dose (initial dose = 40-100 mg PE/d, and high-dose (initial dose > 100 mg PE/d) groups. The indirect treatment comparison was performed between low-, medium-, and high-dose SCS groups.

RESULTS

Twelve trials with 1,375 participates were included. Compared to placebo, the risk of treatment failure was lower in the low-dose SCS groups (risk ratio 0.61 [95% CI 0.43-0.88], P = .007) and high-dose SCS groups (risk ratio 0.64 [95% CI 0.48-0.85], P = .002); the FEV₁ was significantly improved in low-dose (mean difference 0.09 [95% CI 0.06-0.12], P < .001), medium-dose (mean difference 0.23 [95% CI 0.02-0.44], P = .036), and high-dose SCS groups (mean difference 0.09, [95% CI 0.03-0.15], P < .001, respectively). Regarding safety, the incidence of hyperglycemia was higher in high-dose SCS groups versus placebo (risk ratio 2.52 [95% CI 1.13-5.62], P = .02). The indirect comparison between low-, medium-, and high-dose SCS found that the risk of treatment failure and changes in FEV₁ were similar between these doses of SCS.

CONCLUSIONS

This meta-analysis indicates that low-dose SCS (initial dose ≤ 40 mg PE/d) was sufficient and safer for treating subjects with COPD exacerbation, and it was noninferior to higher doses of SCS (initial dose > 40 mg PE/d) in improving FEV₁ and reducing the risk of treatment failure. However, our findings need to be verified in head-to-head randomized controlled trials.

Serum IgG Levels and Risk of COPD Hospitalization: A Pooled Meta-analysis

BACKGROUND

Hypogammaglobulinemia (serum IgG levels < 7.0 g/L) has been associated with increased risk of COPD exacerbations but has not yet been shown to predict hospitalizations.

RESEARCH QUESTION

To determine the relationship between hypogammaglobulinemia and the risk of hospitalization in patients with COPD.

STUDY DESIGN AND METHODS

Serum IgG levels were measured on baseline samples from four COPD cohorts (n = 2,259): Azithromycin for Prevention of AECOPD (MACRO, n = 976); Simvastatin in the Prevention of AECOPD (STATCOPE, n = 653), Long-Term Oxygen Treatment Trial (LOTT, n = 354), and COPD Activity: Serotonin Transporter, Cytokines and Depression (CASCADE, n = 276). IgG levels were determined by immunonephelometry (MACRO; STATCOPE) or mass spectrometry (LOTT; CASCADE). The effect of hypogammaglobulinemia on COPD hospitalization risk was evaluated using cumulative incidence functions for this outcome and deaths (competing risk). Fine-Gray models were performed to obtain adjusted subdistribution hazard ratios (SHR) related to IgG levels for each study and then combined using a meta-analysis. Rates of COPD hospitalizations per person-year were compared according to IgG status.

RESULTS

The overall frequency of hypogammaglobulinemia was 28.4%. Higher incidence estimates of COPD hospitalizations were observed among participants with low IgG levels compared with those with normal levels (Gray's test, P < .001); pooled SHR (meta-analysis) was 1.29 (95% CI, 1.06-1.56, P = .01). Among patients with prior COPD admissions (n = 757), the pooled SHR increased to 1.58 (95% CI, 1.20-2.07, P < .01). The risk of COPD admissions, however, was similar between IgG groups in patients with no prior hospitalizations: pooled SHR = 1.15 (95% CI, 0.86-1.52, P =.34). The hypogammaglobulinemia group also showed significantly higher rates of COPD hospitalizations per person-year: 0.48 ± 2.01 vs 0.29 ± 0.83, P < .001.

INTERPRETATION

Hypogammaglobulinemia is associated with a higher risk of COPD hospital admissions.

Hypogammaglobulinemia and Risk of Exacerbation and Mortality in Patients with COPD

Introduction

Chronic obstructive pulmonary disease (COPD) may, in some patients, be characterized by recurring acute exacerbations. Often these exacerbations are associated with airway infections. As immunoglobulins (Ig) are important parts of the immune defence against airway infections, the aim of this study was to relate the levels of circulating immunoglobulins to clinical features in unselected patients with COPD included in a Norwegian multicenter study.

Methods

Clinical and biological data, including circulating levels of immunoglobulins, were assessed in 262 prospectively included patients with COPD GOLD stage II-IV at five hospitals in south-eastern Norway. A revisit was done after one year, and survival was assessed after five years. Clinical features and survival of those with immunoglobulin levels below reference values were compared to those with normal levels.

Results

In total, 11.5% of all COPD patients and 18.5% of those with GOLD stage IV had IgG concentrations below reference values. These patients were more likely to use inhaled or oral steroids, had lower BMI, and lower FEV1%. Moreover, they had significantly more COPD-related hospital admissions (2.8 vs 0.6), number of prednisolone courses (3.9 vs 1.2), and antibiotic treatments (3.7 vs 1.5) in the preceding year. Importantly, hypogammaglobulinemia was significantly associated with reduced survival in a log-rank analysis. In multivariate regression analysis, we found that the higher risk for acute exacerbations in these patients was independent of other risk factors and was associated with impaired survival.

Conclusion

In conclusion, our study suggests that hypogammaglobulinemia may be involved in poor outcome in COPD and may thus be a feasible therapeutic target for interventional studies in COPD.

Risk factors of chronic obstructive pulmonary disease exacerbations

Chronic Obstructive Pulmonary Disease (COPD) is a chronic respiratory disease characterised by persistent respiratory symptoms and airflow limitation. COPD has a major impact on public health, mainly because of its increasing prevalence, morbidity and mortality. The natural course of COPD is aggravated by episodes of respiratory symptom worsening termed exacerbations that contribute to disease progression. Acute Exacerbations of COPD (AECOPD) can be triggered by a multitude of different factors, including respiratory tract infections, various exposures, prior exacerbations, non-adherence to treatment and associated comorbidities. AECOPD are associated with an inexorable decline of lung function and a significantly worse survival outcome. This review will summarise the most important aspects regarding the impact of different factors that contribute to COPD exacerbations.

Cigarette smoking differentially affects immunoglobulin class levels in serum and saliva: An investigation and review

The aim of the present study was to compare concentrations of IgG, IgA, IgM and IgD in both serum and saliva samples from smoking and non-smoking individuals using a protein microarray assay. The findings were also compared to previous studies. Serum and saliva were collected from 48 smoking male individuals and 48 age-matched never-smoker male individuals. The protein microarray assays for detection of human IgG, IgM, IgA and IgD were established and optimized using Ig class-specific affinity-purified goat anti-human Ig-Fc capture antibodies and horseradish peroxidase (HRP)-conjugated goat anti-human Ig-Fc detection antibodies. The Ig class specificity of the microarray assays was verified, and the optimal dilutions of serum and saliva samples were determined for quantification of Ig levels against standard curves. We found that smoking is associated with reduced IgG concentrations and enhanced IgA concentrations in both serum and saliva. By contrast, smoking differentially affected IgM concentrations-causing increased concentrations in serum, but decreased concentrations in saliva. Smoking was associated with decreased IgD concentrations in serum and did not have a significant effect on the very low IgD concentrations in saliva. Thus, cigarette smoking differentially affects the levels of Ig classes systemically and in the oral mucosa. Although there is variation between the results of different published studies, there is a consensus that smokers have significantly reduced levels of IgG in both serum and saliva. A functional antibody deficiency associated with smoking may compromise the body's response to infection and result in a predisposition to the development of autoimmunity.

Appropriate lung management in patients with primary antibody deficiencies

Introduction: Human primary immunodeficiency diseases (PIDs) include a broad spectrum of more than 350 disorders, involving different branches of the immune system and classified as 'rare diseases.' Predominantly antibody deficiencies (PADs) represent more than half of the PIDs diagnosed in Europe and are often diagnosed in the adulthood. Areas covered: Although PAD could first present with autoimmune or neoplastic features, respiratory infections are frequent and respiratory disease represents a relevant cause of morbidity and mortality. Pulmonary complications may be classified as infection-related (acute and chronic), immune-mediated, and neoplastic. Expert opinion: At present, no consensus guidelines are available on how to monitor and manage lung complications in PAD patients. In this review, we will discuss the available diagnostic, prognostic and therapeutic instruments and we will suggest an appropriate and evidence-based approach to lung diseases in primary antibody deficiencies. We will also highlight the possible role of promising new tools and strategies in the management of pulmonary complications. However, future studies are needed to reduce of diagnostic delay of PAD and to better understand lung diseases mechanisms, with the final aim to ameliorate therapeutic options that will have a strong impact on Quality of Life and long-term prognosis of PAD patients.

Precision health: treating the individual patient with chronic obstructive pulmonary disease

Chronic obstructive pulmonary disease (COPD) is defined based on a reduced ratio of forced expiratory volume in one second (FEV₁ ) to forced vital capacity (FVC) on spirometry. However, within this definition, there is significant heterogeneity of pathophysiological processes that lead to airflow obstruction and variation in phenotypic manifestations across patients. Current pharmacological treatments are based on large randomised clinical trials that apply to an "average" patient. Precision health enables tailoring of treatment for each individual patient by taking into account their unique characteristics. The number needed to treat (NNT) metric is often used to define implementation of precision health for specific interventions, with common endpoints requiring an NNT ≤ 5 to achieve precision therapy. Higher NNTs may be acceptable for rare but important endpoints such as mortality. Long-acting muscarinic antagonists and inhaled corticosteroids, which are commonly used in COPD, have 1-year treatment NNTs between 15 and 20 for exacerbation prevention in unselected patients with COPD. Subgroup identification using biomarkers or clinical traits may enable precision health. For example, NNT for inhaled corticosteroids is 9 in patients with a blood eosinophil count ≥ 300 cells/μL and 8 for long-acting muscarinic antagonists in patients with a body mass index ≤ 20 kg/m² . Lung volume reduction surgery is associated with an NNT of 6 for survival over 5 years in patients with upper lobe-predominant disease and low exercise capacity (whereas the NNT is 245 when no bioimaging or exercise markers are used). Continuous domiciliary oxygen therapy (for at least 15 hours/day) has an NNT of 5 for survival over 5 years in patients with resting hypoxemia (PaO₂  < 60 mmHg on room air). Emerging areas of precision health in COPD with potential for low NNTs in specific circumstances include anti-interleukin-5 therapy for eosinophilic COPD, and immunoglobulin replacement therapy for patients with severe immunoglobulin deficiency.

Introduction to precision medicine in COPD

Although there has been tremendous growth in our understanding of chronic obstructive pulmonary disease (COPD) and its pathophysiology over the past few decades, the pace of therapeutic innovation has been extremely slow. COPD is now widely accepted as a heterogeneous condition with multiple phenotypes and endotypes. Thus, there is a pressing need for COPD care to move from the current “one-size-fits-all” approach to a precision medicine approach that takes into account individual patient variability in genes, environment and lifestyle. Precision medicine is enabled by biomarkers that can: 1) accurately identify subgroups of patients who are most likely to benefit from therapeutics and those who will only experience harm (predictive biomarkers); 2) predict therapeutic responses to drugs at an individual level (response biomarkers); and 3) segregate patients who are at risk of poor outcomes from those who have relatively stable disease (prognostic biomarkers). In this essay, we will discuss the current concept of precision medicine and its relevance for COPD and explore ways to implement precision medicine for millions of patients across the world with COPD.

The broad spectrum of lung diseases in primary antibody deficiencies

Human primary immunodeficiency diseases (PIDs) represent a heterogeneous group of more than 350 disorders. They are rare diseases, but their global incidence is more relevant than generally thought. The underlying defect may involve different branches of the innate and/or adaptive immune response. Thus, the clinical picture may range from severe phenotypes characterised by a broad spectrum of infections to milder infectious phenotypes due to more selective (and frequent) immune defects. Moreover, infections may not be the main clinical features in some PIDs that might present with autoimmunity, auto-inflammation and/or cancer. Primary antibody deficiencies (PADs) represent a small percentage of the known PIDs but they are the most frequently diagnosed, particularly in adulthood. Common variable immunodeficiency (CVID) is the most prevalent symptomatic PAD.

PAD patients share a significant susceptibility to respiratory diseases that represent a relevant cause of morbidity and mortality. Pulmonary complications include acute and chronic infection-related diseases, such as pneumonia and bronchiectasis. They also include immune-mediated interstitial lung diseases, such as granulomatous-lymphocytic interstitial lung disease (GLILD) and cancer. Herein we will discuss the main pulmonary manifestations of PADs, the associated functional and imaging findings, and the relevant role of pulmonologists and chest radiologists in diagnosis and surveillance.

The spectrum of lung complications in primary antibody deficiency ranges from asthma or COPD to extremely rare and specific ILDs. Early diagnosis of the underlying immune defect might significantly improve patients' lung disease, QoL and long-term prognosis.http://ow.ly/5cP230kZvOB

Study protocol: a randomized, double-blind, parallel, two-arm, placebo control trial investigating the feasibility and safety of immunoglobulin treatment in COPD patients for prevention of frequent recurrent exacerbations

Background

Chronic obstructive pulmonary disease (COPD) is a chronic progressive inflammatory disease of the airways, associated with frailty, disability, co-morbidity, and mortality. Individuals with COPD experience increased risk and rates of acute exacerbation as their lung disease worsens. Current treatments to prevent acute exacerbation of COPD (AECOPD) are only modestly effective. New therapies are needed to improve the quality of life and clinical outcomes for individuals living with COPD and especially for those prone to frequent recurrent AECOPD. Recent research has suggested an association of gammaglobulin or immunoglobulin G levels with AECOPD and a favorable effect of an immunoglobulin treatment on the frequency of recurrent AECOPD, healthcare provider visits, treatments, and hospitalizations. However, control trials are required to confirm this apparent association and therapeutic effect. This study aims to assess if intravenous immunoglobulin (IVIG) therapy is feasible, safe, tolerable, and potentially effective in reducing the frequency of recurrent AECOPD.

Methods/design

Adult COPD patients at The Ottawa Hospital (TOH) will be recruited to partake in a randomized double-blind, parallel, two-arm, placebo control trial. Eligible patients will be administered either IVIG or normal saline following 1:1 randomization and every 4 weeks for 1 year. The primary outcome of feasibility will be determined by recruitment, patient adherence, safety and tolerance, success of the follow-up procedures, and outcome measurement. The safety and tolerability will be assessed through adverse events, adherence, and study withdrawals. Efficacy trends will be investigated by assessing incidence rates of AECOPD, improvement in quality of life, and healthcare services use and cost.

Discussion

The study results will inform larger studies designed to confirm a clinically significant therapeutic effect in identifiable populations which would be a major advance in the care of COPD patients.

Trial registration number

ClinicalTrial.gov, NCT03018652 and NCT02690038.

Lower serum IgA is associated with COPD exacerbation risk in SPIROMICS

Background

Decreased but measurable serum IgA levels (≤70 mg/dL) have been associated with risk for infections in some populations, but are unstudied in COPD. This study tested the hypothesis that subnormal serum IgA levels would be associated with exacerbation risk in COPD.

Methods

Data were analyzed from 1,049 COPD participants from the observational cohort study SPIROMICS (535 (51%) women; mean age 66.1 (SD 7.8), 338 (32%) current smokers) who had baseline serum IgA measured using the Myriad RBM biomarker discovery platform. Exacerbation data was collected prospectively (mean 944.3 (SD 281.3) days), and adjusted linear, logistic and zero-inflated negative binomial regressions were performed.

Results

Mean IgA was 269.1 mg/dL (SD 150.9). One individual had deficient levels of serum IgA (<7 mg/dL) and 25 (2.4%) had IgA level ≤70 mg/dL. Participants with IgA ≤70 mg/dL were younger (62 vs. 66 years, p = 0.01) but otherwise similar to those with higher IgA. In adjusted models, IgA ≤70 mg/dL was associated with higher exacerbation incidence rates (IRR 1.71, 95% CI 1.01–2.87, p = 0.044) and greater risk for any severe exacerbation (OR 2.99, 95% CI 1.30–6.94, p = 0.010). In adjusted models among those in the lowest decile (<120 mg/dL), each 10 mg/dL decrement in IgA (analyzed continuously) was associated with more exacerbations during follow-up (β 0.24, 95% CI 0.017–0.46, p = 0.035).

Conclusions

Subnormal serum IgA levels were associated with increased risk for acute exacerbations, supporting mildly impaired IgA levels as a contributing factor in COPD morbidity. Additionally, a dose-response relationship between lower serum IgA and number of exacerbations was found among individuals with serum IgA in the lowest decile, further supporting the link between serum IgA and exacerbation risk. Future COPD studies should more comprehensively characterize immune status to define the clinical relevance of these findings and their potential for therapeutic correction.

Serum IgG subclass levels and risk of exacerbations and hospitalizations in patients with COPD

BACKGROUND

The literature is scarce regarding the prevalence and clinical impact of IgG subclass deficiency in COPD. We investigated the prevalence of IgG subclass deficiencies and their association with exacerbations and hospitalizations using subjects from two COPD cohorts.

METHODS

We measured IgG subclass levels using immunonephelometry in serum samples from participants enrolled in two previous COPD trials: Macrolide Azithromycin for Prevention of Exacerbations of COPD (MACRO; n = 976) and Simvastatin for the Prevention of Exacerbations in Moderate-to-Severe COPD (STATCOPE; n = 653). All samples were collected from clinically stable participants upon entry into both studies. IgG subclass deficiency was diagnosed when IgG subclass levels were below their respective lower limit of normal: IgG1 < 2.8 g/L; IgG2 < 1.15 g/L; IgG3 < 0.24 g/L; and IgG4 < 0.052 g/L. To investigate the impact of IgG subclass levels on time to first exacerbation or hospitalization, we log-transformed IgG levels and performed Cox regression models, with adjustments for confounders.

RESULTS

One or more IgG subclass deficiencies were found in 173 (17.7%) and 133 (20.4%) participants in MACRO and STATCOPE, respectively. Lower IgG1 or IgG2 levels resulted in increased risk of exacerbations with adjusted hazard ratios (HR) of 1.30 (95% CI, 1.10-1.54, p < 0.01) and 1.19 (95% CI, 1.05-1.35, p < 0.01), respectively in the MACRO study, with STATCOPE yielding similar results. Reduced IgG1 or IgG2 levels were also associated with increased risk of hospitalizations: the adjusted HR for IgG1 and IgG2 was 1.52 (95% CI: 1.15-2.02, p < 0.01) and 1.33 (95% CI, 1.08-1.64, p < 0.01), respectively for the MACRO study; in STATCOPE, only IgG2 was an independent predictor of hospitalization. In our multivariate Cox models, IgG3 and IgG4 levels did not result in significant associations for both outcomes in either MACRO or STATCOPE cohorts.

CONCLUSIONS

Approximately 1 in 5 COPD patients had one or more IgG subclass deficiencies. Reduced IgG subclass levels were independent risk factors for both COPD exacerbations (IgG1 and IgG2) and hospitalizations (IgG2) in two COPD cohorts.

TRIAL REGISTRATION

This study used serum samples from participants of the MACRO ( NCT00325897 ) and STATCOPE ( NCT01061671 ) trials.

Primary immune deficiency diseases as unrecognized causes of chronic respiratory disease

BACKGROUND

More than half of all primary immune deficiency diseases (PIDD) affect antibody production and are well known as causes of recurrent sinusitis and lung infections. Chronic and recurrent infections of the upper and/or lower airways can contribute to inflammatory and obstructive processes in the lower airways which are initially reversible and considered "asthma", but can eventually cause irreversible remodeling and chronic obstructive pulmonary disease (COPD). Conversely, several lines of evidence suggest that many patients who present with a diagnosis of asthma have an increased incidence of infection, suggesting underlying host-defense defects. Asthma and respiratory infections in the first decades of life are recognized as risk factors for development of COPD, but when patients present with COPD as adults, underlying primary immune deficiency disease may be unrecognized.

MAIN FINDINGS AND CONCLUSIONS

Detection of PIDD as a potentially treatable underlying contributor to recurrent/acute exacerbations and morbidity of COPD, and provision of immunoglobulin (Ig) G replacement therapy, when appropriate, may decrease the progression of COPD. Decreasing the severity and rate of exacerbations and admissions should improve the quality of life and longevity of an important subset of patients with COPD, while decreasing costs. Major steps toward achieving these goals include developing a high index of suspicion, more frequent use and appropriate interpretation of screening tests such as quantitative immunoglobulins and vaccine responses, and prompt institution of IgG replacement therapy when antibody deficiency has been diagnosed.

Antibody deficiency in patients with frequent exacerbations of Chronic Obstructive Pulmonary Disease (COPD)

Chronic Obstructive Pulmonary Disease is the third leading cause of death in the US, and is associated with periodic exacerbations, which account for the largest proportion of health care utilization, and lead to significant morbidity, mortality, and worsening lung function. A subset of patients with COPD have frequent exacerbations, occurring 2 or more times per year. Despite many interventions to reduce COPD exacerbations, there is a significant lack of knowledge in regards to their mechanisms and predisposing factors. We describe here an important observation that defines antibody deficiency as a potential risk factor for frequent COPD exacerbations. We report a case series of patients who have frequent COPD exacerbations, and who were found to have an underlying primary antibody deficiency syndrome. We also report on the outcome of COPD exacerbations following treatment in a subset with of these patients with antibody deficiency. We identified patients with COPD who had 2 or more moderate to severe exacerbations per year; immune evaluation including serum immunoglobulin levels and pneumococcal IgG titers was performed. Patients diagnosed with an antibody deficiency syndrome were treated with either immunoglobulin replacement therapy or prophylactic antibiotics, and their COPD exacerbations were monitored over time. A total of 42 patients were identified who had 2 or more moderate to severe COPD exacerbations per year. Twenty-nine patients had an underlying antibody deficiency syndrome: common variable immunodeficiency (8), specific antibody deficiency (20), and selective IgA deficiency (1). Twenty-two patients had a follow-up for at least 1 year after treatment of their antibody deficiency, which resulted in a significant reduction of COPD exacerbations, courses of oral corticosteroid use and cumulative annual dose of oral corticosteroid use, rescue antibiotic use, and hospitalizations for COPD exacerbations. This case series identifies antibody deficiency as a potentially treatable risk factor for frequent COPD exacerbations; testing for antibody deficiency should be considered in difficult to manage frequently exacerbating COPD patients. Further prospective studies are warranted to further test this hypothesis.

Relationships between Mucosal Antibodies, Non-Typeable Haemophilus influenzae (NTHi) Infection and Airway Inflammation in COPD

Non-typeable Haemophilus influenzae (NTHi) is a key pathogen in COPD, being associated with airway inflammation and risk of exacerbation. Why some patients are susceptible to colonisation is not understood. We hypothesised that this susceptibility may be due to a deficiency in mucosal humoral immunity. The aim of our study (NCT01701869) was to quantify the amount and specificity of antibodies against NTHi in the lungs and the associated risk of infection and inflammation in health and COPD. Phlebotomy, sputum induction and bronchoscopy were performed on 24 mild-to-moderate COPD patients and 8 age and smoking-matched controls. BAL (Bronchoalveolar lavage) total IgG1, IgG2, IgG3, IgM and IgA concentrations were significantly increased in COPD patients compared to controls. NTHi was detected in the lungs of 7 of the COPD patients (NTHi+ve-29%) and these patients had a higher median number of previous exacerbations than NTHi-ve patients as well as evidence of increased systemic inflammation. When comparing NTHi+ve versus NTHi-ve patients we observed a decrease in the amount of both total IgG1 (p = 0.0068) and NTHi-specific IgG1 (p = 0.0433) in the BAL of NTHi+ve patients, but no differences in total IgA or IgM. We observed no evidence of decreased IgG1 in the serum of NTHi+ve patients, suggesting this phenomenon is restricted to the airway. Furthermore, the NTHi+ve patients had significantly greater levels of IL-1β (p = 0.0003), in BAL than NTHi-ve COPD patients.This study indicates that the presence of NTHi is associated with reduced levels and function of IgG1 in the airway of NTHi-colonised COPD patients. This decrease in total and NTHI-specific IgG1 was associated with greater systemic and airway inflammation and a history of more frequent exacerbations and may explain the susceptibility of some COPD patients to the impacts of NTHi.

Subcutaneous Immunoglobulin Therapy in the Chronic Management of Myasthenia Gravis: A Retrospective Cohort Study

BACKGROUND

Immunoglobulin therapy has become a major treatment option in several autoimmune neuromuscular disorders. For patients with Myasthenia Gravis (MG), intravenous immunoglobulin (IVIg) has been used for both crisis and chronic management. Subcutaneous Immunoglobulins (SCIg), which offer the advantage of home administration, may be a practical and effective option in chronic management of MG. We analyzed clinical outcomes and patient satisfaction in nine cases of chronic disabling MG who were either transitioned to, or started de novo on SCIg.

METHODS AND FINDINGS

This was a retrospective cohort study for the period of 2015-2016, with a mean follow-up period of 6.8 months after initiation of SCIg. All patients with MG treated with SCIg at the Ottawa Hospital, a large Canadian tertiary hospital with subspecialty expertise in neuromuscular disorders were included, regardless of MG severity, clinical subtype and antibody status. The primary outcome was MG disease activity after SCIg initiation. This outcome was measured by 1) the Myasthenia Gravis Foundation of America (MGFA) clinical classification, and 2) subjective scales of disease activity including the Myasthenia Gravis activities of daily living profile (MG-ADL), Myasthenia Gravis Quality-of-life (MG-QOL 15), Visual Analog (VA) satisfaction scale. We also assessed any requirement for emergency department visits or hospitalizations. Safety outcomes included any SCIg related complication. All patients were stable or improved for MGFA class after SCIg initiation. Statistically significant improvements were documented in the MG-ADL, MG-QOL and VAS scales. There were no exacerbations after switching therapy and no severe SCIg related complications.

CONCLUSIONS

SCIg may be a beneficial therapy in the chronic management of MG, with favorable clinical outcome and patient satisfaction results.