RA autoantibodies as predictors of rheumatoid arthritis in non-cystic fibrosis bronchiectasis patients

Causal relationship between rheumatoid arthritis and bronchiectasis: a bidirectional mendelian randomization study

BACKGROUND

Epidemiological observational studies have elucidated a correlation between rheumatoid arthritis (RA) and bronchiectasis. However, the causal nature of this association remains ambiguous. To clarify this potential causal linkage, we conducted a two-sample Mendelian randomization (MR) analysis to explore the bidirectional causality between RA and bronchiectasis.

METHODS

Summary statistics for RA and bronchiectasis were obtained from the IEU OpenGWAS database We employed various methods, including inverse variance weighting (IVW), MR-Egger, weighted median, weighted mode, and simple mode, to explore potential causal links between RA and bronchiectasis. Additionally, a series of sensitivity studies, such as Cochran's Q test, MR Egger intercept test, and leave-one-out analysis, were conducted to assess the MR analysis's accuracy further.

RESULTS

In the forward MR analysis, the primary analysis indicated that a genetic predisposition to RA correlated with an increased risk of bronchiectasis in European populations (IVW odds ratio (OR): 1.28, 95% confidence interval (CI): 1.20-1.37, p = 1.18E-13). Comparable results were noted in the East Asian subjects (IVW OR: 1.55, 95% CI: 1.30-1.34, p = 8.33E-07). The OR estimates from the other four methods were consistent with those obtained from the IVW method. Sensitivity analysis detected no evidence of horizontal pleiotropy or heterogeneity. Conversely, in the reverse MR analysis, we found no evidence to support a genetic causality between bronchiectasis and RA in either European or East Asian populations.

CONCLUSION

This study indicates that genetic predisposition to RA correlates with a heightened risk of bronchiectasis in both European and East Asian populations. These results imply that routine screening for bronchiectasis in RA patients could be beneficial, and effective management of RA may contribute to a reduced risk of bronchiectasis. Future research should aim to clarify the underlying mechanisms linking these two conditions.

Clinical characteristics of rheumatoid arthritis patients complicated with pulmonary nontuberculous mycobacterial disease: A cross-sectional case series study

OBJECTIVES

Pulmonary nontuberculous mycobacterial disease (pNTM) is a common pulmonary complication of rheumatoid arthritis (RA), but their association has rarely been researched. We aimed to reveal the clinical characteristics of RA with pNTM.

METHODS

Among all the RA patients who visited Tenri hospital from April 2017 to March 2018, we enrolled those fulfilling the 2007 ATS/IDSA diagnostic criteria of pNTM, and sex- and age- matched control group at a ratio of 1:5. Demographic characteristics were compared between the two groups.

RESULTS

Among 865 RA patients, 35 (4.0%) patients were complicated with pNTM. RA patients with pNTM had significantly lower BMI and higher rheumatoid factor (RF) and anti-citrullinated protein antibody (ACPA) positivity. Bronchiectasis was the most frequent lesion, followed by clusters of small nodules, patchy consolidation and cavity. Multivariable logistic regression analysis revealed bronchiectasis as a strong independent associated factor of pNTM. Treatment for pNTM was needed in 14 of the 35 (40%) RA patients with pNTM and sputum negative conversion was accomplished in 11 of the 14 cases (78.6%).

CONCLUSIONS

RA patients with lower BMI, RF/ACPA positivity, and bronchiectasis were associated with pNTM. Treatment for pNTM may attain sputum negative conversion and radiological improvement in patients with RA.

Clinical outcomes and prognostic factors of bronchiectasis rheumatoid overlap syndrome: A multi-institution cohort study

The information regarding bronchiectasis with RA (BROS) is limited in Asia. The objective of this study was to investigate the clinical characteristics and outcomes of BROS in Taiwan. This multi-institute cohort study included patients with BROS from January 2006 to December 2017. The clinical, functional and microbiological data of these patients were retrieved from the Chang Gung Research Database. Respiratory failure and mortality were the primary outcomes. Severe exacerbation was defined as bronchiectasis- related hospitalizations or emergency department visits. A total of 343 patients with BROS were identified. One hundred and eight patients had severe exacerbation and exhibited significantly more previous exacerbations, a lower FEV1 and higher BACI score (11.1 vs. 7.5) than patients without severe exacerbation. The most prevalent species in sputum were Non-tuberculous mycobacteria (NTM) (14.8 %), Pseudomonas aeruginosa (14.2 %), and fungus (5.9%). 68.8% of BROS patients used disease modifying antirheumatic drugs (DMARD), 7.9% used biological DMARD. NTM and tuberculosis infection rates were higher in bDMARD group compared with nbDMARD group and others. Overall, the 3-year respiratory failure rate and mortality rate were 14.6 and 25.7% respectively. Patients with RA diagnosed before bronchiectasis had a significantly higher cumulative incidence of mortality in a 3-year follow-up than those with RA diagnosed after bronchiectasis. In Cox regression, age, higher RF value and systemic steroid use were independent risk factors for mortality in BROS. BROS patients with severe exacerbation had a high mortality rate in Taiwan. bDMARD is associated with a trend of increased risk of NTM and TB infections.

Development of Rheumatoid Arthritis in Cavitary Mycobacterium avium Pulmonary Disease: A Case Report of Successful Treatment with CTLA4-Ig (Abatacept)

Background

Nontuberculous mycobacterial pulmonary disease (NTM-PD) often develops in patients with rheumatoid arthritis (RA), especially during immunosuppressive treatment, including biological disease-modifying antirheumatic drugs. NTM-PD is associated with airway lesions such as bronchiectasis, which is frequently seen in RA patients. Distinguishing which diseases cause the pulmonary lesion is difficult. However, there are limited reports of the development of RA during the follow-up of NTM-PD and how biological agents should be administered in these conditions, especially with cavitary lesions.

Case Presentation

A 62-year-old woman with hemosputum was referred to our hospital, where she was diagnosed with Mycobacterium avium pulmonary disease. She began treatment with several antibiotics, including clarithromycin, ethambutol, rifampicin, and amikacin. In the course of treatment, M. avium became macrolide-resistant. Five years after beginning antibiotic treatment, she felt arthralgia in the fingers and wrists and had a high titer of rheumatoid factor and anticitrullinated peptide antibody, with which we diagnosed RA. Methotrexate, prednisolone, and iguratimod were subsequently administered, but the activity of RA gradually worsened. Meanwhile, M. avium changed to a macrolide-susceptible strain, her sputum smear results remained almost negative, and the NTM-PD disease was well controlled with antimicrobial therapy, despite her having cavitary lesions. Therefore, we started using CTLA4-Ig (abatacept). RA symptoms were substantially ameliorated. The pulmonary lesions and NTM-PD worsened mildly, but her pulmonary symptoms were stable.

Conclusion

Physicians should be mindful of the etiologies of bronchiectasis, including RA, even in patients with a long-term history of treatment for bronchiectasis and NTM-PD. When NTM-PD is well controlled, even with remaining cavitary lesions, abatacept may be an option for patients with RA based on a comprehensive assessment of disease progression using NTM sputum smear/culture, computed tomography findings, and treatment response.

Comorbidities and mortality risk factors for patients with bronchiectasis

Introduction: Comorbidities in patients with bronchiectasis are common and have a significant impact on clinical outcomes, contributing to lower quality of life, lung function, and exacerbation frequency. At least 13 comorbidities have been associated with a higher risk of mortality in bronchiectasis patients. Nonetheless, the kind of relationship between bronchiectasis and comorbidities is heterogeneous and poorly understood.Areas covered: different biological mechanisms leading to bronchiectasis could have a role in the development of the associated comorbidities. Some comorbidities could have a causal relationship with bronchiectasis, possibly through a variable degree of systemic inflammation, such as in rheumatic disorders and bowel inflammatory diseases. Other comorbidities, such as COPD or asthma, could be associated through airway inflammation and there is an uncertain cause-effect relationship. Finally, shared risk factors could link different comorbidities to bronchiectasis such as in the case of cardiovascular diseases, where the known link between chronic systemic inflammation and pulmonary infection could play a significant role.Expert opinion: Although different tools have been developed to assess the role of comorbidities in bronchiectasis , we believe that the implementation of current strategies to manage them is absolutely necessary and could significantly improve long-term prognosis in patients with bronchiectasis.

Non-CF bronchiectasis: Orphan disease no longer

Bronchiectasis is a complex, chronic respiratory condition, characterized by frequent cough and exertional dyspnea due to a range of conditions that include inherited mucociliary defects, inhalational airway injury, immunodeficiency states and prior respiratory infections. For years, bronchiectasis was classified as either being caused by cystic fibrosis or non-cystic fibrosis. Non-cystic fibrosis bronchiectasis, once considered an orphan disease, is more prevalent worldwide in part due to greater availability of chest computed tomographic imaging. Identification of the cause of non-cystic fibrosis bronchiectasis with the use of chest imaging, laboratory testing, and microbiologic assessment of airway secretions can lead to initiation of specific therapies aimed at slowing disease progression. Nonpharmacologic therapies such as airway clearance techniques and pulmonary rehabilitation improve patient symptoms. Inhaled corticosteroids should not be routinely prescribed unless concomitant asthma or COPD is present. Inhaled antibiotics prescribed to individuals with >3 exacerbations per year are well tolerated, reduce airway bacteria load and may reduce the frequency of exacerbations. Likewise, chronic macrolide therapy reduces the frequency of exacerbations. Medical therapies for cystic fibrosis bronchiectasis may not be effective in treatment of non-cystic fibrosis bronchiectasis.

Bronchiectasis in rheumatoid arthritis. A clinical appraisial

Bronchiectasis is defined as irreversibly damaged and dilated bronchi and is one of the most common pulmonary manifestations in patients with rheumatoid arthritis (RA). The model of RA-associated autoimmunity induced in some individuals by chronic bacterial infection in bronchiectasis is becoming increasingly acceptable, although a genetic predisposition to RA-associated bronchiectasis has also been demonstrated. Bronchiectasis should be suspected in RA patients with chronic cough and sputum production or frequent respiratory infections and the diagnosis must be confirmed by thoracic high-resolution computed tomography. Management of patients with RA-associated bronchiectasis includes a multimodal treatment approach. Similar to all patients with non-cystic fibrosis bronchiectasis, patients with RA-associated bronchiectasis benefit from a pulmonary rehabilitation program, including an exercise/muscle strengthening program and an education program with a specific session on airway clearance techniques. Prophylactic antibiotics are recommended for patients with frequent (3 or more infective exacerbations per year) or severe infections requiring hospitalization/intravenous antibiotics and inhaled corticosteroids and long-acting β2-agonists should be used in patients with non-cystic fibrosis bronchiectasis and associated airway hyper-responsiveness. In patients with RA-associated bronchiectasis the use of immunomodulatory drugs has to be carefully considered, as they are essential to control disease activity, despite being associated with an increased infectious risk. Pneumococcal and influenza vaccines are advised to all patients with RA-associated bronchiectasis in order to reduce the risk of infection. Patients with RA-associated bronchiectasis have a poorer prognosis than those with either RA or bronchiectasis alone and require regular follow-up, under the joint care of a rheumatologist and a pulmonologist.

Asthma and elevation of anti-citrullinated protein antibodies prior to the onset of rheumatoid arthritis

BACKGROUND

Anti-citrullinated protein antibodies (ACPA) are central to rheumatoid arthritis (RA) pathogenesis and may develop at inflamed mucosa. We investigated whether asthma, a disease of airway mucosal inflammation, was associated with elevated ACPA before RA diagnosis.

METHODS

We performed a nested case-control study among women in two prospective cohorts, the Nurses' Health Study (NHS; 1976-2014) and NHSII (1989-2015). Blood was obtained on a subset (NHS: 1989-1990; NHSII: 1996-1999). Cases met 1987 ACR or 2010 ACR/EULAR RA criteria by medical record review and were classified as seropositive (ACPA+ or rheumatoid factor positivity) or seronegative by clinical laboratory testing at diagnosis. We identified RA cases with blood drawn before the date of RA diagnosis (index date), matching each to three controls by age, cohort, year, time from blood draw to index date, and menopause. Pre-RA ACPA elevation for cases was defined as >99th percentile of the control distribution on a research assay composed of autoantibodies targeting citrullinated protein epitopes or positivity on the second-generation commercial assay for cyclic citrullinated peptide. Asthma status and covariates were obtained through biennial questionnaires before blood draw. Conditional logistic regression estimated ORs and 95%CIs for RA by pre-RA ACPA and clinical serostatus, adjusted for matching factors, smoking pack-years, passive smoking, and body mass index (BMI).

RESULTS

We identified 284 incident RA cases and 849 matched controls; mean age at the index date was 61.2 years (SD 10.1). Blood was drawn 9.7 years (mean; SD 5.8) before the index date. We identified 96 (33.8%) RA cases with elevated pre-RA ACPA. At blood draw, 17.7% of pre-RA ACPA+ cases and 6.3% of matched controls (p = 0.0008) reported clinician-diagnosed asthma. After adjusting for matching factors, smoking pack-years, passive smoking, and BMI, asthma was significantly associated with pre-RA ACPA+ RA (OR 3.57, 95%CI 1.58,8.04). Asthma was not associated with overall RA (OR 1.45, 95%CI 0.91,2.31), but was significantly associated with seropositive RA (OR 1.79, 95%CI 1.01,3.18).

CONCLUSIONS

Asthma was strongly associated with ACPA elevation in blood drawn prior to RA diagnosis, independent of smoking. Chronic mucosal airway inflammation may contribute to ACPA development and RA pathogenesis.

Galectin-9 Is a Possible Promoter of Immunopathology in Rheumatoid Arthritis by Activation of Peptidyl Arginine Deiminase 4 (PAD-4) in Granulocytes

The aetiology of rheumatoid arthritis (RA) is unknown, but citrullination of proteins is thought to be an initiating event. In addition, it is increasingly evident that the lung can be a potential site for the generation of autoimmune triggers before the development of joint disease. Here, we identified that serum levels of galectin-9 (Gal-9), a pleiotropic immunomodulatory protein, are elevated in RA patients, and are even further increased in patients with comorbid bronchiectasis, a lung disease caused by chronic inflammation. The serum concentrations of Gal-9 correlate with C-reactive protein levels and DAS-28 score. Gal-9 activated polymorphonuclear leukocytes (granulocytes) in vitro, which was characterized by increased cytokine secretion, migration, and survival. Further, granulocytes treated with Gal-9 upregulated expression of peptidyl arginine deiminase 4 (PAD-4), a key enzyme required for RA-associated citrullination of proteins. Correspondingly, treatment with Gal-9 triggered citrullination of intracellular granulocyte proteins that are known contributors to RA pathogenesis (i.e., myeloperoxidase, alpha-enolase, MMP-9, lactoferrin). In conclusion, this study identifies for the first time an immunomodulatory protein, Gal-9, that triggers activation of granulocytes leading to increased PAD-4 expression and generation of citrullinated autoantigens. This pathway may represent a potentially important mechanism for development of RA.

Marked deterioration in rheumatoid arthritis associated bronchiectasis following treatment with Rituximab

We report a 67 year old lady with Rheumatoid Arthritis (RA) and mild bronchiectasis (BE) whose treatment was escalated to Rituximab. Nine months after commencing Rituximab her lung sepsis worsened dramatically with repeated hospitalization, new sputum isolation of Stenotrophomonas maltophilia and Pseudomonas aeruginosa and marked radiological deterioration in BE. She was found to have a low serum IgG and IgM levels almost certainly as a complication of Rituximab. Immunoglobulin replacement therapy was instituted and her clinical status has slowly improved.

Economic burden of bronchiectasis in Germany

Estimates of healthcare costs for incident bronchiectasis patients are currently not available for any European country.

Out of a sample of 4 859 013 persons covered by German statutory health insurance companies, 231 new bronchiectasis patients were identified in 2012. They were matched with 685 control patients by age, sex and Charlson Comorbidity Index, and followed for 3 years.

The total direct expenditure during that period per insured bronchiectasis patient was EUR18 634.57 (95% CI EUR15 891.02–23 871.12), nearly one-third higher (ratio of mean 1.31, 95% CI 1.02–1.68) than for a matched control (p<0.001). Hospitalisation costs contributed to 35% of the total and were >50% higher in the bronchiectasis group (ratio of mean 1.56, 95% CI 1.20–3.01; p<0.001); on average, bronchiectasis patients spent 4.9 (95% CI 2.27–7.43) more days in hospital (p<0.001). Antibiotics expenditures per bronchiectasis outpatient (EUR413.81) were nearly 5 times higher than those for a matched control (ratio of mean 4.85, 95% CI 2.72–8.64). Each bronchiectasis patient had on average 40.5 (95% CI 17.1–43.5) sick-leave days and induced work-loss costs of EUR4230.49 (95% CI EUR2849.58–5611.20). The mortality rate for bronchiectasis and matched non-bronchiectasis patients after 3 years of follow-up was 26.4% and 10.5%, respectively (p<0.001). Mortality in the bronchiectasis group was higher among those who also had chronic obstructive lung disease than in patients with bronchiectasis alone (35.9% and 14.6%, respectively; p<0.001).

Although bronchiectasis is considered underdiagnosed, the mortality and associated financial burden in Germany are substantial.

Nintedanib reduces pulmonary fibrosis in a model of rheumatoid arthritis-associated interstitial lung disease

Rheumatoid arthritis (RA)-associated interstitial lung disease (RA-ILD) develops in ~20% of patients with RA. SKG mice, which are genetically prone to development of autoimmune arthritis, develop a pulmonary interstitial pneumonia that resembles human cellular and fibrotic nonspecific interstitial pneumonia. Nintedanib, a tyrosine kinase inhibitor approved for treatment of idiopathic pulmonary fibrosis, has been shown to reduce the decline in lung function. Therefore, we investigated the effect of nintedanib on development of pulmonary fibrosis and joint disease in female SKG mice with arthritis induced by intraperitoneal injection of zymosan (5 mg). Nintedanib (60 mg·kg-1·day-1 via oral gavage) was started 5 or 10 wk after injection of zymosan. Arthritis and lung fibrosis outcome measures were assessed after 6 wk of treatment with nintedanib. A significant reduction in lung collagen levels, determined by measuring hydroxyproline levels and staining for collagen, was observed after 6 wk in nintedanib-treated mice with established arthritis and lung disease. Early intervention with nintedanib significantly reduced development of arthritis based on joint assessment and high-resolution μ-CT. This study impacts the RA and ILD fields by facilitating identification of a therapeutic treatment that may improve both diseases. As this model replicates the characteristics of RA-ILD, the results may be translatable to the human disease.

Carbamylation/citrullination of IgG Fc in bronchiectasis, established RA with bronchiectasis and RA smokers: a potential risk factor for disease

Bronchiectasis (BR) and smoking are risk factors for rheumatoid arthritis (RA) development. The mechanisms by which smoking and BR trigger RA are unknown, but are associated with concurrent rheumatoid factor (RF) and anti-cyclic citrullinated peptide antibody (anti-CCP) positivity. Anti-carbamylated protein antibodies (anti-CarP) have also been observed in BR patients and can be induced by smoking. Given that RF only has one antigen, immunoglobulin G (IgG) we have suggested that post-translational modifications to the Fc region of the heavy chain of IgG (IgGH) are a potential explanation for the clustering of the RA-associated autoantibodies in RA.

Protein analysis was undertaken on 22 individuals. Four of the individuals had a diagnosis of BR at the time of protein analysis and subsequently developed RA up to 18 months following blood sampling. Four smoking RA patients and 4 patients with both BR and RA and 10 healthy controls were also studied.

We identified modified arginines (Arg) frequently in the variable region and CH3 domains of IgG in patients and control subjects alike, but only observed carbamylated Lys and/or citrullinated Arg modifications in the RF binding site of the IgG CH2 domain of 5/12 (41.7%) patients investigated (1 BR, 2 RA and 2 BRRA), but in no control subjects (0/10, 0%) p=0.02.

This is the first report of citrullination and carbamylation at the RF binding site of IgG in RA. These results point towards the concept of a universal antigen in RA, an antigen that is post-translationally modified at the Fc region of IgGH.

Fc region of IgG is citrullinated and carbamylated, and these PTMs can occur prior to the development of RAhttp://ow.ly/8ZDe30evfO4

Heightened autoantibody immune response to citrullinated calreticulin in bronchiectasis: Implications for rheumatoid arthritis

Calreticulin (CRT) and citrullinated (citCRT) are implicated in rheumatoid arthritis (RA) pathology. citCRT binds to RA shared epitopes (SE) on HLA-DR molecules with high affinity and triggers pro-inflammatory events in adjacent cells. The aim of the study was to detect the presence of citCRT prior to developing RA and evaluate if citCT is a target for autoantibodies in RA cohorts with and without lung disease. Antibodies were assessed by ELISA against native CRT, citCRT and general protein citrullination, in sera from 50 RA patients without lung disease, 122 bronchiectasis (BR) patients, 52 bronchiectasis patients with RA (BRRA), 87 asthma patients and 77 healthy controls (HC). Serum citCRT was detected by immunoblotting and mass spectrometry. Genomic DNA was genotyped for HLA-DRB1 alleles. Patients were assessed for DAS28, rheumatoid factor, and anti-cyclic citrullinated peptide antibodies. Extracellular citCRT was detected in BR patients sera prior to them developing RA. A citCRT SE binding peptide GEWKPR_261citQIDNPDYK was identified. Anti-CRT antibodies were observed in 18% of BR patients with or without RA. Anti-citCRT antibodies were observed in ∼35% of BR or RA patients, increasing to 58% in BRRA patients. In the RA alone patients 7/20 (35%) who were negative for RF and anti-CCP were anti-CRT antibody positive and had higher DAS28 scores than triple negative RA alone patients. Three of the four BR patients who developed RA over 18 months were anti-citCRT+ve SE^+ve. The detection of citCRT in BR and development of anti-citCRT in BR patients suggests citCRT antigens are early targets of antigenicity in these patients, especially in SE^+ve patients prior to the onset of RA.

Bronchiectasis Rheumatoid Overlap Syndrome Is an Independent Risk Factor for Mortality in Patients With Bronchiectasis: A Multicenter Cohort Study

BACKGROUND

This study assessed if bronchiectasis (BR) and rheumatoid arthritis (RA), when manifesting as an overlap syndrome (BROS), were associated with worse outcomes than other BR etiologies applying the Bronchiectasis Severity Index (BSI).

METHODS

Data were collected from the BSI databases of 1,716 adult patients with BR across six centers: Edinburgh, United Kingdom (608 patients); Dundee, United Kingdom (n = 286); Leuven, Belgium (n = 253); Monza, Italy (n = 201); Galway, Ireland (n = 242); and Newcastle, United Kingdom (n = 126). Patients were categorized as having BROS (those with RA and BR without interstitial lung disease), idiopathic BR, bronchiectasis-COPD overlap syndrome (BCOS), and "other" BR etiologies. Mortality rates, hospitalization, and exacerbation frequency were recorded.

RESULTS

A total of 147 patients with BROS (8.5% of the cohort) were identified. There was a statistically significant relationship between BROS and mortality, although this relationship was not associated with higher rates of BR exacerbations or BR-related hospitalizations. The mortality rate over a mean of 48 months was 9.3% for idiopathic BR, 8.6% in patients with other causes of BR, 18% for RA, and 28.5% for BCOS. Mortality was statistically higher in patients with BROS and BCOS compared with those with all other etiologies. The BSI scores were statistically but not clinically significantly higher in those with BROS compared with those with idiopathic BR (BSI mean, 7.7 vs 7.1, respectively; P < .05). Patients with BCOS had significantly higher BSI scores (mean, 10.4), Pseudomonas aeruginosa colonization rates (24%), and previous hospitalization rates (58%).

CONCLUSIONS

Both the BROS and BCOS groups have an excess of mortality. The mechanisms for this finding may be complex, but these data emphasize that these subgroups require additional study to understand this excess mortality.

Lung involvement in inflammatory rheumatic diseases

This chapter describes the involvement of the lung in systemic inflammatory joint disease (IJD) with a particular focus on rheumatoid arthritis, although the topics of pulmonary involvement in ankylosing spondylitis and psoriatic arthritis are also addressed. Interstitial lung disease is the most lethal pulmonary complication of IJD and the chapter describes recent advances in both our understanding of this complication and the therapeutic options that offer real hope for improved outcomes. Although less well recognised, airways disease is just as common and its association with IJD is described in some detail, with a section devoted to the recent surge in interest in bronchiectasis. Acute pulmonary infection is common in IJD and its management is reviewed in some detail. Although pleural disease is less common than it once was, its treatment is explored. We conclude by reviewing the relationship between the drug therapies employed in IJD and their effects on the lung.

Global impact of bronchiectasis and cystic fibrosis

EDUCATIONAL AIMS

To recognise the clinical and radiological presentation of the spectrum of diseases associated with bronchiectasis.To understand variation in the aetiology, microbiology and burden of bronchiectasis and cystic fibrosis across different global healthcare systems.

Bronchiectasis is the term used to refer to dilatation of the bronchi that is usually permanent and is associated with a clinical syndrome of cough, sputum production and recurrent respiratory infections. It can be caused by a range of inherited and acquired disorders, or may be idiopathic in nature. The most well recognised inherited disorder in Western countries is cystic fibrosis (CF), an autosomal recessive condition that leads to progressive bronchiectasis, bacterial infection and premature mortality. Both bronchiectasis due to CF and bronchiectasis due to other conditions are placing an increasing burden on healthcare systems internationally. Treatments for CF are becoming more effective leading to more adult patients with complex healthcare needs. Bronchiectasis not due to CF is becoming increasingly recognised, particularly in the elderly population. Recognition is important and can lead to identification of the underlying cause, appropriate treatment and improved quality of life. The disease is highly diverse in its presentation, requiring all respiratory physicians to have knowledge of the different "bronchiectasis syndromes". The most common aetiologies and presenting syndromes vary depending on geography, with nontuberculous mycobacterial disease predominating in some parts of North America, post-infectious and idiopathic disease predominating in Western Europe, and post-tuberculosis bronchiectasis dominating in South Asia and Eastern Europe. Ongoing global collaborative studies will greatly advance our understanding of the international impact of bronchiectasis and CF.

The lung in rheumatoid arthritis, cause or consequence?

PURPOSE OF REVIEW

Recent discoveries implicate the lungs as a possible extra-articular mucosal site for initiating rheumatoid arthritis-associated immunity.

RECENT FINDINGS

Individuals at risk for developing arthritis and patients with early untreated rheumatoid arthritis show signs of lung involvement on high-resolution computer tomography. Rheumatoid arthritis-associated antibodies are present in patients with respiratory complains such as bronchiectasis and unexplained dyspnea even in the absence of joint disease and might predict future development of rheumatoid arthritis in these patients. Rheumatoid arthritis-associated antibodies are detected in the sputum of individuals at risk for developing rheumatoid arthritis but not yet having disease. Signs of bronchial mucosal inflammation with germinal center formation and local production of antibodies have been described in patients with early untreated rheumatoid arthritis. Shared antigenic targets have been identified and characterized in the lungs and joints of rheumatoid arthritis patients.

SUMMARY

Recent findings support an important role for the lung as a mucosal extra-articular place were inflammation induced by external triggers (such as smoking) leads to tolerance break and generation of rheumatoid arthritis-specific immunity already before disease onset with only secondary targeting of the joints.

Bronchiectasis: Current Concepts in Pathogenesis, Immunology, and Microbiology

Bronchiectasis is a disorder of persistent lung inflammation and recurrent infection, defined by a common pathological end point: irreversible bronchial dilatation arrived at through diverse etiologies. This suggests an interplay between immunogenetic susceptibility, immune dysregulation, bacterial infection, and lung damage. The damaged epithelium impairs mucus removal and facilitates bacterial infection with increased cough, sputum production, and airflow obstruction. Lung infection is caused by respiratory bacterial and fungal pathogens, including Pseudomonas aeruginosa, Haemophilus, Aspergillus fumigatus, and nontuberculous mycobacteria. Recent studies have highlighted the relationship between the lung microbiota and microbial-pathogen niches. Disease may result from environments favoring interleukin-17-driven neutrophilia. Bronchiectasis may present in autoimmune disease, as well as conditions of immune dysregulation, such as combined variable immune deficiency, transporter associated with antigen processing-deficiency syndrome, and hyperimmunoglobulin E syndrome. Differences in prevalence across geography and ethnicity implicate an etiological mix of genetics and environment underpinning susceptibility.

Bronchiectasis is a Model for Chronic Bacterial Infection Inducing Autoimmunity in Rheumatoid Arthritis

Objective

To examine the potential of chronic severe bacterial infection to generate rheumatoid factor (RF) and anti–citrullinated protein antibodies (ACPAs), by studying patients with bronchiectasis (BR) alone and BR patients with rheumatoid arthritis (BR/RA).

Methods

We studied 122 patients with BR alone, 50 patients with BR/RA, and 50 RA patients without lung disease, as well as 87 patients with asthma and 79 healthy subjects as controls. RF levels were measured using an automated analyzer, and cyclic citrullinated peptide 2 (CCP‐2) was used to detect ACPAs. The fine specificities of citrullinated α‐enolase peptide 1 (CEP‐1), Cit‐vimentin, and Cit‐fibrinogen to their arginine‐containing control peptides (arginine‐containing α‐enolase peptide 1 [REP‐1], vimentin, and fibrinogen) were measured by enzyme‐linked immunosorbent assay.

Results

Among the BR patients and control subjects, 39% and 42%, respectively, were ever‐smokers. The frequency of RF positivity in serum was increased in BR patients compared with controls (25% versus 10%), as were the frequencies of antibodies to CCP‐2 (5% versus 0%), CEP‐1 (7% versus 4%), Cit‐vimentin (7% versus 4%), and Cit‐fibrinogen (12% versus 4%), although only the differences for RF and Cit‐fibrinogen were significant (P < 0.05). We observed a corresponding increase in the frequency of antibodies to the arginine‐containing control peptides in BR patients compared with controls (for REP‐1, 19% versus 4% [P < 0.01]; for vimentin, 16% versus 4% [P < 0.05]), demonstrating that the ACPA response in patients with BR is not citrulline specific. The lack of citrulline specificity was further confirmed by absorption studies. In BR/RA patients, all ACPA responses were highly citrulline specific.

Conclusion

Bronchiectasis is an unusual but potent model for the induction of autoimmunity in RA by bacterial infection in the lung. Our study suggests that the ACPA response is not citrulline specific during the early stages of tolerance breakdown but becomes more specific in patients with BR in whom BR/RA develops.

Signs of immune activation and local inflammation are present in the bronchial tissue of patients with untreated early rheumatoid arthritis

OBJECTIVES

Events in the lungs might contribute to generation of anticitrullinated protein antibodies (ACPA) in rheumatoid arthritis (RA). We investigated if signs of immune activation are present in bronchial biopsies and bronchoalveolar lavage (BAL) of patients with early-untreated RA without clinical signs of lung involvement.

METHODS

Twenty-four patients with RA with symptom duration <1 year and naïve to disease-modifying antirheumatic drugs were subjected to bronchoscopy where BAL and mucosal bronchial biopsies were retrieved. For comparison, 15 bronchial biopsies and 79 BAL samples from healthy volunteers were available. Histological examination was performed to evaluate lymphocyte infiltration, presence of immune cells (T and B cells, plasma cells, dendritic cells and macrophages) and immune activation markers. Cell composition of BAL samples was analysed by differential counting and T cell subsets by flow cytometry.

RESULTS

Lymphocyte infiltration was more frequently found in ACPA-positive patients (50%) as compared with ACPA-negative patients (17%) and controls (13%). Germinal centres, B cells and plasma cells were only found in ACPA-positive patients. The frequency of T cells in bronchial biopsies of patients with ACPA-positive RA was positively associated with expression of immune activation markers. BAL samples of patients with ACPA-positive, but not ACPA-negative, RA had significantly higher relative numbers of lymphocytes and expressed higher levels of activation markers compared with controls.

CONCLUSIONS

Signs of immune cell accumulation and activation are present both in the bronchial tissue and in BAL of untreated patients with early RA without concomitant lung disease, strengthening the role of the lung compartment as an important player in ACPA-positive RA.

Increased disease activity, severity and autoantibody positivity in rheumatoid arthritis patients with co-existent bronchiectasis

AIM

Patients with rheumatoid arthritis (RA) and co-existent bronchiectasis (BRRA) have a five-fold increased mortality compared to rheumatoid arthritis alone. Yet previous studies have found no difference in clinical and serological markers of RA disease severity between BRRA patients and RA alone. However, RA disease activity measures such as Disease Activity Score of 28 joints - C-reactive protein (DAS28-CRP) and anti-cyclic citrullinated peptide antibodies (anti-CCP) have not been studied, so we assessed these parameters in patients with BRRA and RA alone.

METHODS

BRRA patients (n = 53) had high-resolution computed tomography proven bronchiectasis without any interstitial lung disease and ≥ 2 respiratory infections/year. RA alone patients (n = 50) had no clinical or radiological evidence of lung disease. DAS28-CRP, rheumatoid factor (immunoglobulin M) and anti-CCP were measured in all patients, together with detailed clinical and radiology records.

RESULTS

In BRRA, bronchiectasis predated RA in 58% of patients. BRRA patients had higher DAS28 scores (3.51 vs. 2.59), higher levels of anti-CCP (89% vs. 46%) and rheumatoid factor (79% vs. 52%) (P = 0.003) compared to RA alone. Where hand and foot radiology findings were recorded, 29/37 BRRA (78%) and 13/30 (43%) RA alone had evidence of erosive change (P = 0.003). There were no significant differences between groups in smoking history or disease-modifying anti-rheumatic drug/biologic therapy.

CONCLUSIONS

Increased levels of RA disease activity, severity and RA autoantibodies are demonstrated in patients with RA and co-existent bronchiectasis compared to patients with RA alone, despite lower tobacco exposure. This study demonstrates that BRRA is a more severe systemic disease than RA alone.

Rheumatoid arthritis-associated autoantibodies in non-rheumatoid arthritis patients with mucosal inflammation: a case-control study

Introduction

Rheumatoid arthritis–associated autoantibodies (RA-AAB) can be present in serum years before clinical onset of rheumatoid arthritis (RA). It has been hypothesized that initiation of RA-AAB generation occurs at inflamed mucosal surfaces, such as in the oral cavity or lungs. The aim of this study was to assess systemic presence of RA-AAB in patients without RA who had oral or lung mucosal inflammation.

Methods

The presence of RA-AAB (immunoglobulin A [IgA] and IgG anti-cyclic citrullinated peptide 2 antibodies (anti-CCP2), IgM and IgA rheumatoid factor (RF), IgG anti-carbamylated protein antibodies and IgG and IgA anti-citrullinated peptide antibodies against fibrinogen, vimentin and enolase) were determined in sera of non-RA patients with periodontitis (PD, n = 114), bronchiectasis (BR, n = 80) or cystic fibrosis (CF, n = 41). Serum RA-AAB levels were compared with those of periodontally healthy controls (n = 36). Patients with established RA (n = 86) served as a reference group. Association of the diseases with RA-AAB seropositivity was assessed with a logistic regression model, adjusted for age, sex and smoking.

Results

Logistic regression analysis revealed that IgG anti-CCP seropositivity was associated with BR and RA, whereas the association with PD was borderline significant. IgA anti-CCP seropositivity was associated with CF and RA. IgM RF seropositivity was associated with RA, whereas the association with BR was borderline significant. IgA RF seropositivity was associated with CF and RA. Apart from an influence of smoking on IgA RF in patients with RA, there was no influence of age, sex or smoking on the association of RA-AAB seropositivity with the diseases. Anti-CarP levels were increased only in patients with RA. The same held for IgG reactivity against all investigated citrullinated peptides.

Conclusion

Although overall levels were low, RA-AAB seropositivity was associated with lung mucosal inflammation (BR and CF) and may be associated with oral mucosal inflammation (PD). To further determine whether mucosal inflammation functions as a site for induction of RA-AAB and precedes RA, longitudinal studies are necessary in which RA-AAB of specifically the IgA isotype should be assessed in inflamed mucosal tissues and/or in their inflammatory exudates.

Periodontitis and Rheumatoid Arthritis: What Do We Know?

BACKGROUND

Currently, in the field of rheumatology, there is much attention given towards the possible causality between periodontitis and rheumatoid arthritis (RA), specifically regarding the role of Porphyromonas gingivalis (Pg). This bacterium is unique, having a citrullinating enzyme. Antibodies against citrullinated proteins are rather specific for RA.

METHODS

Because causality is ultimately tested in longitudinal cohort studies which currently do not exist for periodontitis and RA, this commentary applied Bradford Hill criteria on the existing literature to assess causality as the most likely interpretation of this association.

CONCLUSIONS

From an epidemiologic point of view, patients with RA have a higher incidence of periodontal disease than individuals without RA. In addition, there is a dose-response pattern in the association between the severity of periodontitis and RA disease activity. There are indications that periodontitis precedes RA, but there is no evidence yet available to show that Pg plays a direct role in this temporal relationship. The role of the unique characteristic of citrullination by Pg remains unexplained. However, in animal models, citrullination by Pg plays a distinct role in the development and aggravation of experimental arthritis. Although the role of Pg in RA remains speculative, a causative role for periodontitis as a chronic inflammatory disease caused by infectious agents in RA seems biologically plausible.

Expression of citrulline and homocitrulline residues in the lungs of non-smokers and smokers: implications for autoimmunity in rheumatoid arthritis

Introduction

Smoking is a well-established risk factor for rheumatoid arthritis (RA), and it has been proposed that smoking-induced citrullination renders autoantigens immunogenic. To investigate this mechanism, we examined human lung tissue from 40 subjects with defined smoking status, with or without chronic obstructive pulmonary disease (COPD), and control tissues from other organs for citrullinated proteins and the deiminating enzymes peptidylarginine deiminase type-2 (PAD2) and -4 (PAD4).

Methods

Lung tissue samples, dissected from lobectomy specimens from 10 never smokers, 10 smokers without airflow limitation, 13 COPD smokers and eight COPD ex-smokers, and control tissue samples (spleen, skeletal muscle, liver, ovary, lymph node, kidney and heart), were analysed for citrullinated proteins, PAD2 and PAD4 by immunoblotting. Citrulline and homocitrulline residues in enolase and vimentin were analysed by partial purification by gel electrophoresis followed by mass spectrometry in 12 of the lung samples and one from each control tissues. Band intensities were scored semi-quantitatively and analysed by two-tailed Mann-Whitney T-test.

Results

Within the lung tissue samples, citrullinated proteins, PAD2 and PAD4 were found in all samples, with an increase in citrullination in COPD (P = 0.039), but minimal difference between smokers and non-smokers (P = 0.77). Citrullination was also detected at lower levels in the tissues from other organs, principally in lymph node, kidney and skeletal muscle. Mass spectrometry of the lung samples showed that vimentin was citrullinated at positions 71, 304, 346, 410 and 450 in non-smokers and smokers both with and without COPD. A homocitrulline at position 104 was found in four out of six COPD samples and one out of six non-COPD. Citrulline-450 was also found in three of the control tissues. There were no citrulline or homocitrulline residues demonstrated in α-enolase.

Conclusions

We have shown evidence of citrullination of vimentin, a major autoantigen in RA, in both non-smokers and smokers. The increase in citrullinated proteins in COPD suggests that citrullination in the lungs of smokers is mainly due to inflammation. The ubiquity of citrullination of vimentin in the lungs and other tissues suggests that the relationship between smoking and autoimmunity in RA may be more complex than previously thought.

Electronic supplementary material

The online version of this article (doi:10.1186/s13075-015-0520-x) contains supplementary material, which is available to authorized users.