Long-term macrolide antibiotic therapy in the treatment of chronic small airway disease clinically mimicking diffuse panbronchiolitis

Constrictive (Obliterative) Bronchiolitis as Presenting Manifestation of Connective Tissue Diseases

BACKGROUND

Constrictive (obliterative) bronchiolitis (CB) is an uncommon form of obstructive lung disease that can occur in patients with identifiable causes including connective tissue diseases (CTDs) as a form of lung involvement. We explored whether CB can be the presenting manifestation of CTD.

METHODS

We identified 44 patients with cryptogenic CB and examined the presenting clinical, laboratory, and radiologic features, as well as their clinical course.

RESULTS

The mean age at presentation was 60.5 (SD, 13.8) years and included 38 women (86%); 32 (73%) were never smokers. All patients presented for evaluation of dyspnea, commonly associated with cough. An obstructive pattern on pulmonary function testing was demonstrated in 86% of patients. On chest high-resolution computed tomography, nearly all patients manifested a mosaic attenuation pattern with air trapping on expiratory views, characteristic of CB. Bronchoscopic lung biopsy (n = 10) was usually nondiagnostic (90%), whereas all 5 surgical lung biopsies yielded evidence of CB. Serologic testing for CTD was positive in 19 patients (43%) and most commonly included antinuclear antibody, rheumatoid factor, and anti-cyclic citrullinated antibodies. Seven of these patients with positive serologic results were eventually diagnosed to have CTD. Connective tissue diseases included rheumatoid arthritis in 4 patients, Sjögren syndrome in 2, and undifferentiated CTD in 1 patient.

CONCLUSIONS

Nearly one-half of patients with cryptogenic CB manifest positive CTD serology, and some of these patients have CTD not previously diagnosed. These results suggest that CB can be the presenting manifestation of a CTD.

Macrolides for diffuse panbronchiolitis

BACKGROUND

Diffuse panbronchiolitis (DPB) is a chronic airways disease predominantly affecting East Asians. Macrolides, a class of antibiotics, have been used as the main treatment for DPB, based on evidence from retrospective and non-randomised studies.

OBJECTIVES

To assess the efficacy and safety of macrolides for DPB.

SEARCH METHODS

We searched CENTRAL (2014, Issue 6), MEDLINE (1966 to July week 1, 2014), EMBASE (1974 to July 2014), Chinese Biomedical Literature Database (CBM) (1978 to July 2014), China National Knowledge Infrastructure (CNKI) (1974 to July 2014), KoreaMed (1997 to July 2014) and Database of Japana Centra Revuo Medicina (1983 to July 2014).

SELECTION CRITERIA

Randomised controlled trials (RCTs) or quasi-RCTs assessing the effect of macrolides for DPB.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed study quality and subsequent risk of bias according to The Cochrane Collaboration's tool for assessing risk of bias. The primary outcomes were five-year survival rate, lung function and clinical response. We used risk ratios (RR) for individual trial results in the data analysis and measured all outcomes with 95% confidence intervals (CI).

MAIN RESULTS

Only one RCT (19 participants) with significant methodological limitations was included in this review. It found that the computerised tomography images of all participants treated with a long-term, low-dose macrolide (erythromycin) improved from baseline, while the images of 71.4% of participants in the control group (with no treatment) worsened and 28.6% remained unchanged. Adverse effects were not reported. This review was previously published in 2010 and 2013. For this 2014 update, we identified no new trials for inclusion or exclusion.

AUTHORS' CONCLUSIONS

There is little evidence for macrolides in the treatment of DPB. We are therefore unable to make any new recommendations. It may be reasonable to use low-dose macrolides soon after diagnosis is made and to continue this treatment for at least six months, according to current guidelines.

The effect of azithromycin in adults with stable neutrophilic COPD: a double blind randomised, placebo controlled trial

Background

Chronic Obstructive Pulmonary Disease (COPD) is a progressive airway disease characterised by neutrophilic airway inflammation or bronchitis. Neutrophilic bronchitis is associated with both bacterial colonisation and lung function decline and is common in exacerbations of COPD. Despite current available therapies to control inflammation, neutrophilic bronchitis remains common. This study tested the hypothesis that azithromycin treatment, as an add-on to standard medication, would significantly reduce airway neutrophil and neutrophils chemokine (CXCL8) levels, as well as bacterial load. We conducted a randomised, double-blind, placebo-controlled study in COPD participants with stable neutrophilic bronchitis.

Methods

Eligible participants (n = 30) were randomised to azithromycin 250 mg daily or placebo for 12 weeks in addition to their standard respiratory medications. Sputum was induced at screening, randomisation and monthly for a 12 week treatment period and processed for differential cell counts, CXCL8 and neutrophil elastase assessment. Quantitative bacteriology was assessed in sputum samples at randomisation and the end of treatment visit. Severe exacerbations where symptoms increased requiring unscheduled treatment were recorded during the 12 week treatment period and for 14 weeks following treatment. A sub-group of participants underwent chest computed tomography scans (n = 15).

Results

Nine participants with neutrophilic bronchitis had a potentially pathogenic bacteria isolated and the median total bacterial load of all participants was 5.22×10⁷ cfu/mL. Azithromycin treatment resulted in a non-significant reduction in sputum neutrophil proportion, CXCL8 levels and bacterial load. The mean severe exacerbation rate was 0.33 per person per 26 weeks in the azithromycin group compared to 0.93 exacerbations per person in the placebo group (incidence rate ratio (95%CI): 0.37 (0.11,1.21), p = 0.062). For participants who underwent chest CT scans, no alterations were observed.

Conclusions

In stable COPD with neutrophilic bronchitis, add-on azithromycin therapy showed a trend to reduced severe exacerbations sputum neutrophils, CXCL8 levels and bacterial load. Future studies with a larger sample size are warranted.

Trial Registration

Australian New Zealand Clinical Trials Registry ACTRN12609000259246

Macrolides for diffuse panbronchiolitis

BACKGROUND

Diffuse panbronchiolitis (DPB) is a chronic airways disease predominantly affecting East Asians. Macrolides, a class of antibiotics, have been used as the main treatment for DPB, based on evidence from retrospective and non-randomised studies.

OBJECTIVES

To assess the efficacy and safety of macrolides for DPB.

SEARCH METHODS

We searched CENTRAL 2012, Issue 7, MEDLINE (1966 to July week 2, 2012), EMBASE (1974 to July 2012), Chinese Biomedical Literature Database (CBM) (1978 to July 2012), China National Knowledge Infrastructure (CNKI) (1974 to July 2012), KoreaMed (1997 to July 2012) and Database of Japana Centra Revuo Medicina (1983 to July 2012).

SELECTION CRITERIA

Randomised controlled trials (RCTs) or quasi-RCTs assessing the effect of macrolides for DPB.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed study quality and subsequent risk of bias according to the Cochrane Collaboration's tool for assessing risk of bias. The primary outcomes were five-year survival rate, lung function and clinical response. We used risk ratios (RR) for individual trial results in the data analysis and measured all outcomes with 95% confidence intervals (CI).

MAIN RESULTS

Only one RCT (19 participants) with significant methodological limitations was included in this review. It found that the computerised tomography images of all participants treated with a long-term, low-dose macrolide (erythromycin) improved from baseline, while the images of 71.4% of participants in the control group (with no treatment) worsened and 28.6% remained unchanged. Adverse effects were not reported.

AUTHORS' CONCLUSIONS

There is little evidence for macrolides in the treatment of DPB. We are therefore unable to make any new recommendations. It may be reasonable to use low-dose macrolides soon after diagnosis is made and to continue this treatment for at least six months, according to current guidelines.

Macrolides for diffuse panbronchiolitis

BACKGROUND

Diffuse panbronchiolitis (DPB) is a chronic airways disease predominantly affecting East Asians. Macrolides, a class of antibiotics, have been used as the main treatment for DPB, based on evidence from retrospective and non-randomised studies.

OBJECTIVES

To assess the efficacy and safety of macrolides for DPB.

SEARCH STRATEGY

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2010, issue 1), which contains the Cochrane Acute Respiratory Infections Group's Specialised Register, MEDLINE (1966 to April 2010), EMBASE (1974 to April 2010), Chinese Biomedical Literature Database (CBM) (1978 to April 2010), China National Knowledge Infrastructure (CNKI) (1974 to April 2010), KoreaMed (1997 to April 2010) and Database of Japana Centra Revuo Medicina (1983 to April 2010).

SELECTION CRITERIA

Randomised controlled trials (RCTs) or quasi-RCTs assessing the effect of macrolides for DPB.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed study quality and subsequent risk of bias according to the Cochrane Collaboration's tool for assessing risk of bias. The primary outcomes were five-year survival rate, lung function and clinical response. We used risk ratios (RR) for individual trial results in the data analysis and measured all outcomes with 95% confidence intervals (CI).

MAIN RESULTS

Only one RCT (19 participants) with significant methodological limitations was included in this review. It found that the computerised tomography images of all participants treated with a long-term, low-dose macrolide (erythromycin) improved from baseline, while the images of 71.4% of participants in the control group (with no treatment) worsened and 28.6% remained unchanged. Adverse effects were not reported.

AUTHORS' CONCLUSIONS

There is little evidence for macrolides in the treatment of DPB. We are therefore unable to make any new recommendations. It may be reasonable to use low-dose macrolides soon after diagnosis is made and to continue this treatment for at least six months, according to current guidelines.

Mechanisms of action and clinical application of macrolides as immunomodulatory medications

Macrolides have diverse biological activities and an ability to modulate inflammation and immunity in eukaryotes without affecting homeostatic immunity. These properties have led to their long-term use in treating neutrophil-dominated inflammation in diffuse panbronchiolitis, bronchiectasis, rhinosinusitis, and cystic fibrosis. These immunomodulatory activities appear to be polymodal, but evidence suggests that many of these effects are due to inhibition of extracellular signal-regulated kinase 1/2 (ERK1/2) phosphorylation and nuclear factor kappa B (NF-kappaB) activation. Macrolides accumulate within cells, suggesting that they may associate with receptors or carriers responsible for the regulation of cell cycle and immunity. A concern is that long-term use of macrolides increases the emergence of antimicrobial resistance. Nonantimicrobial macrolides are now in development as potential immunomodulatory therapies.

Pathology of small airways disease

CONTEXT

The term small airways disease encompasses a generally poorly understood group of lung diseases that may arise primarily within the small airways or secondarily from diseases primarily affecting the bronchi or lung parenchyma. Their histology may be confusing; however, because treatments and prognoses vary, correct pathologic diagnosis is important.

OBJECTIVE

To present a nonexhaustive review of the pathology of primary and secondary small airways diseases, including small airways disease related to tobacco; to various other exposures, including mineral dusts; to diseases involving other areas of the lung with secondary bronchiolar involvement; and to recently described bronchiolitic disorders.

DATA SOURCES

Current literature is reviewed.

CONCLUSIONS

Small airways diseases include a wide variety of diseases of which the pathologist must consider. Uncommon conditions such as diffuse idiopathic neuroendocrine cell hyperplasia and diffuse panbronchiolitis may show relatively specific diagnostic features histologically; however, most small airways diseases exhibit nonspecific histologic features. Conditions not considered primary pulmonary diseases, such as collagen vascular diseases, bone marrow transplantation, and inflammatory bowel disease, must also be considered in patients with small airways changes histologically. Clinical and radiologic correlation is important for obtaining the best possible diagnosis.

Small Airways Disease

Small airways diseases are best defined pathologically as a diverse group of conditions that primarily involve bronchioles and acartilagenous airways 2 mm or less in diameter, which include membranous bronchioles, respiratory bronchioles, and alveolar ducts. Small airways can be involved with disease primarily or secondarily. The concept of small airways disease varies among specialties, with clinicians generally considering them in terms of terminal airway changes causing airflow obstruction, radiologists considering them in the context of direct signs and indirect signs identified on high-resolution computed tomography scans, and pathologists evaluating them based entirely or almost entirely on the histologic changes present in the bronchioles, with or without associated changes involving bronchi and alveoli. The histologic features of small airways diseases may be confusing because they overlap. There may be incomplete assessment of the histologic process with limited biopsy. Other disease processes may occur along with a small airways disease, and may obscure or confound its histologic features. This article focuses on the histologic changes diagnostic of a variety of primary and secondary small airways diseases. Because the histologic features involve bronchioles, gross findings are often minimal and/or nonspecific. The article provides a nonexhaustive examination of conditions and diseases involving the small airways, focusing on the microscopic features, with emphasis on the limitations of histologic diagnosis and differential diagnosis.

Diffuse lymphoplasmacytic bronchiolitis in cartilage-hair hypoplasia

Three children with cartilage-hair hypoplasia presented with chronic obstructive symptoms and bronchiolar wall thickening on high-resolution computed tomography scanning. In all children, surgical lung biopsy demonstrated diffuse dilated lymphoplasmacytic bronchiolitis. The bronchiolar wall was infiltrated by a lymphocyte sheath with plasma cell differentiation and dispersed secondary follicles. Clarithromycin substantially improved respiratory symptoms and pulmonary function, allowing children to return home.

Sarcoidosis in the setting of idiopathic chronic bronchiolitis with airway colonization from P. aeruginosa: treatment with low-dose macrolides

It has long been suggested that infectious agents may trigger sarcoidosis through their infectious or antigenic properties. A patient with airway colonization from P. aeruginosa in the setting of idiopathic bronchiolitis (IB) mimicking diffuse panbronchiolitis (DPB) developed sarcoidosis. Impressive clinical and radiological improvement of both bronchiolitis and sarcoidosis features was achieved with a one-year treatment with low-dose erythromycin, thus suggesting a possible link between the two conditions in this specific case. Pathogenic hypotheses and therapeutic implications are specifically discussed.