Patients with nontuberculous mycobacterial lung disease exhibit unique body and immune phenotypes

Intermittent antibiotic therapy for nodular bronchiectatic Mycobacterium avium complex lung disease

RATIONALE

Although intermittent, three-times-weekly therapy is recommended for the initial treatment of noncavitary nodular bronchiectatic Mycobacterium avium complex (MAC) lung disease, supporting data are limited.

OBJECTIVES

To evaluate the clinical efficacy of intermittent therapy compared with daily therapy for nodular bronchiectatic MAC lung disease.

METHODS

A retrospective cohort study of 217 patients with treatment-naive noncavitary nodular bronchiectatic MAC lung disease. All patients received either daily (n = 99) or intermittent therapy (n = 118) that included clarithromycin or azithromycin, rifampin, and ethambutol.

MEASUREMENTS AND MAIN RESULTS

Modification of the initial antibiotic therapy occurred more frequently in the daily therapy group than in the intermittent therapy group (46 vs. 21%; P < 0.001); in particular, ethambutol was more frequently discontinued in the daily therapy group than in the intermittent therapy group (24 vs. 1%; P ≤ 0.001). However, the rates of symptomatic improvement, radiographic improvement, and sputum culture conversion were not different between the two groups (daily therapy vs. intermittent therapy: 75 vs. 82%, P = 0.181; 68 vs. 73%, P = 0.402; 76 vs. 67%, P = 0.154, respectively). In addition, the adjusted proportion of sputum culture conversion was similar between the daily therapy (71.3%; 95% confidence interval, 59.1-81.1%) and the intermittent therapy groups (73.6%; 95% confidence interval, 62.9-82.2%; P = 0.785).

CONCLUSIONS

These results suggest that intermittent three-times-weekly therapy with a macrolide, rifampin, and ethambutol is a reasonable initial treatment regimen for patients with noncavitary nodular bronchiectatic MAC lung disease. Clinical trial registered with www.clinicaltrials.gov (NCT 00970801).

Risk of mycobacterial infections associated with rheumatoid arthritis in Ontario, Canada

OBJECTIVE

Patients with rheumatoid arthritis (RA) are at increased risk of TB. Little is known about the risk of nontuberculous mycobacteria (NTM) disease in these patients. We sought to ascertain the rate of NTM infection and TB in all residents of Ontario, Canada, with and without RA.

METHODS

In a cohort study, all Ontarians aged ≥ 15 years in January 2001 were followed until December 2010. Individuals with RA were identified using a validated algorithm to search hospitalization and physician billing claims. We linked Public Health Ontario Laboratory data to identify all cases of laboratory-confirmed TB and NTM disease. Analysis was performed using Cox proportional hazards regression.

RESULTS

We identified 113,558 Ontarians with RA and 9,760,075 Ontarians without RA. Relative to the non-RA group, adjusted hazard ratios (HRs) and 95% CIs for TB (1.92, [1.50-2.47]) and NTM disease (2.07, [1.84-2.32]) demonstrated increased risks in the RA group. Among those with RA, per 100,000 person-years, NTM disease (HR, 41.6; 95% CI, 37.1-46.5) was more common than TB (HR, 8.5; 95% CI, 6.5-10.8). After full adjustment, people with RA who developed NTM disease were 1.81 times as likely to die than uninfected people with RA.

CONCLUSIONS

Mycobacterial infections are more common in Ontarians with RA, with NTM disease more likely than TB. NTM disease is associated with an increased risk of death in patients with RA. Given the rising rates of NTM disease worldwide, determining whether this risk is due to the use of immunosuppressive medications vs RA itself is an important objective for future research.

Pathogenesis and risk factors for nontuberculous mycobacterial lung disease

Nontuberculous mycobacteria (NTM) infections are broadly classified as skin and soft tissue infections, isolated lung disease, and visceral or disseminated disease. The degree of underlying immune abnormalities varies between each classification. Skin and soft tissue infections are usually the result of iatrogenic or accidental inoculation of NTM in otherwise normal hosts. Visceral and disseminated NTM disease invariably occurs in individuals with more severe immunosuppression. Although the focus of this article is to discuss the pathogenesis of NTM lung disease, the risk factors of visceral/disseminated NTM disease are also summarized, as they provide insights into host-defense mechanisms against these organisms.

[Respiratory manifestations of Marfan's syndrome]

Marfan's syndrome is a rare genetic disorder caused by a mutation of the gene FBN1, coding for the protein fibrillin-1. Cardiovascular, musculoskeletal and ophthalmic manifestations are the most commonly observed, but minor diagnostic criteria also include pulmonary manifestations. Pneumothorax, frequently relapsing, affects 5 to 11% of patients. Rib cage abnormalities (pectus excavatum or pectus carinatum) and apical blebs may contribute to their occurrence. Treatment does not require any specific procedure but there is an increased risk of recurrence. Pectus excavatum affects up to 60% of the patients, without any functional impairment in most cases. Surgery may be required (using the Nuss procedure) in case of cardiovascular or psychological symptoms. Marfan's syndrome is frequently associated with obstructive sleep apnoea, which may itself contribute to aortic dilatation. Some studies suggest a potential role of craniofacial abnormalities in the pathogenesis of sleep apnea in these patients. Pulmonologists should consider Marfan's syndrome when treating patients for recurrent spontaneous pneumothorax or rib cage abnormalities, since early detection of cardiac abnormalities improves the prognosis significantly.

Respiratory review of 2014: tuberculosis and nontuberculous mycobacterial pulmonary disease

Since tuberculosis (TB) remains a major global health concern and the incidence of multi-drug resistant (MDR)-TB is increasing globally, new modalities for the detection of TB and drug resistant TB are needed to improve TB control. The Xpert MTB/RIF test can be a valuable new tool for early detection of TB and rifampicin resistance, with a high sensitivity and specificity. Late-generation fluoroquinolones, levofloxacin, and moxifloxacin, which are the principal drugs for the treatment of MDR-TB, show equally high efficacy and safety. Systemic steroids may reduce the overall TB mortality attributable to all forms of TB across all organ systems, although inhaled corticosteroids can increase the risk of TB development. Although fixed dose combinations were expected to reduce the risk of drug resistance and increase drug compliance, a recent meta-analysis found that they might actually increase the risk of relapse and treatment failure. Regarding treatment duration, patients with cavitation and culture positivity at 2 months of TB treatment may require more than 6 months of standard treatment. New anti-TB drugs, such as linezolid, bedaquiline, and delamanid, could improve the outcomes in drug-resistant TB. Nontuberculous mycobacterial lung disease has typical clinical and immunological phenotypes. Mycobacterial genotyping may predict disease progression, and whole genome sequencing may reveal the transmission of Mycobacterium abscessus. In refractory Mycobacterium avium complex lung disease, a moxifloxacin-containing regimen was expected to improve the treatment outcome.

Highlight on advances in nontuberculous mycobacterial disease in North America

Nontuberculous mycobacteria (NTM) are ubiquitous in the environment and exist as an important cause of pulmonary infections in humans. Pulmonary involvement is the most common disease manifestation of NTM and the incidence of NTM is growing in North America. Susceptibility to NTM infection is incompletely understood; therefore preventative tools are not well defined. Treatment of pulmonary nontuberculous mycobacterial (NTM) infection is difficult and entails multiple antibiotics and an extended treatment course. Also, there is a considerable variation in treatment management that should be considered before initiating treatment. We highlight the new findings in the epidemiology diagnosis and treatment of mycobacterial infections. We debate new advances regarding NTM infection in cystic fibrosis patients and solid organ transplant recipients. Finally, we introduce a new epidemiologic model for NTM disease based on virulence-exposure-host factors.

Diagnosis of pulmonary tuberculosis and nontuberculous mycobacterial lung disease in Korea

The recovery of nontuberculous mycobacteria (NTM) from respiratory specimens and the number of patients with NTM lung disease have been rapidly increasing in Korea. An early differential diagnosis of NTM lung disease from pulmonary tuberculosis (TB) is important, as the therapeutic regimen differs from that of pulmonary TB, and it is not necessary to track the contacts of patients with NTM lung disease. However, differentiating NTM lung disease from pulmonary TB remains difficult, because the clinical presentations of the two diseases are similar and a definite diagnosis of NTM lung disease based on sputum culture takes time. This review focuses on the changing epidemiology, clinical and radiographic manifestation, and laboratory diagnosis of pulmonary TB and NTM lung disease in Korea.

Changes in serum immunomolecules during antibiotic therapy for Mycobacterium avium complex lung disease

Little information is available regarding changes in immune status for patients with Mycobacterium avium complex (MAC) lung disease during antibiotic therapy. Serum immunomolecules from 42 patients with MAC lung disease were assayed comparatively using an array-based system according to (i) patients with MAC lung disease at the time of diagnosis versus healthy controls and (ii) alterations after 12 months of antibiotic therapy in the MAC lung disease group. In addition, cytokine analyses were performed to determine whether cytokine responses were associated specifically with the disease phenotype, treatment outcome and aetiological agent. Notably, the serum concentrations of type 1 cytokine-associated molecules, such as CD40L, interferon (IFN)-γ, interleukin (IL)-8 and IL-23, were decreased significantly in patients at the time of diagnosis, suggesting that these molecules may serve as indicators of host susceptibility to MAC disease. Although the overall serum level of T helper type 1 (Th1)-related molecules, such as CD40L and IFN-γ, was restored after treatment, Th17-related cytokines, such as IL-17 and IL-23, were down-regulated significantly at 12 months post-treatment compared to pretreatment. Furthermore, these cytokine patterns differed among patient subgroups. Decreased serum concentrations of IL-17 and/or IL-23 were associated with failure of sputum conversion, the fibrocavitary disease phenotype and M. intracellulare lung disease. Thus, the reciprocal balance between Th1 and Th17 immunity during antibiotic therapy for MAC lung disease is critical for dictating the treatment response. In conclusion, a low level of Th1-related immunomolecules may perpetuate MAC lung disease, and the serum concentrations of Th17-related cytokines can reflect the treatment outcome, disease phenotype and aetiological agent.

Complement C4 deficiency--a plausible risk factor for non-tuberculous mycobacteria (NTM) infection in apparently immunocompetent patients

Background

Non-tuberculous mycobacteria (NTM) are ubiquitous in the environment and they infect mainly persons with underlying pulmonary diseases but also previously healthy elderly women. Defects in host resistance that lead to pulmonary infections by NTM are relatively unknown. A few genetic defects have been associated with both pulmonary and disseminated mycobacterial infections. Rare disseminated NTM infections have been associated with genetic defects in T-cell mediated immunity and in cytokine signaling in families. We investigated whether there was an association between NTM infections and deficiencies of complement components C4A or C4B that are encoded by major histocompatibility complex (MHC).

Methods

50 adult patients with a positive NTM culture with symptoms and findings of a NTM disease were recruited. Patients' clinical history was collected and symptoms and clinical findings were categorized according to 2007 diagnostic criteria of The American Thoracic Society (ATS). To investigate the deficiencies of complement, C4A and C4B gene copy numbers and phenotype frequencies of the C4 allotypes were analyzed. Unselected, healthy, 149 Finnish adults were used as controls.

Results

NTM patients had more often C4 deficiencies (C4A or C4B) than controls (36/50 [72%] vs 83/149 [56%], OR = 2.05, 95%CI = 1.019–4.105, p = 0.042). C4 deficiencies for female NTM patients were more common than for controls (29/36 [81%] vs 55/100 [55%], OR = 3.39, 95% CI = 1.358–8.460, p = 0.007). C4 deficiences seemed not to be related to any specific underlying disease or C4 phenotype.

Conclusions

C4 deficiency may be a risk factor for NTM infection in especially elderly female patients.

The impact of low subcutaneous fat in patients with nontuberculous mycobacterial lung disease

BACKGROUND

Nontuberculous mycobacteria (NTM) are pathogens that cause chronic respiratory disease, even in immunocompetent patients. We hypothesized that low subcutaneous fat is a predisposing factor for NTM lung disease.

METHODS

Following a retrospective review of medical records from between 2005 and 2012, a total of 148 patients with NTM lung disease and 142 age- and sex-matched controls were enrolled. We evaluated subcutaneous fat using chest computed tomography (CT) scans at the midpole level of the left kidney.

RESULTS

The median age of the patients was 62 years and 60.8 % were female. Approximately 71 % were classified into a nodular bronchiectatic group. The patient group had significantly less subcutaneous fat than the control group (39.3 vs. 53.0 cm(2), p = 0.001). Patients with both localized disease (43.5 vs. 53.0 cm(2), p = 0.042) and extensive disease (35.9 vs. 53.0 cm(2), p < 0.0001) had less subcutaneous fat compared with the control group. No difference in subcutaneous fat was observed with respect to the increasing bacterial load in sputum (p = 0.246). In 20 patients with prominent disease progression during the follow-up period, no significant difference was observed between subcutaneous fat at the initial diagnosis and that at the follow-up CT (36.2 vs. 42.0 cm(2), p = 0.47).

CONCLUSION

Our results suggest that lower subcutaneous fat may contribute to host susceptibility to NTM lung disease.

Nutritional indicators are correlated with the radiological severity score in patients with Mycobacterium avium complex pulmonary disease: a cross-sectional study

OBJECTIVE

Body weight loss in patients with Mycobacterium avium complex (MAC) pulmonary disease can be fatal. The administration of nutritional supplements should be an important component in the treatment of this disease. Objective data regarding the association between the nutritional status and disease severity have not been reported. This cross-sectional study aimed to compare the nutritional status and radiological severity scores in MAC pulmonary disease patients.

METHODS

We retrospectively reviewed the records of 40 patients who were admitted to our institution for the treatment of MAC pulmonary disease between July 2008 and July 2010. Nutritional indices, including the ideal body weight ratio, triceps skinfold, mid-upper arm muscle circumference, and percentage of predicted resting energy expenditure, were compared with the radiological severity scores. Quantitative values of the extent of nodules, infiltration shadows, cavities, and bronchiectasis on the computed tomography scans were used to evaluate the radiological severity scores.

RESULTS

The patients suffered from a significantly decreased percentage of ideal body weight, body fat and muscle mass. The average radiological score was 17.6±8.4 points. The percentage of ideal body weight (p<0.001), percentage of triceps skinfold (p<0.001) and percentage of mid-upper arm muscle circumference (p<0.002) were negatively correlated with the radiological scores, while the percentage of the predicted resting energy expenditure (p<0.001) was positively correlated with the scores.

CONCLUSION

A poor nutritional status is common in patients with progressive MAC pulmonary disease, which supports the hypothesis that aggressive nutritional interventions are indicated in the treatment of this disease.

Phenotypic, immunologic, and clinical characteristics of patients with nontuberculous mycobacterial lung disease in Korea

Background

This study aimed to elucidate the phenotypic, immunologic, and clinical characteristics of Korean patients with nontuberculous mycobacterial (NTM) lung disease and compare them with non-NTM bronchiectasis (BE) patients.

Methods

We prospectively recruited patients between 20 and 80 years of age who had nodular BE type NTM lung disease. Phenotypic, immunologic, and clinical characteristics were evaluated through physical examination, laboratory tests, pulmonary function tests, and radiographic examinations. Questionnaires were also answered. The results of the evaluations were compared with the results of non-NTM BE patients.

Results

A total of 84 patients with NTM lung disease and 47 non-NTM BE patients participated in the study. Mycobacterium avium complex lung disease and M. abscessus lung disease were most common. Patients with NTM lung disease had lower body mass index than non-NTM BE patients. Scoliosis was observed more frequently in patients with NTM lung disease than in non-NTM BE patients.

Conclusions

Significant similarities were seen between Korean patients with NTM lung disease and patients from other countries. Differences in phenotypic and clinical characteristics between NTM lung disease and non-NTM BE patients suggest differences in the immunopathogenesis of NTM lung disease and non-NTM BE.

Trial registration information

ClinicalTrials.gov Registration number; NCT01616745

Serodiagnosis of Mycobacterium avium complex and Mycobacterium abscessus complex pulmonary disease by use of IgA antibodies to glycopeptidolipid core antigen

An enzyme immunoassay kit that detects serum IgA antibody reacting to glycopeptidolipid core antigen derived from Mycobacterium avium complex (MAC) was not useful for differentiating MAC pulmonary disease (PD) from Mycobacterium abscessus complex PD (MAB-PD). However, this assay could be useful for differentiating MAC- and MAB-PD from pulmonary tuberculosis. (This study has been registered at ClinicalTrials.gov under registration no. NCT00970801.).

Adiponectin in inflammatory and immune-mediated diseases

Circulating levels of adiponectin (APN) are reduced in obesity and associated comorbidities, with inflammation playing an important role in downregulating APN production. In contrast to obesity and metabolic disease, elevated systemic and local levels of APN are present in patients with inflammatory and immune-mediated diseases, including autoimmune and pulmonary conditions, heart and kidney failure, viral hepatitis, organ transplantation and perhaps critical illness. A positive association between inflammation and APN is usually reported in inflammatory/immune pathologies, in contrast with the negative correlation typical of metabolic disease. This review discusses the role of APN in modulation of inflammation and immunity and the potential mechanisms leading to increased levels of APN in inflammatory/immune diseases, including modification of adipose tissue physiology; relative contribution of different tissues and adipose depots; hormonal, pharmacological, nutritional and life style factors; the potential contribution of the microbiota as well as the role of altered APN clearance and release from T-cadherin-associated tissue reservoirs. Potential reasons for some of the apparently contradictory findings on the role of APN as a modulator of immunity and inflammation are also discussed, including a comparison of types of recombinant APN used for in vitro studies and strain-dependent differences in the phenotype of APN KO mice.

Patients with nontuberculous mycobacterial lung disease exhibit unique body and immune phenotypes

RATIONALE

Among patients with nontuberculous mycobacterial lung disease is a subset of previously healthy women with a slender body morphotype, often with scoliosis and/or pectus excavatum. We hypothesize that unidentified factors predispose these individuals to pulmonary nontuberculous mycobacterial disease.

OBJECTIVES

To compare body morphotype, serum adipokine levels, and whole-blood cytokine responses of patients with pulmonary nontuberculous mycobacteria (pNTM) with contemporary control subjects who are well matched demographically.

METHODS

We enrolled 103 patients with pNTM and 101 uninfected control subjects of similar demographics. Body mass index and body fat were quantified. All patients with pNTM and a subset of control subjects were evaluated for scoliosis and pectus excavatum. Serum leptin and adiponectin were measured. Specific cytokines important to host-defense against mycobacteria were measured in whole blood before and after stimulation.

MEASUREMENTS AND MAIN RESULTS

Patients with pNTM and control subjects were well matched for age, gender, and race. Patients with pNTM had significantly lower body mass index and body fat and were significantly taller than control subjects. Scoliosis and pectus excavatum were significantly more prevalent in patients with pNTM. The normal relationships between the adipokines and body fat were lost in the patients with pNTM, a novel finding. IFN-γ and IL-10 levels were significantly suppressed in stimulated whole blood of patients with pNTM.

CONCLUSIONS

This is the first study to comprehensively compare body morphotype, adipokines, and cytokine responses between patients with NTM lung disease and demographically matched controls. Our findings suggest a novel, predisposing immunophenotype that should be mechanistically defined.