Identification of Host Susceptibility Factors and Development of Biomarkers for Diagnosis, Prognosis and Treatment of Nontuberculous Mycobacterial Lung Disease

The incidence of pulmonary disease caused by nontuberculous mycobacteria (NTM) has been increasing, and a substantial proportion of these patients have no preexisting lung disease and no demonstrable immunodeficiency. These patients are predominantly nonsmoking elderly women. High-resolution computed tomography scans revealed the characteristic findings of multifocal bronchiectasis combined with multiple small nodules. NTMs are ubiquitous environmental organisms. Because exposure to these organisms is universal and the occurrence of the disease is rare, normal host defense mechanisms must be effective enough to prevent the infection.

All patients with NTM lung disease do not need to receive long-term antibiotic treatment. As the American Thoracic Society guidelines point out, one of the most difficult questions may be when to start antibiotic therapy in patients with NTM lung disease. The decision to begin treatment is made by weighing the anticipated benefits and risks. The decision is relatively easy in patients with profound symptoms and destructive lesions; however, the decision is difficult in patients with mild symptoms and non-advanced lesions. Factors that must be considered include the patients' age, whether the symptoms are mild or equivocal, and the presence of comorbidities. In all cases, close observation is necessary if treatment is not performed. However, few studies have shown that patients with certain characteristics show disease progression.

The treatment of NTM pulmonary disease depends on the infecting species, but decisions concerning the institution of treatment are never easy. Treatment requires the use of multiple drugs for 18 to 24 months. Thus, treatment is expensive, often has significant side effects, and is frequently not curative. Therefore, clinicians should be confident that there is sufficient pathology to warrant prolonged, multidrug treatment regimens. In all of the situations, outcomes can be best optimized only when clinicians, radiologists, and laboratories work cooperatively.

This study will examine why some people are more susceptible to NTM lung disease and why some people of NTM lung disease are more difficult to treat. This study will examine the patient and bacterial characteristics, course of disease and treatment of NTM infections, as well as the genetics involved in these infections.

Patients with diagnosed NTM lung disease may be eligible for this study. All participants will have a medical and family history, blood tests, imaging studies that may include X-rays, computed tomography (CT) scans, and genetic and serologic studies. The aim of this study is to identify patient and bacterial characteristics that contribute to disease susceptibility, disease progression, and treatment failure. Subjects are recruited from among patients who are diagnosed to have NTM lung disease at the Samsung Medical Center in the Republic of Korea.