The incidence of nontuberculous mycobacterial lung disease (NTM-LD) is increasing worldwide and in Eastern Asia. NTM-LD leads significant morbidity and mortality, around 25% within 5 years, but the treatment rate is low because the course of NTM-LD is indolent, especially in nodular-bronchiectatic (NB) form. However, there is no biomarker proven for predicting the progression in NB form of NTM-LD. Recently, it has been reported that the ratio of membrane-form programmed death-1 (PD-1) expressed T cells increased in patients with NTM-LD and it was associated with disease severity and progression. The mechanism has been speculated as a "immune exhaustion". In contrast to PD-1 expressed in cell membrane, soluble-form PD-1 is another biomarker that can be easily detected in serum. We recently reported that soluble PD-1 significantly correlated with cavitary lesion and disease progression in patients with NB-form NTM-LD in Taiwan. However, this has not been validated in other countries and ethnicities. Furthermore, the usefulness of soluble PD-1 in diagnosis and predicting mortality warrants further studies.
Age ≥ 20 years
NTM-LD: (N=250) Diagnosis is made on the basis of the guidelines produced by the American Thoracic Society.Patients have pulmonary symptoms with identified chest image and fit with the microbiology criteria.
NTM pulmonary colonizers and others: (N=100) Those without fulfilling the diagnostic criteria but having at least one set of positive sputum for MAC or patients infected with NTM other than MAC species.
Pulmonary tuberculosis (TB): (N=100) Those with respiratory specimen culture positive for Mycobacterium tuberculosis or typical TB pulmonary pathology.
Patients who have acquired immunodeficiency syndrome