For this study, four recombinant antigens, the newly identified MAC proteins, MAV2054 and MAV5183, and the well-characterized proteins HspX and 38-kDa, were prepared. MAV5183 were significantly higher in MAC-PD than in pulmonary TB subjects. In addition, the levels of IgG against all antigens in the and fibrocavitary forms were higher than those in the and nodular bronchiectatic forms, respectively. Based on sensitivity and receiver operator characteristic curve analysis, the best candidates for detection of MAC-PD and pulmonary TB were MAV2054 and the 38-kDa antigen, respectively. In total, 76.0% of MAC-PD and 65.0% of active TB patients were reactive to at least two antigens. In contrast, only 2.8% of HC subjects were reactive with two or more antigens. Our findings suggest that an enzyme-linked immunosorbent assay (ELISA) using the four antigens would be valuable for screening for mycobacterial lung disease, including MAC-PD and pulmonary TB, although it does not provide good discrimination of the disease-causing pathogens. INTRODUCTION More than 100 species are recognized in the genus and complex (MAC), (4). NTM can cause chronic pulmonary disease (PD) in humans similar to slowly progressive pulmonary tuberculosis (TB), but unlike tuberculosis, contamination by NTM is not transmitted from person to person. Currently, the diagnosis of NTM-PD Teijin compound 1 remains a challenge due to the complex diagnostic criteria, and the management of NTM-PD is usually difficult due to the prolonged treatment duration and resistance to antimycobacterial drugs (5). MAC is the most common cause of NTM lung diseases and is an opportunistic infectious agent encountered frequently in patients who are immunocompromised, such as individuals with human immunodeficiency virus (HIV) contamination (6). Furthermore, the prevalence of MAC-PD in immunocompetent patients has increased recently (5). The diagnosis of MAC-PD is usually complicated and time-consuming, because MAC may colonize the respiratory tract, and the isolation of MAC from sputum specimens often has no clinical or microbiologic significance due to its ubiquity in nature. In addition, discrimination of MAC-PD from pulmonary TB is usually difficult. Although the American Thoracic Society (ATS) has outlined guidelines for the diagnosis of NTM, the diagnosis of MAC-PD requires combined clinical, radiographic, and microbiologic evidence (5). Therefore, there have been many efforts to overcome these difficulties in diagnosis of MAC-PD. There have been few attempts to develop a serologic test for diagnosis of MAC-PD and to distinguish it from other lung diseases, such as TB (7). Serodiagnostic assessments using multiple mycobacterial antigens (Ag) are attractive for diagnosis of the disease due to their simplicity and economics. Use of glycopeptidolipids (GPLs) as markers for differentiation of MAC-PD from pulmonary TB and other mycobacterial infections has been reported (8C11). However, mycobacterial glycolipids, such as GPL and cord factor, are difficult to purify in quantity, and their preparation requires great labor and is associated with a high cost. KatG is the only Rabbit Polyclonal to PCNA protein reported as a novel diagnostic marker of contamination (12). Therefore, identification of seroreactive proteins from MAC culture filtrate and evaluation of their usefulness to distinguish MAC-PD from pulmonary TB or healthy controls (HC) still need to be investigated more extensively. We previously reported the serodiagnostic potential of a mycobacterial antigen cocktail for detection of TB using an enzyme-linked immunosorbent assay (ELISA) (13). In the present study, to apply the combined ELISA for serologic diagnosis of MAC-PD, we identified two candidates, MAV2054 and MAV5183, by screening using multidimensional fractionation of culture filtrate proteins (CFP) and probing with sera from patients with MAC-PD. In addition, HspX and 38-kDa protein (PstS1), well-known serodiagnostic antigens, were included in the antibody detection assay. The serodiagnostic potential of all four antigens was evaluated in subjects with MAC-PD, pulmonary TB, or latent TB and in HC. MAV2054 Teijin compound 1 and MAV5183 proteins elicited significantly higher antibody responses in MAC-PD than in pulmonary TB and HC subjects. MATERIALS AND METHODS Subjects. Sera were obtained from 175 patients with MAC-PD (median age = 60 years; age range = 27 to 85 years; percentage of males, 38%), 123 with active pulmonary TB (median age = 52 years; age range = 18 to 91 years; Teijin compound 1 percentage of males, 63%), 151 with latent TB contamination (LTBI) as defined by positive tuberculin skin test (TST) results (median age = 22 years; age range = 14 to 63 years; percentage of males, 54%), and 141 HC as defined by unfavorable TST results (median age = 23 years; age range = 8 to 69 years; percentage of males, 62%). A total of 175 MAC patients who satisfied the diagnostic criteria of the American Thoracic Society (ATS) (5) were prospectively enrolled at the Asan Medical Center (Seoul, South Korea) or Samsung Medical Center (Seoul, South Korea). All.
