Abstract
Background: In recent years, the incidence of Mycobacterium avium complex pulmonary disease (MAC-PD) has been increasing. Diagnosis requires identification of pathogens on multiple occasions in addition to characteristic observation of lesions on imaging examinations, identification of pathogens on bronchoscopic examination, or other pathological evidence. As a result, the diagnosis is non-definitive in many patients who produce no sputum and do not wish to undergo bronchoscopic examination. Glycopeptidolipid (GPL)-core antibody to MAC is an easy serological test. Therefore, GPL-core antibody may be useful for diagnosing MAC-PD.
Aims: This study aimed to estimate the usefulness of GPL-core antibody for diagnosing MAC-PD by investigating patients who were positive for GPL-core antibody.
Method: A total of 66 patients who were positive for GPL-core antibody were retrospectively investigated, and their characteristics were evaluated. The cut-off value for a positive finding was 0.7 U/mL.
Results: The median GPL-core antibody titer was 2.75 U/mL. Overall, 27 patients with MAC-PD met the ATS guidelines, and 11 were positive once on sputum culture. The mean antibody titer was 5.65 U/mL with identification of pathogens and 3.61 U/ml without (p=0.089). On chest computed tomography (CCT), 48 patients showed micronodular shadows and divergent shadows, and 48 showed bronchodilation. The mean antibody titer was higher in patients with than without these shadows on CCT (p=0.0014, p<0.0001).
Conclusion: GPL-core antibody titer was higher in patients with MAC-PD when shadows were seen on CCT. Therefore, GPL-core antibody is useful for diagnosing MAC-PD.
- © 2014 ERS
