Impact of Aspergillus precipitating antibody test results on clinical outcomes of patients with Mycobacterium avium complex lung disease.

Background And Objective: Chronic pulmonary aspergillosis (CPA) is associated with mortality in patients with Mycobacterium avium complex lung disease (MAC-LD). However, the clinical significance of the positivity of Aspergillus precipitating antibody (APAb), a serodiagnostic test for pulmonary aspergillosis (PA), at the time of MAC-LD diagnosis is unknown. The objective of this study was to investigate the effects of APAb test results on the clinical outcomes of patients with MAC-LD.

Methods: We retrospectively analyzed patients who were newly diagnosed as having MAC-LD between 2007 and 2014 in our hospital and checked for APAb at the time of diagnosis.

Results: We enrolled 131 patients in this study. Of these patients, 20 (15.3%) tested positive for APAb at the diagnosis of MAC-LD. The APAb-positive patients were more frequently male (70.0% vs. 37.8%, P = 0.013) and more frequently had pulmonary emphysema (60.0% vs. 13.5%, P < 0.001) and interstitial pneumonia (15.0% vs. 1.8%, P = 0.025) compared with the APAb-negative patients. During a median follow-up period of 4.0 years, PA developed in 12 of the APAb-positive patients (60.0%, CPA: 9 and allergic bronchopulmonary aspergillosis: 3) and 12 APAb-negative patients (10.8%, CPA: 12) (P < 0.001). The APAb-positive patients had a significantly higher rate of mortality than did the APAb-negative patients (P = 0.004). A multivariate analysis indicated that older age, lower albumin, fibrocavitary or fibrocavitary and nodular/bronchiectatic radiographic features, and APAb positivity were negative prognostic factors.

Conclusions: APAb-positive patients with MAC-LD more frequently develop PA and may have an unfavorable prognosis.