Vol. 7, Issue 1, Part A (2025)

Background: Symptomatic disease due to Mycobacterium avium intracellulare complex (MAI) infection is known to occur commonly in the presence of structural lung diseases such as cystic fibrosis(CF), bronchiectasis (BE), and chronic obstructive pulmonary disease(COPD), but is not described in association with asthma.

We hypothesized an association between pulmonary MAI infection and brachial asthma and evaluated the possible mechanism which might explain the association of the two diseases.

Methods: This was a retrospective study and all difficult to treat asthma patients that were admitted to the department of pulmonary medicine at the teaching hospital of the University. There were 139 patients with difficult-to-control asthma and 48 of them have found pulmonary MAI infection.

Results: The most common symptoms were worsening cough (80%), sputum production (53%), frequent exacerbations (38%), and hemoptysis (31%).

MAI infection subjects were older (60.2±7.9 vs 41.9±12 years; P<0.001) and had more severe airflow obstruction (FEV1, 53% [39%-75%] vs 80.5% [74% -96%]; P<0.001). Peripheral blood eosinophilia was higher compared to patients without MAI infection (8.4±4.8% vs 5.9±3.4; P<0.001) and total IgE level also was higher in MAI infection subjects (200.6±80.4 I/V vs 100.9±76.5 I/V; P <0.002).

There was no difference between MAI infection subjects and control subjects in the proportions using inhaled corticosteroids (all patients with difficult to control asthma received ICS) and there was also no difference in the average daily dose of ICS at the time of presentation. However, MAI infection group had used ICS for a longer period (15 [5.9 -18.0] vs 5 [1.75 -8.0] years; P = 0.001). The use of oral or IV corticosteroids for frequent exacerbation was urged in MAI infection group (P<0.001).

Of the 48 patients, 26 were treated with antibiotics for MAI pulmonary infection, 21 demonstrating clinical improvement or resolution of these presenting symptoms.

Conclusion: MAI pulmonary infection can be associated with brachial asthma, especially in patients with higher levels of biomarkers of Th2 type inflammation, and should be considered in difficult to treat disease.

More severe chest symptoms, including hemoptysis, older age patients, more severe airflow limitation with greater exposure of inhaled and systemic corticosteroids are indicated to the presence of MAI pulmonary infection in difficult to treat asthma.