[CHANGES IN MAC ANTIBODY LEVELS BEFORE AND AFTER SURGERY AND AT THE TIME OF RELAPSE/RECURRENCE IN MAC LUNG DISEASE--Can MAC Antibodies Be an Indicator of Postoperative Relapse/Recurrence?].

Background: Patients receiving surgical treatment for Mycobacterium avium complex (MAC), lung disease should be followed up with careful attention paid to relapse/recurrence, but there is some debate regarding the findings based on which relapse/recurrence should be diagnosed.

Purpose and methods: We hypothesized that we might be able to use anti-GPL core IgA antibodies (MAC antibodies), which have been attracting attention as a factor that may support diagnosis of MAC lung disease, to diagnose postoperative relapse/recurrence. Therefore, we compared the levels of these antibodies before and at the time of relapse/recurrence, and also compared antibody titers before and after surgery.

Result: MAC antibody titers were elevated by an average of about 50% at the time of relapse/recurrence compared to those before relapse/recurrence for 6 patients. In contrast, MAC antibody titers were about 30% lower after surgery compared to those before surgery for 37 patients.

Conclusion: It may be possible to use MAC antibodies as an indicator of postoperative relapse/recurrence for MAC lung disease.