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.