Innate and adaptive immune responses in subjects with CPA secondary to post-pulmonary tuberculosis lung abnormalities.

Background: Post-tuberculosis lung abnormality (PTLA) is the most common risk factor for chronic pulmonary aspergillosis (CPA), and 14%-25% of the subjects with PTLA develop CPA. The pathogenesis and the host immune response in subjects with PTLA who develop CPA need to be better understood.

Methods: We prospectively compared the innate and adaptive immune responses mounted by patients of PTLA with or without CPA (controls). We studied the neutrophil oxidative burst (by dihydrorhodamine 123 test), classic (serum C3 and C4 levels) and alternative (mannose-binding lectin [MBL] protein levels) complement pathway, serum immunoglobulins (IgG, IgM and IgA), B and T lymphocytes and their subsets in subjects with PTLA with or without CPA.

Results: We included 111 subjects (58 CPA and 53 controls) in the current study. The mean ± SD age of the study population was 42.6 ± 15.7 years. The cases and controls were matched for age, gender distribution and body weight. Subjects with CPA had impaired neutrophil oxidative burst, lower memory T lymphocytes and impaired Th-1 immune response (lower Th-1 lymphocytes) than controls. We found no significant difference between the two groups in the serum complement levels, MBL levels, B-cell subsets and other T lymphocyte subsets.

Conclusion: Subjects with CPA secondary to PTLA have impaired neutrophil oxidative burst and a lower Th-1 response than controls.