Patients with non-tuberculous mycobacterial lung disease have elevated transforming growth factor-beta following ex vivo stimulation of blood with live Mycobacterium intracellulare

We previously found that a subset of patients with pulmonary non-tuberculous mycobacterial (pNTM) disease were taller, leaner, and had a higher prevalence of pectus excavatum and scoliosis than uninfected controls. Additionally, whole blood of pNTM patients stimulated ex vivo with live Mycobacterium intracellulare produced significantly less interferon-gamma (IFN gamma) compared to that of uninfected controls. Since IFN. production can be suppressed by transforming growth factor-beta (TGF beta), an immunosuppressive cytokine, we measured basal and M. intracellulare-stimulated blood levels of TGF beta in a group of 20 pNTM patients and 20 uninfected controls. In contrast to the IFN. findings, we found that stimulated blood from pNTM patients produced significantly higher levels of TGF beta compared to controls. Since pNTM patients frequently possess body features that overlap with Marfan syndrome (MFS), and increased TGF beta expression is important in the pathogenesis of MFS, we posit that a yet-to-be-identified syndrome related to MFS predisposes certain individuals to develop pNTM disease.