Plasma cytokine levels as markers of pathogenesis and treatment response in patients with non-tuberculous mycobacterial pulmonary disease

We investigated the value of plasma cytokine levels as markers of pathogenesis and treatment response in patients with non-tuberculous mycobacteria (NTM) pulmonary disease. Plasma cytokine levels were measured and compared among patients with NTM pulmonary disease (n=111), tuberculosis (TB) patients (n=50), and healthy individuals (n=40). Changes during treatment were monitored at 3 and 6 months after treatment. According to the treatment response, NTM patients were classified as 'resistance' or 'sensitivity' responders. The results revealed that five out of twelve cytokines exhibited significantly higher levels in NTM patients compared to controls. Among these, interleukin (IL)-6 demonstrated the strongest discriminating capacity for NTM. Furthermore, when combined with IL-1 beta, they efficiently distinguished between NTM drug-resistant and drug-sensitive patients, as well as between NTM and TB groups. Additionally, IL-6 levels initially rose and then decreased in the NTM drugresistant group during the six months of treatment, similar to the behavior of IL-1 beta in the NTM drug-sensitive group. Subgroup analyses of the sensitive group with differential treatment responses revealed an increase in IL-10 levels in the six-month treatment responders. A high IL-6/IL-10 ratio was associated with increased disease severity of NTM and TB. Collectively, combinations of various plasma cytokines, specifically IL-1 beta, IL-6, and IL-10, effectively distinguished NTM patients with varying mycobacterial burdens, with IL-6 and IL-10 emerging as potential biomarkers for early treatment response. The combination of IL-6 and IL-1 beta demonstrated the highest discriminatory value for distinguishing between NTM-resistant and NTM-sensitive groups as well as between NTM and TB groups.