IL7R and chronic obstructive pulmonary disease: Next, exploiting the ability of the centrality plot to identify important nodes/variables that determine disease severity, as well as the nature of their influence, we identified SO2, PM10, PM2.5, O3, and lnc-IL7R tetrad as an important predictor of disease progression and severity, and that while SO2, PM10, and PM2.5, drove disease progression and were positively correlated with COPD-E severity, O3 and lnc-IL7R attenuated progression and were negatively associated with disease severity (Figure 3C).