IL-6 gene expression in white blood cells was increased in the COPD III and IV group compared to the COPD I and II group (Figure 4A, p = 0.037), and IL-6 level in blood plasma was increased in the COPD I and II group compared to the NOS group (Figure 4B, p < 0.05). The gene discussed is IL6; the disease is chronic obstructive pulmonary disease.