IL6 and chronic obstructive pulmonary disease: Conversely, our quantitative RT-PCR results showed that IL-6 responded only in a dose-dependent manner for 6 hours and in a time-dependent manner at low dose (Figure 2C), while our in silico analysis showed that IL-6 had no significant association with COPD (Figure 5D, P = 0.3742) (GSE5060, n = 38).