Although IGFBP5 was significantly upregulated in only ciliated cells of COPD lungs relative to controls (p = 0.029), given a known genetic association of IGFBP5 with COPD [32] and a potential application as a serum biomarker in patients with COPD, we added IGFBP5 to this analysis. The gene discussed is IGFBP5; the disease is chronic obstructive pulmonary disease.