RBP4 and chronic obstructive pulmonary disease: We found that RBP4 transcripts were significantly down-regulated in the PA-COPD lungs in comparison to con-COPD lungs; in anti–IL-17A–treated lungs, there was a significant induction of RBP4 transcription, whereas in rm–IL-17A–treated lungs, there was a significant reduction of RBP4 transcription (Figure 6B).