RPS4Y1 and chronic obstructive pulmonary disease: As for the COPD smokers and non-smokers, the majority of these genes are elevated compared to non-smoking controls with the exception of RPL10L (ribosomal protein), RPS4Y1 (ribosomal protein), EIF1AY (translation initiation factor), (transcription factor), (histone binding protein) and DDX3Y (involved in transcription) being down-regulated in COPD compared to healthy non-smokers.