RELB and chronic obstructive pulmonary disease: The objectives of this study were: (1) to assess systemic RelB mRNA expression relative to other inflammatory markers relevant to both COPD pathogenesis and whose expression is regulated by RelB (e.g. Cox-2, IL-8, IL-1β) in stable-state and exacerbating COPD patients and (2) to assess associations between these two subject groups in relation to acid-base, cardiovascular and pulmonary patient variables.