TFRC and chronic obstructive pulmonary disease: To determine wether the increased iron accumulation in COPD alveolar macrophages was a result of an increase in the expression of mRNAs encoding iron uptake proteins, we assessed the expression of transferrin and the transferrin receptor by real-time RT-PCR using RNA from 8 non-COPD lungsamples and 16 GOLD 4 COPD lungsamples.