Breath pentane excretion as a marker of disease activity in rheumatoid arthritis.

Activated inflammatory cells are capable of stimulating lipid peroxidation. In 27 patients with rheumatoid arthritis, we measured the pulmonary excretion of pentane, a product released during lipid peroxidation. We found highly significant correlations between pentane excretion and both joint inflammation (r = 0.88, p less than 0.001) and the erythrocyte sedimentation rate (r = 0.80, p less than 0.001). Patients treated with gold compounds or D-penicillamine excreted diminished amounts of pentane. The data suggest that lipid peroxidation may be related in part to the mechanism of injury in rheumatoid arthritis.