Serum IL-6 levels associate with oxygen kinetics during maximal exercise
and early recovery in patients with sarcoidosis
V. Dionisopoulou¹, Á. Papamichalopoulos¹, Ir. Mavrou², Å. Stefanatou¹, P. Founta¹,
Á. Samakovli², Å. Pappa², Å. Pouliou², S. Nanas², Ch. Roussos^2
110th Pulmonary Medicine Department, "Sotiria" Chest Diseases Hospital, Athens, Greece,
²Intensive Care Unit and Pulmonary Medicine Department, University of Athens, Athens, Greece

SUMMARY: Objective: To investigate the association between interleukin-6 (IL-6), a cytokine implicated in the regulation of inflammatory responses, and oxygen kinetics during maximal CPET and early recovery in patients with sarcoidosis. Material and Methods: Twenty-six patients with sarcoidosis (11 male/15 female; mean age, 42±11 years) and 11 healthy volunteers (3 male/8 female; mean age 29±5 years) underwent maximal CPET on a treadmill. Breath by breath analysis was used for measuring oxygen uptake (VO₂), anaerobic threshold (AT) and first-degree slope at the early phase of recovery. Serum levels of IL-6 were measured prior to, at peak, and 15 minutes after the end of exercise with a highly sensitive ELISA test kit. Results: Patients with sarcoidosis had significantly higher serum IL-6 levels and lower VO₂ values at peak exercise (peak VO₂ 80±17% pred vs 90±19% pred, P<0.05), and slower recovery (1±0.289 lt/min/min vs 1.24±0.166, P=0.003) compared to healthy subjects. An inverse relationship between serum IL-6 levels and both peak VO₂ (lt/min) (r= -0.483, P=0.013) and anaerobic threshold (ml/kg/min) (r= -0.507, P=0.008) was found. The mean value of serum IL-6 levels in patients with a VO₂/t slope of <0.8 L/min/min was significantly higher than in patients with a VO₂/t slope of >=0.8 L/min/min (P <0.05). Conclusion: These findings suggest that an inflammatory process may play an important role in the pathophysiological mechanisms of exercise limitation in patients with sarcoidosis. Pneumon 2003, 16(2):163-172.
Key words: Sarcoidosis, interleukin-6, cardiopulmonary exercise testing, oxygen kinetics.
Correspondence: Vassiliki Dionisopoulou, Ergospirometry Department, Chest Diseases Division, Intensive Care Unit inEvgenidio Therapeftiriold Hospital, University of Athens, 20, Paradiamantopoulou Str. GR-11528, Athens, Tel: 210 7236743, Fax: 210 7242785, e-mail: vasodion@otenet.gr

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