Exhaled 8-isoprostane as a prognostic marker in sarcoidosis. A short term follow-up

BACKGROUND: 8-Isoprostane (8-IP) is a marker of lipid peroxidation. Elevated concentrations have been reported in BAL fluid and exhaled breath condensate (EBC) in sarcoidosis (S). To validate the prognostic value of this marker we tested whether: 1. high initial EBC 8-IP predispose to more severe disease; 2. low initial concentrations increase a chance of early remission; 3. remissions are connected with the decrease of EBC 8-IP. METHODS: 40 patients (S) have been examined initially (V1) and after 8.5 ± 0.5 months (V2). EBC 8-IP concentrations were measured by ELISA. Chest X-ray, lung function test, serum ACE and Ca(2+ )concentrations, 24 hrs Ca(2+)loss, abdominal ultrasonography, symptoms evaluation were performed. RESULTS: We confirmed higher concentrations of 8-IP in EBC of patients with sarcoidosis (p = 0.001). Relative risk (RR) of persistence of disease at V2 when initial 8-IP was above 20 pg/mL was 1.04, and the frequency distributions estimated by χ(2 )test were not significantly different. A chance (RR) of early complete remission when V1 8-IP was below DL, was 3.33 (p = 0.04 by χ(2 )test). A significant decrease of 8-IP at V2 was observed only in patients who received treatment (p = 0.03), but not in those with spontaneous remission. CONCLUSIONS: We come to the conclusion, that low initial 8-IP may be a positive prognostic factor. A decrease of 8-IP in treated patients reflects a non-specific effect of treatment and is not related to mere regression of disease.