12‐hydroxy‐eicosatetraenoic acid (12‐HETE): a biomarker of Churg‐Strauss syndrome

BACKGROUND: Churg-Strauss syndrome (CSS) shares similarities with asthma and hypereosinophilic syndrome (HES). Eicosanoids--important inflammatory and signaling molecules--are present in exhaled breath condensate (EBC) and broncho-alveolar lavage fluid (BALF). OBJECTIVES: To assess eicosanoid profile both in EBC and BALF of CSS subjects searching for a pattern characteristic of this syndrome. METHODS: EBCs from 23 CSS patients, 30 asthmatics, 12 HES patients and 54 healthy controls (HC) were assessed quantitatively for 19 eicosanoids by a high-performance liquid chromatography - tandem mass spectrometry (HPLC-MS/MS). In addition, in 21 of 23 CSS subjects and in nine asthmatics, eicosanoids were determined in BALF. RESULTS: EBC from CSS patients showed markedly elevated levels of 12-HETE as compared with other studied groups. BALF was characterized by a significant elevation of 12-HETE and its metabolite 12-tetranor HETE in CSS as compared with asthma. Clinical activity of CSS correlated with 12-HETE and its metabolites levels in BALF, but not in EBC. CONCLUSION AND CLINICAL RELEVANCE: CSS is clearly distinguished from bronchial asthma, and HES by a marked increase in 12-HETE concentration in both EBC and BALF. This points to a possible new pathogenic mechanism in CSS and may help in future in establishing the diagnosis of CSS.