ABSTRACT: BACKGROUND:Sarcoidosis is a systemic inflammatory multi-organ disease almost always affecting the lungs. The etiology remains unknown, but the hallmark of sarcoidosis is formation of non-caseating epithelioid cells granulomas in involved organs. In Scandinavia, >?30% of sarcoidosis patients have Löfgren's syndrome (LS), an acute disease onset mostly indicating a favorable prognosis. The impact of dysregulation of lipid mediators, which has been investigated in other inflammatory disorders, is still unknown. METHODS:Using three different liquid chromatography coupled to tandem mass spectrometry targeted platforms (LC-MS/MS), we quantified a broad suite of lipid mediators including eicosanoids, sphingolipids and endocannabinoids in bronchoalveolar lavage (BAL) fluid from pulmonary sarcoidosis patients (n?=?41) and healthy controls (n?=?16). RESULTS:A total of 47 lipid mediators were consistently detected in BAL fluid of patients and controls. After false discovery rate adjustment, two products of the soluble epoxide hydrolase (sEH) enzyme, 11,12-dihydroxyeicosa-5,8,14-trienoic acid (11,12-DiHETrE, p?=?4.4E-5, q?=?1.2E-3, median fold change?=?6.0) and its regioisomer 14,15-dihydroxyeicosa-5,8,11-trienoic acid (14,15-DiHETrE, p?=?3.6E-3, q?=?3.2E-2, median fold change?=?1.8) increased in patients with sarcoidosis. Additional shifts were observed in sphingolipid metabolism, with a significant increase in palmitic acid-derived sphingomyelin (SM16:0, p?=?1.3E-3, q?=?1.7E-2, median fold change?=?1.3). No associations were found between these 3 lipid mediators and LS, whereas levels of SM 16:0 and 11,12-DiHETrE associated with radiological stage (p?