['Inflammation plays a key role in atherosclerotic disease. Up until now only limited evidence exists on the mechanism of cardiovascular complications in patients with depression. In addition depression was also linked to an increase in cardiovascular mortality. The present study was designed to evaluate the extent of platelet activation and platelet-derived markers of atherosclerotic disease in patients with newly diagnosed depression.', 'This study used whole blood aggregometry, flow cytometry and ELISA to investigate platelet CD62P (P-selectin) expression and atherosclerotic markers (CD40, CD40L) as well as serum platelet factor 4 (PF-4) and beta-thromboglobulin (β-TG) levels in 46 participants. Patients with newly diagnosed, but not yet medically treated depression (n\xa0=\xa021) were compared to healthy control patients.', 'The platelet activation marker CD62P was significantly higher in patients with depression (2.62% depression versus 1.27% controls; p\xa0=\xa00.006). Further we found basal CD40 (6.7% vs. 4.8%; p\xa0=\xa00.002) and basal CD40L (31.0% vs. 22.0%; p\xa0=\xa00.025) to be elevated in patients with depression as compared to control persons. In addition sCD40L (52.7 vs. 44.4\xa0ng/ml; p\xa0=\xa00.023) and β-TG differed significantly in depressed patients (206.9 vs. 182.8\xa0ng/ml; p\xa0=\xa00.001). However, basal CD41 (97.0% vs. 96.3%; p\xa0=\xa00.57), CD42b (96.7% vs. 94.7%; p\xa0=\xa00.28) and PF-4 (89.61 vs. 81.75\xa0IU/ml; p\xa0=\xa00.10) and the aggregometry results did not differ significantly between the study groups.'] Is newly diagnosed depression associated with increased beta-thromboglobulin levels and increased expression of platelet activation markers and platelet derived CD40-CD40L?