ORIGINAL ARTICLE Circulating endothelial microparticles in children with Henoch–Scho ¨nlein purpura; preliminary results Ismail Dursun • Ruhan Du ¨su ¨ nsel • Hakan M. Poyrazoglu • Zubeyde Gunduz • Turkan Patıroglu • Harun U ¨ lger • Metin Kaya Gurgoze Received: 14 January 2010 / Accepted: 5 May 2010 / Published online: 25 May 2010 Ó Springer-Verlag 2010 Abstract The aim of this study was to investigate the levels of circulating endothelial microparticles (EMPs) in children with HSP and to determine whether there was a difference between patients with nephritis and those with- out nephritis. Twenty patients with HSP aged between 2.5 and 15 and 10 age-and sex-matched healthy controls were enrolled in the study. The HSP group was divided into two groups, including patients with nephritis (n = 9) and those without nephritis (n = 11). In all groups, circulating EMPs were enumerated by flow cytometry, after staining platelet- free plasma with PE-conjugated anti-CD144. At the same time, human umbilical vein endothelial cells (HUVEC) were incubated with the platelet-free plasma of patients with HSP and that of the control group. Then, circulating EMPs were counted in HUVEC supernatant incubated with the platelet-free plasma of patients and control groups, after staining the supernatant with PE-conjugated anti-CD146. Circulating EMPs were significantly higher in both the active and the remission period of the patient groups com- pared with the control subjects. In the patient group, there were no statistically significant differences in the level of circulating EMPs between patients with nephritis and those without nephritis. Both CD144 and 146?EMP in patients with HSP nephritis in the active period were substantially higher than in those remissions. CD144?EMP in the active period were substantially higher than in the remission per- iod in patients without nephritis. We detected that circu- lating EMPs increased in patients with HSP in both active and remission periods. Although clinical and laboratory findings return to normal in the remission period, the increased circulating EMPs may show that the subclinical inflammatory process is continuous. We think that circu- lating EMPs could be used as a surrogate marker for sub- clinical inflammation in HSP. Keywords Henoch–Scho ¨nlein purpura Á Endothelial dysfunction Á Endothelial microparticles Abbreviations HSP Henoch–Scho ¨nleın purpura EMP Endothelial microparticle VE Vascular endothelial PFP Platelet-free plasma I. Dursun Á R. Du ¨su ¨nsel Á H. M. Poyrazoglu Á Z. Gunduz Á M. K. Gurgoze Faculty of Medicine, Department of Pediatric Nephrology, Erciyes University, Kayseri, Turkey e-mail: druhan@erciyes.edu.tr H. M. Poyrazoglu e-mail: drpoyrazoglu@yahoo.com Z. Gunduz e-mail: zgunduz@erciyes.edu.tr M. K. Gurgoze e-mail: mkgurgoze@yahoo.com T. Patıroglu Faculty of Medicine, Department of Pediatric Immunology, Erciyes University, Kayseri, Turkey e-mail: turkanp@erciyes.edu.tr H. U ¨ lger Faculty of Medicine, Department of Anatomy and Research Institute, Erciyes University, Kayseri, Turkey e-mail: ulger@erciyes.edu.tr I. Dursun (&) Division of Pediatric Nephrology and Rheumatology, Department of Pediatrics, 38100 Talas, Kayseri, Turkey e-mail: drdursun@hotmail.com 123 Rheumatol Int (2011) 31:1595–1600 DOI 10.1007/s00296-010-1528-9