title: Circulating midkine in children with Henoch-Schönlein purpura: Clinical implications.
abstract: BACKGROUND
  Midkine (MK) is a heparin-binding growth factor, which behaves like a cytokine, involved in various cellular processes such as cellular proliferation, differentiation, survival, adhesion, and migration. Studies provided evidence for a role of MK in acute and chronic inflammatory processes. The association between midkine and Henoch-Schönlein purpura (HSP) has not yet been explored. The aim of our study was to investigate the potential role of midkine in children with HSP.
  
  
  METHODS
  A total of 152 cases consisting of 92 children with HSP and 60 age- and sex-matched healthy control children were enrolled in this prospective study. Circulating midkine, IL-2, IL-4, IL-6, IL-10, TNF, IFN-γ, and IL-17A was measured in all of the 92 patients and 60 healthy controls. Midkine diagnostic value was evaluated by receiver operating characteristic (ROC) analysis.
  
  
  RESULTS
  Renal involvement occurred in 36 of the 92 patients. Circulating midkine level was elevated in children with HSPN than those of patients without renal involvement and of the controls (326.58 (266.58-459.25) pg/ml versus 280.72 (233.67-384.36) pg/ml and 217.3 (198.98-243.65) pg/ml, respectively; P<0.05). Midkine positively correlated with IL-4, IL-6, IL17A, IgA and IgE. The threshold MK concentration of HSPN was 295.58pg/ml, with the sensitivity and specificity of 80.6% and 88.3%, respectively. The area under the receiver operating characteristic (ROC) curve (AUCROC) of MK was 0.902.
  
  
  CONCLUSIONS
  MK seems to be involved in the development of HSP. Measurement of serum levels of MK is helpful in confirming the diagnosis of HSP and predicting HSPN.
authors: Pediatric Research Institute, Qilu Children's Hospital of Shandong University, Ji'nan 250022, China; Department of Pediatric, Shandong Police Hospital, Ji'nan 250002, China.
authors: Zhantao
authors: Z
authors: Su
authors: Pediatric Research Institute, Qilu Children's Hospital of Shandong University, Ji'nan 250022, China.
authors: Xin
authors: X
authors: Lv
authors: Pediatric Research Institute, Qilu Children's Hospital of Shandong University, Ji'nan 250022, China.
authors: Yi
authors: Y
authors: Liu
authors: Pediatric Research Institute, Qilu Children's Hospital of Shandong University, Ji'nan 250022, China.
authors: Jinhang
authors: J
authors: Zhang
authors: Pediatric Research Institute, Qilu Children's Hospital of Shandong University, Ji'nan 250022, China.
authors: Jingyun
authors: J
authors: Guan
authors: Pediatric Research Institute, Qilu Children's Hospital of Shandong University, Ji'nan 250022, China. Electronic address: gaizhongtao@sina.com.
authors: Zhongtao
authors: Z
authors: Gai
mesh_terms: D000293:Adolescent; D015415:Biomarkers / Q000097:blood*; D016022:Case-Control Studies; D002648:Child; D002675:Child, Preschool; D016207:Cytokines / Q000097:blood*; D005260:Female; D006801:Humans; D011695:IgA Vasculitis / Q000150:complications / Q000175:diagnosis*; D007223:Infant; D007668:Kidney / Q000276:immunology* / Q000473:pathology; D008297:Male; D000078792:Midkine; D009393:Nephritis / Q000175:diagnosis* / Q000209:etiology; D011237:Predictive Value of Tests; D011379:Prognosis; D011446:Prospective Studies; D012680:Sensitivity and Specificity
chemical_list: D015415:Biomarkers; D016207:Cytokines; D000078792:Midkine
keywords: Biomarker; Henoch–Schönlein purpura; Henoch–Schönlein purpura nephritis; Midkine