title: [Study on activated protein C resistance and disordered coagulation in patients with myeloproliferative neoplasms].
abstract: OBJECTIVE
  To study the correlation of activated protein C (APC) resistance, coagulation factors and inhibitors abnormality and JAK2V617F mutation burden in patients with myeloproliferative neoplasms (MPN).
  
  
  METHODS
  The APC resistance was defined as the ratio of activated partial thromboplastin time (APTT) in the presence and absence of APC, i.e. APC sensitivity ratio (APCsr). Plasma protein C (PC), protein S (PS), prothrombin (FII), factor V (FV), factor VIII levels and CD11b expression on neutrophils were measured. The percentage of mutated JAK2V617F allele (V617F%) was evaluated by real time polymerase chain reaction (qRT-PCR).
  
  
  RESULTS
  Expression of CD11b on neutrophils was significantly elevated in MPN patients compared with that of the control group. APCsr, PS and FV levels were reduced in patients with MPN. The APCsr level was decreased mainly in patients with thrombosis and JAK2V617F mutant burden higher than 75%. APCsr was not only positively correlated with PS levels but also inversely correlated with JAK2V617F allele burden in JAK2V617F mutant gene carriers.
  
  
  CONCLUSIONS
  The neutrophil was activated and PS, FV level were reduced in MPN patients. The APCsr level was decreased and the occurrence of relatively acquired APC resistance was found in MPN patients with thrombosis. The APCsr is correlated with the PS level and JAK2V617F mutational furden.
authors.affiliation: State Key Laboratory of Experimental Hematology, Institute of Hematology & Blood Diseases Hospital, CAMS & PUMC, 288 Nanjing Road, Tianjin 300020, China.
authors.forename: Jie
authors.initials: J
authors.lastname: Bai
authors.forename: Yang-ping
authors.initials: YP
authors.lastname: Xue
authors.forename: Xian-hui
authors.initials: XH
authors.lastname: Xu
authors.forename: Lei
authors.initials: L
authors.lastname: Zhang
authors.forename: Meng-su
authors.initials: MS
authors.lastname: Tian
authors.forename: Lin
authors.initials: L
authors.lastname: Shen
authors.forename: Hong-yun
authors.initials: HY
authors.lastname: Zhang
authors.forename: Ren-chi
authors.initials: RC
authors.lastname: Yang
mesh_terms: D020016:Activated Protein C Resistance / Q000378:metabolism*; D000293:Adolescent; D000328:Adult; D000368:Aged; D001777:Blood Coagulation; D001778:Blood Coagulation Disorders; D005165:Factor V / Q000378:metabolism; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009196:Myeloproliferative Disorders / Q000097:blood* / Q000378:metabolism*; D017293:Protein S / Q000378:metabolism; D055815:Young Adult
chemical_list: D017293:Protein S; D005165:Factor V