Analysis Of Clinical And Laboratory Characteristics In Thrombotic Thrombocytopenic Purpura And Screening Of Acquired/Hereditary Risk Factors In Venous And Arterial Thrombosis

Objective:To analyze the clinical features, outcome and laboratory characteristics of patients with TTP, and determine diagnostic value of ADAMTS13 activity for TTP.Method:Thirty-seven TTP patients admitted to our hospital from 1998 to 2009 were analyzed. The number of schistocytes per 5,000 red cells was counted at 1000-power magnification. The results were expressed as number of schistocytes per 100 red cells. Plasma ADAMTS13 activity was determined in 22 patients with the FRET-vWF86 assay. T lymphocyte subpopulation was measured in 18 TTP patients and 20 healthy controls with FACS Calibur.Results:There were 30 patients (81.08%) with the triad of TTP, including hemolytic anemia, thrombocytopenia and neurologic abnormalities; 7 (18.92%) had the classical pentad of TTP. Major etiologic factors were acquired autoimmune disorders (35.14%) or idiopathic TTP (56.76%). The schistocytes of peripheral blood smears were present in all cases with a mean of 4.4%and a range of 0.3%-13.4%. Only 4 idiopathic TTP patients (18.18%) had severe ADAMTS 13 deficiency (activity<10%); 9 (40.91%) had moderate deficiency of ADAMTS 13 activity (activity: 10-40%); another 9.(40.91%) had normal ADAMTS 13 activity (>4.0%). CD3+cell counts and CD4+cell counts were significantly lower in TTP patients than those in controls (P＜0.05), whereas there was no statistical difference between CD 8+T cell counts in TTP patents and that in normal controls (P>0.05). In this study, plasmapheresis in combination with plasma infusion is the main therapeutic method.21 of 26 patients (80.77%) accepting plasmapheresis achieved complete remission; those patients who only underwent plasma infusion had low remission rate (2/11; 18.18%) and high mortality (9/11; 81.82%).4 patients with packed RBC infusion manifested transient exacerbation of neurologic or psychiatric symptoms.Conclusion:The diagnosis of TTP is still based on clinical features including evidence of microangiopathic haemolysis. Plasma ADAMTS 13 activity assay is highly specific but lowly sensitive indicator in diagnosing idiopathic TTP. Cellular immune abnormality may be associated with TTP. Chapter I Acquired risk factors analysis in deep vein thrombosis patientsObjective:To analyze clinical features and acquired risk factors for Chinese patients with deep vein thrombosis.Methods:Three hundred and eighty-nine patients with deep vein thrombosis (during 2005～2009) were analyzed retrospectively.Results:In the serials,204 males and 185 females, male to female ratio was 1.1. Among the 389 cases with median age of 47 (range from 12 to 90), 253 (65.04%) presented acquired risk factors. There was not known risk factors in 136 (34.96%) cases. Major acquired risk factors were trauma/surgery (26.74%), malignancy (14.91%), pregnancy (8.23%), varix (8.23%), long-term immobilization in bed (5.40%) and autoimmune disorders (2.57%).Conclusions:The trauma/surgery, especially fracture or osteological operations, and malignancy are the main acquired risk factors of deep vein thrombosis in China. Chapter II Screening of Inherited risk factors in patients with arterial or venous thrombosisObjective:To identified the incidence of Hyperhomocysteinaemia, antithrombin activity deficiency, protein C activity deficiency, decreased total protein S concentration, prothrombin 20210A allele and FV Leiden mutation in Chinese patients with arterial or venous thrombosis.Methods:A total of 350 subjects, including 120 patients with deep vein thrombosis,130 patients with cerebral infarction and 100 healthy controls, were consecutively entered into our study. Blood was collected in tubes containing 3.8% trisodium citrate. Plasmas were prepared by centrifugation for 15 minutes at 3000rpm at room temperature and stored at -70℃in 1.5mL aliquots until the time of analysis. Antithrombin activity and protein C activity were measured with a chromogenic method using S-2772 or S-2366 as substrate respectively on automatic analyzer (HITACHI 7170A). Total protein S concentration was determined by polyclonal enzyme-linked immunosorbent assay (ELISA). Plasma homocysteine levels were determined by enzymatic cycling assay. Hyperhomocysteinaemia was defined as a value above the 95th percentile of healthy subjects. Anticoagulation factors deficiencies were defined as a value lower than the 95th percentile of healthy subjects. Genomic DNA was extracted from whole blood in each subjects using standard method. For the identification of FV Leiden and prothrombin 20210A allele genetic mutations, we used the PCR followed by restriction fragment length polymorphism analysis. Genomic DNA was specifically amplified for exon 10 of the factorV gene and 3'-UT regions of the prothrombin gene using PCR respectively. The fragments obtained by PCR were digested by Mnll or Hindlll respectively and then examined by agarose gel electrophoresis.Results:Compared with the control group, The plasma level of total protein S concentration and activities of Antithrombin and protein C were significantly lower in DVT patients (P<0.05). The plasma level of homocysteine was higher in DVT patients than that in controls (P＜0.05). The incidence of any anticoagulation factor deficiency in patients with DVT was 32.5% (39/120).7.5% of patients (9 out of 120) had Hyperhomocysteinaemia; 15% of patients (18 out of 120) had low AT activity; 13.33% of patients (16 out of 120) had a deficiency in PC; 6.67% of patients (8 out of 120) had a decreased total protein S concentration. The level of AT activity in cerebral infarction patients was not different from the controls with statistical significance (P>0.05). Both plasma level of homocysteine and the ratio of who shew hyperhomocysteinaemia were significantly higher in cerebral infarction patients than those in healthy controls (P<0.05). Thrombotic risk assessment by logistic regression analysis demonstrated that both antithrombin deficiency (OR=3.82) and protein C deficiency (OR=3.20) are strong independent risk factors for deep vein thrombosis (P<0.05). Neither plasma level of Total protein S concentration (OR=1.16) nor hyperhomocysteinaemia (OR=1.40) was significantly associated with venous thrombophilia (P>0.05). None of the subjects, including 100 healthy controls,120 DVT and 130 cerebral infarction patients, was found to have abnormal prothrombin 20210A allele or FV Leiden mutation.Conclusion:Antithrombin activity deficiency and protein C activity deficiency are strong independent risk factors of venous thrombosis in Chinese race. Both hyperhomocysteinaemia and decreased total protein S concentration are considered a relatively weak prothrombotic factors for venous thrombophilia in Chinese population. Antithrombin activity deficiency is not the independent risk fator for cerebral infarction in Chinese race. There is a strong association between hyperhomocysteinemia and cerebral infarction. Neither prothrombin 20210A allele nor FV Leiden mutation is the thrombophilic risk factor of DVT and cerebral infarction in Chinese race.