These results support a role for platelet turnover, factor V, and aAPCR in the thrombosis of ET as well as the association between JAK2 V617F allele burden and either decreased free PS or increased TF and soluble markers of platelet and endothelial activation.
Our objective was to study the effect of OC on the two main determinants of the APC-resistance test, free protein S and free tissue factor pathway inhibitor (TFPI).
Laboratory assays are currently available to diagnose and type hereditary thrombophilia due to deficiency or dysfunction of one of the anticoagulant factors antithrombin (AT), protein C (PC) and protein S (PS), and APC resistance without the need of DNA analysis.
Since the presence of activated protein C (APC) resistance has been reported to interfere with PS activity assays resulting in an apparent type II PS deficiency, we retrospectively tested a pre-transplantation frozen plasma sample for APC resistance.
Our objective was to study the effect of OC on the two main determinants of the APC-resistance test, free protein S and free tissue factor pathway inhibitor (TFPI).
The diagnosis of factor V Leiden thrombophilia is established in a proband by identification of a heterozygous or homozygous c.1691G>A variant (referred to as the factor V Leiden variant in <i>F5</i>, the gene encoding factor V) in conjunction with coagulation tests such as the APC resistance assay.
Also, in comparison with patients with LDVT carrying GG genotype of FV gene 1691G>A polymorphism, the following activities reduced significantly: prothrombin time, activated partial thromboplastin time, fibrinogen, protein C, and protein S, while activated protein C resistance and lupus anticoagulant positive rate increased in patients carrying A allele (GA + AA).
The incidence of activated protein C resistance caused by the mutation of factor V Leiden was in six patients (5.9%) with adverse pregnancy outcomes, and in four patients (6.6%) from the control group.
In both the ex vivo and in vitro studies dabigatran interfered significantly with activated protein C resistance ratios observed in normal subjects and in factor V Leiden heterozygous carriers.
The associations of the following mutations in inherited thrombophilias and IVF outcomes were explored: factor V Leiden (FVL), prothrombin gene G20210A mutation (PGM), 5,10-methylentetrahydrofolate reductase (MTHFR) C677T, MTHFR (A1298C) and activated protein C resistance (APCR).
The difference of homocysteine, folate, vitamin B12, antithrombin III activity, protein C activity, free protein S activity, and activated protein C resistance were not statistically significant; and the number of subjects with MTHFR C677T, prothrombin G20210A, and factor V Leiden mutations were similar between the study groups.
High APC resistance was associated with breast cancer in both factor V Leiden non-carriers (OR 6.5, 95% CI 4.1-10.4) and carriers (OR 38.3, 95% CI 6.2-236.6).