Osimertinib, a third-generation epidermal growth factor receptor tyrosine kinase inhibitor (EGFR-TKI), is routinely prescribed as first-line therapy for advanced non-small cell lung cancer, regardless of the presence of the T790M resistance mutation. This study reports a rare case of Factor V inhibitor detection during osimertinib therapy in a patient with lung adenocarcinoma. These findings underscore the importance of vigilant monitoring for coagulation abnormalities during EGFR-TKI therapy.

Rare coagulation disorders pose significant diagnostic challenges emphasizing the importance of clinical vigilance and meticulous hemostatic workup for accurate diagnosis and timely management. We present two cases of exceptionally uncommon coagulopathies - isolated factor V deficiency (F5D) and combined factor V and VIII deficiency (F5F8D). Case 1 features a 24-year-old woman incidentally diagnosed with severe F5D during routine preoperative evaluation for an ovarian cyst. Despite the absence of any reported bleeding manifestations, a timely and accurate diagnosis was rendered. Perioperative management with fresh frozen plasma and postoperative monitoring ensured favorable surgical outcomes. Case 2 features a 10-year-old male presenting with prolonged gum bleeding. Following systematic hemostatic workup, a diagnosis of F5F8D was rendered, thereby guiding optimal therapeutic interventions. We herein aim to contribute valuable insights into the understanding of coagulation physiology and the diagnostic intricacies and management strategies of rare coagulation disorders.

The aim of this study is to characterize zebrafish coagulation cofactors fviii and fv mutant fish and assess if they phenocopy classical hemophilia A and factor V deficiency in humans. The embryos from fviii and fv zebrafish heterozygote mutants generated by ENU mutagenesis were purchased from the ZIRC repository. They were reared to adulthood and genotyped. The heterozygote male and female were crossed to get homozygote, heterozygote, and wild-type fish. Functional kinetic coagulation assays and bleeding assays were performed on normal and mutant adult fish, and venous laser injury assays were performed on the larvae. The DNA from fviii and fv mutants were sequenced to confirm if they have a premature stop codon in exon 19, and in exon 2, respectively, and in both mutants, the amino acid glutamine is replaced with a stop codon. Homozygous and heterozygous 5 days post fertilization (dpf) larvae for fviii and fv deficient mutants exhibited prolonged time to occlusion after venous laser injury compared to wild-type controls. The homozygous and heterozygous fviii adult mutants showed modest bleeding and delayed fibrin formation in the kinetic partial thromboplastin time (kPTT) assay with their plasma. fv homozygous larvae had poor survival beyond 12 dpf. However, heterozygous fv mutants exhibited heavy bleeding and prolonged fibrin formation in the kPTT and kPT assay compared with wild-type siblings. Our characterization showed fviii and fv mutants from ZIRC phenocopied to a considerable extent classical hemophilia A and factor V deficiency in humans, respectively. These models should be useful in studying and developing novel drugs that reverse the phenotype and in generating suppressor mutations to identify novel factors that compensate for these deficiencies.

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BACKGROUND: Coagulation factor V deficiency is rare, and perioperative management of patients with this condition is particularly important, especially during major abdominal surgery. We present a case of a patient with pancreatic duct stones combined with coagulation factor V deficiency. We share our perioperative management experience.
METHODS: A 31-year-old man presented with recurrent upper abdominal pain for 2 years.
METHODS: The diagnosis of pancreatic duct stones in the patient has been established through abdominal computed tomography and magnetic resonance imaging examinations. The diagnosis of factor V deficiency was initially identified through coagulation function tests, revealing significant prolongation of both aPTT and PT. Subsequent testing of coagulation factors and inhibitors demonstrated that the patient has a deficiency in coagulation factor V. Finally, genetic testing revealed that the factor V deficiency in this case is hereditary.
METHODS: The patient underwent a partial resection of the pancreatic head, and FFP was infused 1 hour before surgery. 600 mL of FFP was instilled 1 hour before the start of surgery along with 10 U of cryoprecipitate. and 600 ml of FFP were added during surgery. Postoperative treatment included intermittent FFP supplemental infusion in the first 5 days after surgery while monitoring the coagulation function.
RESULTS: The patient underwent a successful surgery without any abnormal bleeding or oozing during the procedure. The postoperative recovery was smooth, with no abnormal bleeding.
CONCLUSIONS: Patients with a deficiency of coagulation factor V are not contraindicated for surgery. Appropriate Fresh Frozen Plasma (FFP) replacement therapy can ensure the safe conduct of the surgical procedure. For patients with abnormal blood coagulation function, we recommend testing for coagulation factors and inhibitors, as well as performing genetic testing for abnormal coagulation factors, which can provide guidance on marriage and childbirth.

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Growing evidence supports the importance of factor (F) XI activation for thrombosis and hemostasis as well as inflammation and complement systems. In this study, we evaluated the effect of activated FXI (FXIa) on the detection of factor deficiencies by global hemostasis assays of thrombin generation (TG), plasmin generation (PG), and clot formation and lysis (CFL).
An absorbance and fluorescence microplate assay was used to simultaneously observe TG, PG, and CFL in FV-, FVII-, FVIII-, and FIX-deficient plasmas supplemented with purified factors. Coagulation was initiated with tissue factor with or without FXIa in the presence of tissue plasminogen activator. Thrombin and plasmin peak heights (TPH and PPH), maximal clot density (MCD), times to clotting (CT), thrombin and plasmin peaks (TPT and PPT) and clot lysis (LyT) and a new parameter, clot lifetime (LiT), were evaluated.
TG/CFL were elevated by the FXIa at low FV (below 0.1 IU/mL), and at FVIII and FIX above 0.01 IU/mL. FXIa affected PG only at low FV and FVII. At high factor concentrations, FXIa reduced MCD. Thrombin and plasmin substrates had effect on CT, LyT, LiT and MCD parameters.
FXIa reveals new relationships between TG, PG and CFL parameters in factor deficiencies suggesting potential benefits for discrimination of bleeding phenotypes.

BACKGROUND: Hemophilia is an X-linked, recessive inherited disease caused by a defect or deficiency of one of the coagulation factors (VIII or IX). It is considered a rare disease in females. One of the reasons that hemophilia affects females is Turner syndrome. Hemophilia with Turner syndrome is a very rare case, but the combination of Turner syndrome, hemophilia, and factor V deficiency is an isolated case that has never been recorded in the medical literature.
METHODS: In our case, a 5-year-old Syrian girl presented with hemorrhage of gum, epistaxis, and short stature. The lab tests showed: prolonged activated partial thromboplastin time and prothrombin time with deficiency of factor V (1%) and factor VIII (1%). We diagnosed hemophilia A with factor V deficiency. In addition to short stature, the patient was noted to have spaced nipples and winged neck. We performed karyotyping that showed deletion of one X chromosome (45X0), Turner syndrome. There is no family history of hemophilia or any other genetic disease.
CONCLUSIONS: In females affected with hemophilia, karyotyping should be performed. It is very important not to exclude the possibility of a combination of deficiency of more than one clotting factor, and to note that deficiency of more than one factor does not necessarily increase the severity of bleeding compared with deficiency of a single factor.

BACKGROUND: Coagulation factor V (FV) deficiency is a rare bleeding disorder that is usually managed with fresh-frozen plasma. Patients with nonsense mutations may respond to treatment with readthrough agents.
OBJECTIVE: To investigate whether the F5 p.Arg1161Ter mutation, causing severe FV deficiency in several patients, would be amenable to readthrough therapy.
METHODS: F5 mRNA and protein expression were evaluated in a F5 p.Arg1161Ter-homozygous patient. Five readthrough agents with different mechanisms of action, i.e. G418, ELX-02, PTC-124, 2,6-diaminopurine (2,6-DAP), and Amlexanox, were tested in in vitro and ex vivo models of the mutation.
RESULTS: The F5 p.Arg1161Ter-homozygous patient showed residual F5 mRNA and functional platelet FV, indicating detectable levels of natural readthrough. COS-1 cells transfected with the FV-Arg1161Ter cDNA expressed 0.7% FV activity compared to wild-type. Treatment with 0-500 μM G418, ELX-02, and 2,6-DAP dose-dependently increased FV activity up to 7.0-fold, 3.1-fold, and 10.8-fold, respectively, whereas PTC-124 and Amlexanox (alone or in combination) were ineffective. These findings were confirmed by thrombin generation assays in FV-depleted plasma reconstituted with conditioned media of treated cells. All compounds except ELX-02 showed some degree of cytotoxicity. Ex vivo differentiated megakaryocytes of the F5 p.Arg1161Ter-homozygous patient, which were negative at FV immunostaining, turned positive after treatment with all 5 readthrough agents. Notably, they were also able to internalize mutant FV rescued with G418 or 2,6-DAP, which would be required to maintain the crucial platelet FV pool in vivo.
CONCLUSIONS: These findings provide in vitro and ex vivo proof-of-principle for readthrough-mediated rescue of the F5 p.Arg1161Ter mutation.