Plasma Factor XIII Activity Research Articles

Coagulation factor XIII is a critical driver of liver regeneration after partial hepatectomy

BackgroundActivation of coagulation and fibrin deposition in the regenerating liver appears to promote adequate liver regeneration in mice. In humans, perioperative hepatic fibrin deposition is reduced in patients who develop liver dysfunction after partial hepatectomy (PHx), but the mechanism underlying reduced fibrin deposition in these patients is unclear. Methods and ResultsHepatic deposition of cross-linked (ie, stabilized) fibrin was evident in livers of mice after two-thirds PHx. Interestingly, hepatic fibrin cross-linking was dramatically reduced in mice after 90% PHx, an experimental setting of failed liver regeneration, despite similar activation of coagulation after two-thirds or 90% PHx. Likewise, intraoperative activation of coagulation was not reduced in patients who developed liver dysfunction after PHx. Preoperative fibrinogen plasma concentration was not connected to liver dysfunction after PHx in patients. Rather, preoperative and postoperative plasma activity of the transglutaminase coagulation factor (F)XIII, which cross-links fibrin, was lower in patients who developed liver dysfunction than in those who did not. PHx-induced hepatic fibrin cross-linking and hepatic platelet accumulation were significantly reduced in mice lacking the catalytic subunit of FXIII (FXIII−/− mice) after two-thirds PHx. This was coupled with a reduction in both hepatocyte proliferation and liver–to–body weight ratio as well as an apparent reduction in survival after two-thirds PHx in FXIII−/− mice. ConclusionThe results indicate that FXIII is a critical driver of liver regeneration after PHx and suggest that perioperative plasma FXIII activity may predict posthepatectomy liver dysfunction. The results may inform strategies to stabilize proregenerative fibrin during liver resection.

Distinguishing immune-mediated thrombotic thrombocytopenic purpura from septic disseminated intravascular coagulation using plasma levels of haptoglobin and factor XIII activity

BackgroundBoth immune-mediated thrombotic thrombocytopenic purpura (iTTP) and septic disseminated intravascular coagulation (DIC) are life-threatening disorders developed by platelet-consuming microvascular thrombi and necessitate immediate therapeutic interventions. Although severe deficiencies of plasma haptoglobin in iTTP and factor XIII (FXIII) activity in septic DIC have been reported, few studies have focused on the possibility of using these markers to distinguish between iTTP and septic DIC. ObjectivesWe investigated whether the plasma levels of haptoglobin and FXIII activity could be helpful for differential diagnosis. MethodsThirty-five patients with iTTP and 30 with septic DIC were enrolled in the study. Patient characteristics, coagulation, and fibrinolytic markers were collected from the clinical data. Plasma haptoglobin and FXIII activities were measured using chromogenic Enzyme-Linked Immuno Sorbent Assay and an automated instrument, respectively. ResultsThe median plasma haptoglobin level was 0.39 mg/dL and 54.20 mg/dL in the iTTP and septic DIC groups, respectively. The median plasma FXIII activities were 91.3% and 36.3% in the iTTP and septic DIC groups, respectively. In the receiver operating characteristic curve analysis, the cutoff level of plasma haptoglobin was 2.868 mg/dL and the area under the curve was 0.832. The cutoff level for plasma FXIII activity and the area under the curve were 76.0% and 0.931, respectively. The thrombotic thrombocytopenic purpura (TTP)/DIC index was defined by FXIII activity (percentage) and haptoglobin (milligrams per decilitre). Laboratory TTP was defined as an index ≥60 and laboratory DIC <60. The sensitivity and specificity of the TTP/DIC index were 94.3% and 86.7%, respectively. ConclusionThe TTP/DIC index, composed of plasma levels of haptoglobin and FXIII activity, is useful in differentiating iTTP from septic DIC.

Differential Diagnosis Distinguishing Immune TTP from Septic DIC Using Plasma Levels of Haptoglobin and Factor XIII Activity

Introduction Differential diagnosis of immune thrombotic thrombocytopenic purpura (iTTP) and septic disseminated intravascular coagulation (DIC) in daily clinical practice is difficult. iTTP is diagnosed by deficiency of ADAMTS13 activity and ADAMTS13 inhibitor positivity. However, it is difficult to rapidly measure ADAMTS13 activity in real-time in clinical practice. Prompt therapeutic interventions are directly dependent on iTTP prognosis. A method for differentiating between these two disorders using common laboratory tests is needed. Plasma haptoglobin levels can indicate hemolysis and are reported to be severely decreased in iTTP. Coagulation factor XIII (FXIII) activity is also severely decreased in septic DIC. To date, no reports have observed haptoglobin in septic DIC or FXIII activity in iTTP. We analyzed the plasma levels of haptoglobin and FXIII activity in patients with iTTP and septic DIC to investigate whether these markers can be used for differential diagnosis. Methods iTTP was defined as <10% normal ADAMTS13 activity, and >0.5 BU/mL ADAMTS13 inhibitor. Septic DIC was defined as meeting both Third International Consensus Definitions for Sepsis and Septic Shock, and ISTH DIC diagnostic criteria. Thirty-five patients with iTTP and 30 with septic DIC were enrolled in this study. Plasma haptoglobin levels were measured using Human Quantikine ELISA Kits (#DPHAGO, R&D Systems, Inc., Minneapolis, USA), which is a highly sensitive method compared to methods used in clinical practice. Values are expressed as medians (first quartile-third quartile). Results As shown in the table, iTTP patients were significantly younger than those with septic DIC. The iTTP group showed significantly lower ADAMTS13 activity, higher ADAMTS13 inhibitor titer, lower hemoglobin level, lower platelet counts, higher LDH level, and lower creatinine level than the septic DIC group. In a comparison of coagulation and fibrinolytic markers, the septic DIC group had significantly higher PT-INR, prolonged APTT, higher FDP and D-dimer levels, and lower AT activity than the iTTP group. The plasma haptoglobin level was 0.39 mg/dL (0.18-0.76 mg/dL) in the iTTP group, and 54.2 mg/dL (0.6-143.9 mg/dL) in the septic DIC group (P < 0.01). FXIII activity was 91.3% (80.4-115.0%) in the iTTP group, and 36.3% (14.7-61.9%) in the septic DIC group (p<0.01). The ROC curve of haptoglobin and FXIII activity in the differential diagnosis of TTP and septic DIC were investigated. The cut-off level of haptoglobin was 2.868 mg/dL, the area under the curve (AUC) was 0.832 (95% CI:0.727-0.938), specificity was 66.7%, and sensitivity was 100%. The cutoff level of FXIII activity was 76.0%, AUC was 0.931 (95%CI:0.873-0.989), specificity was 77.1%, and sensitivity was 93.3%. We developed a scoring system to differentiate iTTP from septic DIC using a combination of FXIII activity and haptoglobin; TTP/DIC index = plasma FXIII activity (%) - plasma haptoglobin (mg/dL). Laboratory TTP was defined when the index was ≥60, and laboratory DIC was defined when the index was <60. The AUC for the combination of FXIII activity and haptoglobin was 0.968 (95% CI: 0.9354-1). The accuracy of iTTP diagnosis in laboratory TTP was 89.2% (33/37), and the accuracy of septic DIC diagnosis in laboratory DIC was 92.9% (26/28). Conclusions A comparison of iTTP and septic DIC showed significant differences in haptoglobin and FXIII activity levels. A combination of haptoglobin and FXIII activity was considered helpful in differentiating iTTP from septic DIC. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

Factor XIII and Fibrin Clot Properties in Acute Venous Thromboembolism.

Coagulation factor XIII (FXIII) is converted by thrombin into its active form, FXIIIa, which crosslinks fibrin fibers, rendering clots more stable and resistant to degradation. FXIII affects fibrin clot structure and function leading to a more prothrombotic phenotype with denser networks, characterizing patients at risk of venous thromboembolism (VTE). Mechanisms regulating FXIII activation and its impact on fibrin structure in patients with acute VTE encompassing pulmonary embolism (PE) or deep vein thrombosis (DVT) are poorly elucidated. Reduced circulating FXIII levels in acute PE were reported over 20 years ago. Similar observations indicating decreased FXIII plasma activity and antigen levels have been made in acute PE and DVT with their subsequent increase after several weeks since the index event. Plasma fibrin clot proteome analysis confirms that clot-bound FXIII amounts associated with plasma FXIII activity are decreased in acute VTE. Reduced FXIII activity has been associated with impaired clot permeability and hypofibrinolysis in acute PE. The current review presents available studies on the role of FXIII in the modulation of fibrin clot properties during acute PE or DVT and following these events. Better understanding of FXIII’s involvement in the pathophysiology of acute VTE might help to improve current therapeutic strategies in patients with acute VTE.

Factor XIIIa Formation Promoted by Complexing of a-Thrombin, Fibrin, and Plasma Factor XIII

Fibrin polymers (des A,B fibrinogen) reduced the concentration of alpha-thrombin required for 50% activation of plasma factor XIII (a2b2 tetramer) by approximately 100-fold. In the presence of fibrin, the amount of gamma-thrombin required for activation was not affected. Catalytically inactive i-Pr2P- and D-Phe-Pro-Arg-CH2-alpha-thrombin were found to inhibit over 95% of the activation by alpha-thrombin in the presence of fibrin. Unlike plasma factor XIII, the concentration of alpha-thrombin required for 50% activation of platelet factor XIII (a2 dimer) was lower, and the activation was not enhanced by fibrin. However, when the a2 platelet factor XIII was incubated with purified b-chains, the alpha- and gamma-thrombin concentrations required for activation increased tenfold and reached levels similar to those required for activation of the plasma factor XIII. When fibrin was present, the alpha-thrombin concentrations needed for activation of the a2b2 complexes were reduced, and the presence of fibrin had no effect on gamma-thrombin cleavage of the a2b2 complexes. Therefore, the b-chains must inhibit a-chain cleavage by alpha-thrombin in the absence of fibrin. These results imply that the formation of a cocomplex involving alpha-thrombin, fibrin, and plasma factor XIII causes some conformational change in plasma factor XIII such that the b-chains no longer inhibit cleavage of the a-chains.

Plasma fibrin clots of pulmonary embolism patients present increased amounts of factor XIII and alpha2-antiplasmin at 3 months' anticoagulation since the acute phase.

Fibrin cross-linking by coagulation factor (F)XIII leads to clot stabilization. Reduced plasma FXIII levels have been reported in acute pulmonary embolism (PE) patients. We investigated the impact of anticoagulant therapy on clot-bound amounts of FXIII and α2-antiplasmin and their associations with fibrin clot properties in patients with PE. Clots generated from plasma of 18 acute symptomatic patients on admission and after a 3-month treatment with rivaroxaban were assessed off anticoagulation using mass spectrometry. Plasma FXIII and α2-antiplasmin activity were determined at the 2 time points along with thrombin generation markers, plasma fibrin clot permeability (Ks), and clot lysis time (CLT). Following anticoagulant therapy, clot-bound FXIII increased from 2.97 (interquartile range, 1.98 - 4.08) to 4.66 (3.5 - 6.9) mg/g protein and α2-antiplasmin from 9.4 (7.2 - 10.6) to 11 (9.5 - 14) mg/g protein (both p < 0.0001). The two parameters showed positive correlation at baseline only (r = 0.63, p = 0.0056). Similarly to clot-bound amounts, plasma FXIII (+25.8%) and α2-antiplasmin activity (+12%) increased at 3 months. Plasma FXIII activity on admission, but not after 3 months since the index PE, was associated with amounts of clot-bound FXIII (r = 0.35, p = 0.043) and α2-antiplasmin (r = 0.47, p = 0.048). At baseline, clot-bound FXIII correlated with plasma F1+2 prothrombin fragments levels (r = 0.51, p = 0.03), while clot-bound α2-antiplasmin correlated with CLT (r = 0.43, p = 0.036). At 3 months associations of clot-bound FXIII and α2-antiplasmin were abolished. This study assessed for the first time changes in the fibrin clot composition following acute PE, suggesting an increase of clot-bound and plasma FXIII and α2-antiplasmin levels after 3 months.

Long-term prophylaxis in patients with severe congenital factor XIII deficiency is not complicated by inhibitor formation.

: Congenital factor XIII (FXIII) deficiency is a rare bleeding disorder accompanied by a variety of bleeding events. Severely deficient patients require regular replacement therapy. With development of FXIII concentrate, the risk of viral infections transmitted by fresh frozen plasma and cryoprecipitate is diminished, but the possibility of inhibitor development remains a challenging issue in the management of these patients. The aim of this study was to assess FXIII inhibitor development in Iranian patients with FXIII deficiency (FXIIID). This study enrolled 50 (30 women and 20 men) patients with severe congenital FXIIID from southeast Iran who underwent long-term (more than 4 years or more than 50 injections) prophylaxis with FXIII concentrate (Fibrogammin P, Dade Behring, Marburg, Germany). We evaluated plasma FXIII activity and FXIII inhibitor on day 28 after the last prophylaxis administration. The method for investigation of FXIII inhibitor was based on Bethesda assay. The mean age of the study population was 13.8 ± 8.3 years. The minimum and maximum FXIII activity levels were less than 1-4.5% (mean ± SD, 2.6 ± 0.7%). Our investigations showed that all patients with severe form of FXIIID were treated without inciting inhibitor development. Despite long-term prophylaxis in the studied patients, none was found to have developed FXIII inhibitors.

Regulation of plasma factor XIII levels in healthy individuals; a major impact by subunit B intron K c.1952 + 144 C > G polymorphism

BackgroundThe regulation of plasma factor XIII (FXIII) levels in healthy individuals has been only partially explored. The identification of major non-genetic and genetic regulatory factors might provide important information on the contribution of FXIII to the risk of cardio/cerebrovascular diseases. ObjectivesTo determine the effect of age, smoking, BMI, fibrinogen concentration on plasma FXIII activity, complex FXIII antigen (FXIII-A2B2) and total FXIII-B subunit (tFXIII-B) level, to correlate FXIII-B level with the other two FXIII parameters and to assess the variation of FXIII levels in carriers of major FXIII subunit polymorphisms. Methods268 healthy individuals were enrolled in the study. FXIII activity was measured by the ammonia release assay; FXIII-A2B2 and tFXIII-B were determined by ELISAs. FXIII-A p.Val34Leu, FXIII-B p.His95Arg and FXIII-B intron K c.1952+144 C>G polymorphisms were identified by RT-PCR using melting point analysis with fluorescence resonance energy transfer detection. ResultsAll investigated FXIII parameters showed significant positive correlation with age and fibrinogen level; gender and BMI influenced only tFXIII-B. A highly significant positive correlation was demonstrated between tFXIII-B and the other FXIII parameters. FXIII-A p.Val34Leu polymorphism had only slight, if any effect on FXIII levels. The FXIII-B Arg95 allele moderately increased all three FXIII parameters, but the effect became statistically significant only after adjustment. The FXIII-B intron K G allele drastically decreased FXIII levels, and it seemed to be in synergism with the FXIII-A Leu34 allele. ConclusionsPlasma FXIII levels are subjected to multifactorial regulation, in which age, fibrinogen level and FXIII-B intron K polymorphism are major determinants.

Clinical Use of Factor XIII Concentrates.

Factor (F) XIII deficiency is a congenital rare bleeding disorder (RBD), with an estimated prevalence of 1 in 1 to 2 million individuals, and more than 1,200 patients have been diagnosed to date. In newborns, umbilical cord bleeding is typical, and later in life during trauma, surgery and even spontaneously prolonged bleeds, reproduction, and delivery complications occur frequently without appropriate replacement therapy. Also, an acquired form of FXIII deficiency may occur via massive bleeds or neutralizing antibodies. In the inherited form of FXIII deficiency, prophylaxis with FXIII concentrate is administered to prevent the very high risk of intracranial bleeds, the incidence being close to 30%. Laboratory diagnosis of FXIII deficiency is based on measuring plasma FXIII antigen and activity, and it is claimed that FXIII activity of around 5 IU/dL would suffice to protect from bleeds. However, at the low levels of detection, most FXIII methods are inaccurate, and quality controls and collaboration with reference laboratories are important to improve the accuracy of low-level FXIII measurements. The trough target for prophylaxis should be set to 10 to 20 IU/dL, which is achievable by administration of 25 to 35 IU/kg every 4 to 6 weeks. However, general risk factors influencing hemostasis should be carefully evaluated, including anemia and hypertension. Fibrin cross-linking by FXIII is of major importance and red cells bind to fibrin partially via platelets and FXIII to promote clot strength. Physiologically, platelets and macrophages contain FXIII providing cellular support; thus, the patients may benefit from platelet transfusion during problematic bleeds. Plasma-derived and recently a recombinant FXIII concentrate are available; however, the latter has mainly anecdotal data regarding management of bleeds and surgery, and its access is limited due to the high cost. The international registry RBD database, (RBDD) continues to gain cumulative knowledge, and registration of all FXIII deficient patients, both inherited and acquired, is highly recommended.

Preoperative plasma fibrinogen concentration, factor XIII activity, perioperative bleeding, and transfusions in elective orthopaedic surgery: A prospective observational study

BackgroundMajor orthopaedic surgery involves a calculated risk of bleeding. In other groups of surgical patients, low preoperative plasma fibrinogen concentration and factor XIII (FXIII) activity have been associated with an elevated risk of bleeding. In the present study we investigated the association between preoperative fibrinogen plasma concentration and FXIII activity on bleeding and transfusion requirements in patients undergoing a spinal fusion procedure or hip or knee arthroplasty. MethodsTwo hundred and forty-five adult patients undergoing spine fusion surgery (n=52), total unilateral primary hip arthroplasty (n=114), or total knee arthroplasty (n=79) were included in a prospective observational study. Blood samples were collected <24h before surgery and analysed for fibrinogen concentration and FXIII activity. Intraoperative and postoperative bleeding volume and transfusion requirements were recorded. ResultsSpinal fusion surgery patients with a low preoperative fibrinogen concentration (≤2.5g/L) had a greater total perioperative median bleeding volume than patients with fibrinogen>2.5g/L (2430 (400–6560) mL vs. 1390 (400–7420) mL, p=0.029). No significant association between low fibrinogen levels and perioperative bleeding volume was observed for arthroplasty patients. There was no association between low fibrinogen levels and transfusion requirements in any of the groups. Low FXIII activity was not significantly associated with bleeding volume and transfusion requirements in any group. ConclusionMeasurement of preoperative fibrinogen plasma concentration can identify spinal fusion patients with an increased risk of excessive perioperative bleeding. Measurement of FXIII activity cannot identify orthopaedic patients with elevated risk of bleeding.

This Is a Title : Long Term succsesfull Prophylaxis in 190 Patients with Severe Congenital Factor XIII Deficiency, a Four Years Experience. Here Is the Sub-Title: Succsefull Prophylaxis in Factor XIII Deficiency

▪Background:factor XIII deficiency (FXIIID) is an extremely rare bleeding disorder with an estimated incidence of 1 per 1 to 3 million that transmitted in an autosomal recessive manner. The disorder is characterized by severe bleeding diathesis, impaired wound healing and recurrent spontaneous miscarriage. Sistan and Baluchistan Province in south east of Iran with high rate of consanguineous marriages has the highest incidence of FXIIID around the world. The aim of this study was to evaluate clinical manifestations and prophylaxis therapy in FXIII deficient patients with life threatening complications and to assess the risk of FXIII inhibitor development in patients with long term prophylaxis. We also investigated prophylaxis treatment in neonates with FXIIID.Methods:This study was conducted on 190 patients with FXIIID from southeast of Iran. Diagnosis of FXIIID was based on factor activity and molecular investigation of Trp187Arg which is the only reported mutation of FXIII in this region. We also selected some cases for sequencing to confirm the molecular results.Patients underwent regular prophylaxis and the efficacy of prophylaxis was assessed by prospective follow-up in duration of 4 years. The frequency of bleeding episodes as described by Tosetto et al. was recorded before and after prophylaxis each month. Patients with Intracranial hemorrhage (ICH) received Fibrogammin P® in a dose of 30 IU/Kg every 4 day as prophylaxis and in a dose of 10-26 IU/kg when ICH occurred. Patients with miscarriage underwent regular prophylaxis with FXIII concentrate with a dose of 10 IU/Kg every 2 weeks during pregnancy and also received the same dose as prophylaxis before gestation in 4 week intervals.In cases that had a history of prophylaxis for more than 4 years or had more than 50 injections, development of FXIII inhibitor was investigated by Bethesda assay. We evaluated plasma FXIII activity and FXIII inhibitor in day 28 after the last prophylaxis administration by Cobas Mira device. This assay was performed on a large amount of population for the first time. If the result of inhibitor was negative the test was replicated with 3 dilutions.We also enrolled 34 neonates with FXIIID to the study and divided them into two groups. Group 1 (17 neonates) received a standard dose of Fibrogammin (10-26 IU/Kg) while group 2 (17 neonates) received a dose of 60-80 IU/Kg. We followed both groups for 36 months and the frequency of bleeding episodes was recorded for each group and compared using independent t-test. Neonates in group 2 were assessed for thrombotic events promptly after administration of Fibrogammin P®, the following day and one week later.Results:Plasma FXIII activity in all patients was undetectable which is suggestive of severe deficiency. Genetic analysis revealed a homozygous Trp187Arg mutation in all patients and it was in agreement with the sequencing results of selected cases. Clinical manifestation of patients and the bleeding score of different diathesis before and after prophylaxis are indicated in table 1. Forty nine patients had the defined criteria for investigation of FXIII inhibitor development. Among them 14 had experienced ICH. Despite long term prophylaxis in these patients none of them was detected to develop FXIII inhibitors.No patient with ICH experienced this phenomenon after prophylaxis treatment.The majority of patients with miscarriage only experienced this diathesis once (62.5%). The prophylaxis program was successful in management of pregnancy in all 8 patients.Comparison of two neonate groups revealed that bleeding episodes in group 2 were significantly lower than group 1 (p<0.05). We did not observe any thrombotic event in group 2, which is an important finding in safety of Fibrogammin P® also in prevention of potential loss of drug.Conclusion:Fibrogammin P® is effective in the management of FXIIID and surprisingly long term prophylaxis in the patients did not lead to development of FXIII inhibitor. Furthermore higher dose of Fibrogammin P® is safe and effective in neonates.Table 1Clinical manifestations and Tosetto bleeding scores of different bleeding diathesis before and after prophylaxis.Number of affected patients (%)Score before prophylaxisScore after prophylaxisUmbilical bleeding157(82.5)123Hematoma101 (53)122ICH32(17%)143Epistaxis26(14%)112Ecchymosis25 (12.5%)122Hemarthrosis7 (4%)132Miscarriage8 (5%)-- DisclosuresNo relevant conflicts of interest to declare.

Clinical value of exogenous factor XIII for prolonged air leak following pulmonary lobectomy: a case control study.

BackgroundWe examined the effect of exogenous factor XIII (FXIII) concentrate in patients with prolonged air leak (PAL) after pulmonary lobectomy for non-small cell lung cancer.MethodsWe performed a retrospective analysis of 297 patients who underwent pulmonary lobectomy between July 2007 and March 2014: 90 had an air leak on the first postoperative day, which resolved spontaneously within 5 days in 53 cases (SR group). FXIII concentrate was administered to the remaining 37 patients (PAL group) for 5 days. This group was subdivided into those in whom the air leak resolved during FXIII treatment (EF group) and those who needed additional intervention (inEF group). The clinical and perioperative characteristics of the groups were compared.ResultsAlthough plasma FXIII activity did not differ significantly between the SR and PAL groups before surgery or on the fifth postoperative day, the proportional perioperative fall in FXIII activity was significantly greater in the SR group (33%) than the PAL group (22%, p = 0.044) and inEF group (14%, p = 0.048). On the fifth postoperative day, FXIII activity was significantly lower in the EF group than in the inEF group (74% versus 91%, p = 0.030). The optimal cut-off point for postoperative plasma FXIII activity to distinguish between the EF and inEF groups was 86%.ConclusionsInsufficient plasma FXIII consumption and lower postoperative FXIII activity may play a role in the resolution of PAL, and exogenous FXIII concentrate may be an effective, safe and non-invasive treatment.

Changes in factor XIII level during pregnancy

Pregnancy is associated with significant haemostatic changes, with a progressive rise in most clotting factors. There is limited data on the changes of factor XIII (FXIII) level during pregnancy. This study assesses changes in FXIII activity during normal pregnancy and establish FXIII reference range during each trimester of pregnancy and immediate postnatal period. This is a cross sectional study of 376 women with normal uneventful pregnancies. Plasma FXIII activity was measured during first (weeks 0-12, n = 116), second (weeks 13-28, n = 132), third trimester (weeks 29-42, n = 128) and postnatal (day 0-3; n = 30). Samples were also collected from non-pregnant women (n = 25) as a control group. FXIII was assayed on CS-5100 analyser using chromogenic reagent. The mean ± SD FXIII activity was 112 ± 29 IU dL(-1) during first trimester, 96 ± 26 IU dL(-1) during second trimester, 83 ± 21 IU dL(-1) during third trimester, 90 ± 19 IU dL(-1) during postnatal period, and 113 ± 26 IU dL(-1) in the control. The reference range was calculated during the first (55-169 IU dL(-1)), second (45-147 IU dL(-1)), third trimester (42-125 IU dL(-1)) and postnatal period (61-137 IU dL(-1)). There was a significant reduction in the mean FXIII activity during the second and third trimester compared to the first trimester and control group (P < 0.0001). During the immediate postnatal period, the mean FXIII activity was not statistically different compared to the third and second trimester levels but was significantly lower compared to the first trimester (P < 0.0001) level and the control group (P = 0.0002). This study establishes the reference range for FXIII activity during the three trimesters of normal pregnancy and immediate postnatal period. Women have a significantly decreased level of FXIII activity during a normal uneventful pregnancy.

Plasma FXIII LEVEL Variations During Menstrual CYCLE

Introduction Factor XIII (FXIII) has an important role in the control of bleeding through fibrin cross-linking. While many physiological factors affect plasma FXIII level, the effect of the menstrual cycle is not fully understood.Aim: The study aimed to assess possible changes in plasma FXIII activity during the normal menstrual cycle and to assess any correlation between FXIII activity during the menstrual phase and the menstrual blood loss. Methods In this longitudinal study, a total of 32 women of reproductive age were recruited. Menstrual blood loss was measured using the pictorial blood-assessment chart (PBAC). A bleeding questionnaire and score were also completed. Blood samples were taken during menstrual phase (day 1-5), proliferative phase (day 6-11), periovulatory phase (day 12-17), secretory phase (days 18-23), and premenstrual phase (day 24-29) for assessment of FXIII level using quantitative ammonia release assay. Results Mean FXIII level was significantly lowest during menstrual and periovulatory phases of the cycle (114 IU/dL) compared to secretory (121 IU/dL) and premenstrual (122 IU/dL) phases (p=0.036). No significant correlation between FXIII activity during menstrual phase and women age (p= 0.53) or PBAC score (p=0.53). Among 14 women with PBAC score ≥ 100, the median FXIII activity during the menstrual phase of the cycle was 116 IU/dL, this was not statistically different from group with PBAC score &lt;100 (113 IU/dL) (p = 0.72). Conclusion FXIII activity was lowest during the menstrual and periovulatory phases of the cycle. Understanding these changes in FXIII during menstrual cycle will help clinicians to perform blood tests during appropriate phase of the menstrual cycle and to capture the baseline level. Disclosures: Halimeh: Octapharma AG: Investigator Other, Research Funding.

Tocilizumab Induced Acquired Factor XIII Deficiency in Patients with Rheumatoid Arthritis

Factor XIII is one of the twelve coagulation factors and also known as a fibrin-stabilizing factor. In 2012, we encountered a male RA patient with hemorrhagic factor XIII deficiency who had been treated with tocilizumab for two years. There are few reports regarding the relationship between tocilizumab (a humanized monoclonal antibody against the interleukin-6 receptor (IL-6R)) and factor XIII. We measured the factor XIII activity levels in the plasma of 40 RA patients (10 patients treated without biologics, 30 patients treated with biologics (15 patients treated with necrosis factor inhibitors and 15 patients treated with tocilizumab)) and 19 healthy controls. Consequently, the tocilizumab group exhibited lower levels than the other three groups according to the Steel-Dwass test (P<0.01). Furthermore, we compared the plasma factor XIII activity levels and the plasma factor XIII concentrations in the RA patients treated with biologics. Pearson's correlation test was used to assess the relationship between the factor XIII activity levels and the plasma factor XIII concentrations (r = 0.449, P = 0.019). According to the multiple regression analysis, the treatment with tocilizumab is an independent risk factor for plasma factor XIII reduction in RA patients. In conclusion, RA patients treated with tocilizumab, an IL-6R blocker, are at risk of developing acquired factor XIII deficiency. The mechanisms underlying the reduced factor XIII activity observed in RA patients treated with tocilizumab may result from the quantitative reduction in the plasma. These data imply that IL-6 plays an important role in maintaining the factor XIII activity level.

Clinical Significance of Blood Coagulation Factor XIII Activity in Adult Henoch-Sch&amp;ouml;nlein Purpura

A correlation between decreased blood coagulation factor XIII activity and the severity of organ disorders in pediatric Henoch-Schönlein purpura (HSP) has been demonstrated, but possible correlations in adult HSP have not been thoroughly investigated. To investigate the association between factor XIII activity with varying clinical severities of HSP and the severity of organ disorders and to examine the efficacy of factor XIII substitution therapy. The distribution of purpura and the severities of joint, abdominal, and renal symptoms were scored in 44 adults with HSP. Plasma factor XIII activity was measured with the latex agglutination immunoturbidity method. Reduced factor XIII activities were correlated with clinical severity scores (the total of all scores), organ disorder severity scores (the total score excluding the purpura score), joint symptom scores, and abdominal symptom scores but not with renal disorder scores. Factor XIII activities were increased in patients during posttreatment remission. Factor XIII substitution therapy was performed in 7 patients with severe organ disorders. Consequently, joint and abdominal symptoms markedly improved, but renal symptoms did not. Measurement of plasma factor XIII activity in adult HSP is clinically useful because it indicates disease severity and the severity of digestive tract and joint disorders. Factor XIII substitution therapy is effective for joint and abdominal symptoms but not for renal symptoms. Further investigation of the effect of this treatment on renal symptoms is necessary.

Factor XIII expression within aortic valves and its plasma activity in patients with aortic stenosis: association with severity of disease

Aortic valve stenosis (AS) shares several similarities with atherosclerosis. Factor XIII (FXIII) has been detected within atherosclerotic plaques and may contribute to the development of atherosclerosis via multiple mechanisms. In the current study, we sought to investigate FXIII expression within human stenotic aortic valves and its association with severity of the disease. We prospectively enrolled 91 consecutive patients with AS scheduled for isolated valve replacement. Valvular FXIII subunit A (FXIII-A), fibrin and macrophages expression was evaluated by immunostaining. FXIII-A subunit transcripts and FXIII-A Val34Leu polymorphism was determined by real-time PCR. Plasma FXIII (pFXIII) activity was measured. We demonstrated that the valvular FXIII-A was predominantly expressed on the aortic side of leaflets, colocalized with alternatively activated macrophages (AAM). Areas stained for FXIII-A showed positive correlations with valvular fibrin presence, degree of calcification, pFXIII activity and the severity of AS, reflected by mean and maximum transvalvular gradients (all, p<0.001). The FXIII-A mRNA in the stenotic leaflets was significantly elevated compared to control leaflets. Interestingly, pFXIII activity was also positively correlated with mean (p<0.001) and maximum (p=0.001) transvalvular gradient. The FXIII-A Val34Leu polymorphism did not affect FXIII-A and fibrin expression in AS valves. In conclusion, the study is the first to show abundant expression of FXIII-A at the mRNA and protein levels within human stenotic aortic valves, which is associated with the severity of AS. Our findings might suggest that FXIII in the stenotic valves is presented in AAM and may be involved in the AS progression.

A Novel Nonsense Mutation of F13A1 Gene Causing Inherited Factor XIII Deficiency in a Chinese Han Family

Abstract 4661 Introduction:Coagulation factor XIII (FXIII) is a protransglutaminase that has a major role in the final stage of blood coagulation process by forming cross-links between γ-glutamyl and ε-lysine residues of fibrin chains. The plasma FXIII (pFXIII) circulates in plasma as a heterotetramer (FXIII-A2B2) consisting of two catalytic A subunits (FXIII-A2) and two carrier B subunits (FXIII-B2). Inherited FXIII deficiency is a rare autosomal recessive disease with lifelong bleeding. Most cases of FXIII deficiency are heterogeneous due to mutations in the F13A gene. Currently, more than 100 mutations have been reported. Aim:To identify the genetic defect of inherited coagulation factor XIII (FXIII) deficiency in a Chinese Han family. Methods and Results:A 13 year-old patient complained of poor wound healing after operation and had a history of an excessive bleeding from the umbilical cord stump after her birth. The routine laboratory tests are normal. Her bleeding time is more than 15 minutes and fibrin clot was solubilized very quickly in 5mol/L urea, and became insoluble when normal plasma was mixed with her plasma in vitro. Her plasma FXIII activity was zero with the amine incorporation assay and plasma FXIII antigen was also near zero by one-step sandwich ELISA method, the plasma FXIIIA antigen was zero using an indirect competitive ELISA assay. The plasma FXIIIA antigen, FXIII activity and antigen were assayed in all available family members. The testing results of patient's grandfather and maternal grandmother were within normal range. But the other pedigree members' results were lower in different level compare with normal ranges. All members of her family had normal coagulation test.All the exons of F13A gene as well as F13B gene and their flanking regions were amplified by PCR for direct sequencing to identify the mutations in the proband. Direct DNA sequencing of all purified amplification products from the patient's F13A gene demonstrated a homozygous nonsense mutation in exon8 (C to A transversion at nucleotide 98531 which caused Cys327X). And the patient didn't have the Val34Leu polymorphism. In the pedigree except of the proband, the Cys327X mutation was found in the heterozygous state in all investigated members except for her grandfather and maternal grandmother. A family study revealed that the mutation was inherited from both parents.The identified mutation was validated by PCR-RFLP technique in the family members and healthy people. Restriction enzyme analysis of amplified exon 8 DNA fragment confirmed that the patient was homozygous for this mutation. Then the quantitative RT-PCR method was used for studying the mRNA expression level of mutant FXIIIA. And the results indicated that F13A mRNA transcripts in heterozygous mutant were reduced by 25% when compared to transcripts in wild-type one, while the homozygous mutant level of F13A mRNA transcript was nearly zero relative to the normal transcript. Conclusion:We have identified a novel Cys327X nonsense mutation in human FXIIIA gene which we have not found in the FXIII database (www.f13-database.de) or in previous publications.And the identified nonsense mutation is causative for severe factor XIII deficiency with a bleeding disorder. Further, in vitro expression studies of the factor XIII mutation is required to confirm their pathological mechanism. Disclosures:No relevant conflicts of interest to declare.

A Novel 3-Base Pair 1834–1836 AAG-Deletion (Lys570Del) Mutation In Factor XIII A Subunit Associated with Factor XIII Deficiency

AbstractAbstract 1412Factor XIII is a transglutaminase that cross-links proteins in plasma, vascular matrix, endothelial cells, platelets and monocytes, and plays a role in atherosclerosis, wound healing, and inflammation. Plasma FXIII molecule is a hetero-tetramer consisting of two catalytic A-subunits and two B-subunits that act as carrier molecules. The gene encoding FXIII A subunit comprises of 15 exons spanning 160 kb and the mature protein contains 731 amino acids. FXIII deficiency is a rare autosomal recessive disorder affecting ∼1 in 1–3 million people. It is characterized by bleeding, impaired wound repair and spontaneous abortions. We report studies from a family where two children son (13 yrs) and daughter (11 yrs) have had a lifelong bleeding tendency and spontaneous intracranial hemorrhages. Both parents were asymptomatic and there was no consanguinity. The results of routine laboratory tests, prothrombin time and activated partial thromboplastin time were normal in all subjects. The plasma FXIII activity by a commercially available chromogenic assay was 5% in the son and <3% in the daughter (normal range 57–192%). The FXIII activity in the father and mother were 198% and 74%, respectively. We have identified a novel deletion mutation, which has not been reported so far in FXIII deficiency. Leukocyte RNA was isolated from the buffy-coat and cDNA was obtained by reverse-transcription PCR using SuperScript First-Strand Synthesis System. The amplified products were cloned in pGEM-T vector (Promega) and sequenced on an automated gene-sequencer. Both children and the father have a novel 3 bp AAG-deletion position 1834–1836 nt in FXIII A chain. This mutation causes a lysine 570 deletion in the ß-barrel 1 of Factor XIII A subunit and has not been reported so far. It may lead to protein misfolding resulting in an unstable protein, and low levels of FXIII. The second major change detected in the two siblings was a A/T substitution at position 737 nt causing Tyr204Phe substitution in the two siblings; this was present in the mother in a heterozygous condition. This mutation has been previously reported in FXIII deficiency and linked to increased risk of haemorrhagic stroke in young women and of miscarriages. The compound heterozygosity for Lys570Del and Tyr204Phe substitution observed in both children is the likely cause of Factor XIII deficiency leading to lifelong bleeding condition. In addition to above, the father had Val34Leu polymorphism, previously reported to be associated with resistance to myocardial infarction. This polymorphism is present in ∼20% of white European, 40% of Pima Native American and 13% of South Asian populations. The mother also had a known A/C polymorphism at 1119 nt position for a synonymous Pro332Pro change. We also found 3 other variations in FXIII A chain in this family. The daughter has Glu216Gly and Asp267Asn change in the protein corresponding to alterations at nucleotide 773 (A/G) and 925 (A/G), respectively. The son and mother had a substitution at 1442 nt (T/C) leading to a Leu439Pro change. These variations, Glu216Gly, Asp267Asn and Leu439Pro found in the two children (Leu439Pro also in mother) are present in the catalytic core domain of the Factor XIII A chain. All of the polymorphisms or mutations reported in this study were heterozygous in the studied subjects. FXIII gene mutations and polymorphisms result in a high level of heterogeneity of disease presentation. Other point mutations in the FXIII A catalytic core as well as mutations in ß-barrel 1 region have been described in association with a hemorrhagic state in FXIII deficiency. Our study documents a new 3-bp 1834–1836 nt AAG-deletion (Lys570Del) in association with FXIII deficiency. We suggest that compound heterozygosity for Lys570Del and Tyr204Phe is the cause of FXIII deficiency in our patients. Further structure-function studies will aid in understanding the impact of these amino acid substitutions or deletions on FXIII function and on the associated bleeding diathesis. Disclosures:No relevant conflicts of interest to declare.

Henoch-Schönlein Purpura in a Child With Guillain-Barré Syndrome

A case of Henoch-Schönlein purpura with Guillain-Barré syndrome in a 3-year-old-girl is presented. This association is extremely rare. During the course of Guillain-Barré syndrome, a decrease in plasma factor XIII activity was noted. When the Guillain-Barré symptoms improved, the factor XIII activity returned to normal. In the present case of Henoch-Schönlein purpura complicated by Guillain-Barré syndrome, the factor XIII level was measured, a novel feature of this study. The findings suggest the involvement of factor XIII, which is characteristically involved in Henoch-Schönlein purpura, also is involved in the associated Guillain-Barré syndrome.