Human Factor VIII Inhibitor Alloantibodies with a C2 Epitope Inhibit Factor Xa-catalyzed Factor VIII Activation: A new Anti-factor VIII Inhibitory Mechanism

2002 ◽  
Vol 87 (03) ◽  
pp. 459-465 ◽  
Author(s):  
Keiji Nogami ◽  
Katsumi Nishiya ◽  
Yoshihiko Sakurai ◽  
Ichiro Tanaka ◽  
John Giddings ◽  
...  
Keyword(s):  
Factor Viii ◽  
Factor Xa ◽  
Factor Viii Inhibitor ◽  
Inhibitory Mechanism ◽  
Fviii Inhibitor ◽  
Fviii Activity ◽  
Human Factor Viii ◽  
Sds Page ◽  
Viii Inhibitor ◽  
C1 Domains

SummaryFactor VIII (FVIII) inhibitor alloantibodies react with the A2, C2, or A3-C1 domains of FVIII and inactivate FVIII activity. We recently demonstrated that an anti-C2 monoclonal antibody with a Val2248Gly2285 epitope, inhibited factor Xa (FXa)-catalyzed FVIII activation, and that a FXa binding site for FVIII was located within residues Thr2253-Gln2270. In this study, we investigated whether anti-C2 alloantibodies inhibit FXa-catalyzed FVIII activation. Anti-C2 alloantibodies from four patients inhibited FVIII activation by FXa in onestage clotting assay. Furthermore, analysis by SDS-PAGE showed that all alloantibodies inhibited FVIII proteolytic cleavage by FXa independently of phospholipid. To confirm direct inhibition of FVIII and FXa interaction, we examined the effect of alloantibodies on FVIII binding to anhydro-FXa, a catalytically inactive FXa, in ELISA. All alloantibodies and C2-affinity purified F(ab)’2 preparations inhibited FVIII binding to anhydro-FXa dose-dependently. Our results revealed a new inhibitory mechanism of FVIII, mediated by inhibition of FXa in the presence of anti-C2 alloantibodies.

Non-Classical Anti-Factor VIII C2 Domain Inhibitors Are Present in the Plasmas of Most Factor VIII Inhibitor Patients.

Blood ◽  
2007 ◽  
Vol 110 (11) ◽  
pp. 786-786
Author(s):  
Shannon L. Meeks ◽  
John F. Healey ◽  
Rachel T. Barrow ◽  
Ernest T. Parker ◽  
Pete Lollar
Keyword(s):  
Factor Viii ◽  
Hemophilia A ◽  
Factor Viii Inhibitor ◽  
C2 Domain ◽  
Proteolytic Activation ◽  
Autoimmune Antibodies ◽  
Fviii Inhibitor ◽  
Fviii Activity ◽  
Viii Inhibitor ◽  
Murine Mabs

Abstract Approximately 30% of patients with severe hemophilia A will develop inhibitory antibodies to factor VIII (fVIII inhibitors). The immune response to fVIII currently is the most significant complication in the management of patients with hemophilia A. In addition, autoimmune antibodies to fVIII can develop in non-hemophiliacs, producing acquired hemophilia A, which frequently produces life- or limb-threatening bleeding. These inhibitors primarily are directed against the A2 or C2 domains of fVIII. The human response to the C2 domain of fVIII classically has been thought to inhibit fVIII activity by blocking its binding to phospholipid. We recently characterized the antibody response to the C2 domain of human fVIII in a murine hemophilia model and described 5 structural groups of antibodies. Groups A, AB, and B are classical anti-C2 antibodies. Groups BC and C consist of non-classical anti-C2 antibodies that inhibit the proteolytic activation of fVIII but do not block the binding of fVIII to phospholipid. Most non-classical antibodies have inhibitor titers greater than 10,000 Bethesda units/mg IgG. To determine if non-classical antibodies are present in fVIII inhibitor patients, patient plasmas were tested in an ELISA for their ability to block the binding of representative antibodies from the different anti-human fVIII C2 antibody groups. Classical and non-classical monoclonal antibodies (MAbs) were biotinylated and serially diluted into either fVIII deficient plasma or patient inhibitor plasma and then added to microtiter wells coated with fVIII. The ability of patient plasma to block the binding of the murine MAbs to fVIII was determined. A total of 16 patient plasmas were assessed: 4 from patients with a C2 predominant response, 2 with a non-C2 predominant response, and 10 with unknown specificities. Three of the 4 patients with C2 predominant responses had non-classical anti-C2 antibodies, while the 2 with non-C2 predominant responses did not. In the unknown plasmas, 6 of 10 had evidence of non-classical antibodies. Figure 1 shows representative results of the effect of 3 patient plasmas on the binding of a biotinylated non-classical MAb to fVIII. Patient plasmas 1 and 2 blocked MAb binding while patient plasma 3 did not. This study indicates that the majority of patients with fVIII inhibitors have non-classical anti-C2 antibodies in their response to fVIII. Figure Figure

scholarly journals Some factor VIII inhibitor antibodies recognize a common epitope corresponding to C2 domain amino acids 2248 through 2312, which overlap a phospholipid-binding site

Blood ◽  
1995 ◽  
Vol 86 (5) ◽  
pp. 1811-1819 ◽  
Author(s):  
D Scandella ◽  
GE Gilbert ◽  
M Shima ◽  
H Nakai ◽  
C Eagleson ◽  
...  
Keyword(s):  
Amino Acids ◽  
Factor Viii ◽  
Binding Site ◽  
Light Chain ◽  
Intrinsic Factor ◽  
Factor Viii Inhibitor ◽  
C2 Domain ◽  
Amino Acid Residues ◽  
Fviii Inhibitor ◽  
Human Factor Viii

The finding that human factor VIII (fVIII) inhibitor antibodies with C2 domain epitopes interfere with the binding of fVIII to phosphatidylserine (PS) suggested that this is the mechanism by which they inactivate fVIII. We constructed a recombinant C2 domain polypeptide and demonstrated that it bound to all six human inhibitors with fVIII light chain specificity. Thus, some antibodies within the polyclonal anti-light chain population require only amino acids within C2 for binding. Recombinant C2 also partially or completely neutralized the inhibitor titer of these plasmas, demonstrating that anti-C2 antibodies inhibit fVIII activity. Immunoblotting of a series of C2 deletion polypeptides, expressed in Escherichia coli, with inhibitor plasmas showed that the epitopes for human inhibitors consist of a common core of amino acid residues 2248 through 2312 with differing extensions for individual inhibitors. The epitope of inhibitory monoclonal antibody (MoAb) ESH8 was localized to residues 2248 through 2285. Three human antibodies and anti-C2 MoAb NMC-VIII/5 bound to a synthetic peptide consisting of amino acids 2303 through 2332, a PS- binding site, but MoAb ESH8 did not. These antibodies also inhibited the binding of fVIII to synthetic phospholipid membranes of PS and phosphatidylcholine, confirming that the blocked epitopes contribute to membrane binding as well as binding to PS. In contrast, MoAb ESH8 did not inhibit binding. As the maximal function of activated fVIII in the intrinsic factor Xase complex requires its binding to a phospholipid membrane, we propose that fVIII inhibition by anti-C2 antibodies is related to the overlap of their epitopes with the PS-binding site. MoAb ESH8 did not inhibit fVIII binding to PS-containing membranes, suggesting the existence of a second mechanism of fVIII inhibition by anti-C2 antibodies.

scholarly journals Feiba Immuno: A Preparation with Factor Eight Inhibitor Bypassing Activity

1977 ◽  
Author(s):  
F. Elsinger
Keyword(s):  
Factor Viii ◽  
Factor Xa ◽  
Coagulation Factors ◽  
Active Principle ◽  
Factor Viii Inhibitor ◽  
Factor V ◽  
In Vitro Experiments ◽  
Factor X ◽  
Viii Inhibitor

FEIBA IMMUNO is a preparation in which a new activity is generated capable of bypassing factor VIII. The preparation which is used to treat patients with inhibitors (especially inhibitors to factor VIII) is standardized in FEIBA units, i.e. in terms of its in vitro capacity to shorten the activated PTT of a factor VIII inhibitor plasma.It could be concluded from different in vitro experiments that none of the classic’ activated coagulation factors is responsible for the factor VIII bypassing reaction; FEIB-activity seems to be correlated to a new complex of coagulation factors.To get an answer to the question which coagulation factors are essential for FEIB-activity, we tried to generate this activity from different deficient plasmas; from these experiments the following conclusions could be drawn:, the presence of at least factors VII, IX, and X is essential for the generation of the molecular species responsible for factor VIII as well as factor X bypassing activity, but factor V is not bypassed. This activity is not factor Xa itself. Factors VIII and V are not necessary for the generation of this active principle, but factor V is finally needed for its bypassing action.

Factor VIII Inhibitor Bypassing Activity (FEIBA) Reversal for Apixaban and Rivaroxaban in Patients With Acute Intracranial and Nonintracranial Hemorrhage

2021 ◽  
pp. 106002802110045
Author(s):  
Aleah R. Hunt ◽  
Shawn N. Coffeen ◽  
Dane L. Shiltz ◽  
Calvin Ice ◽  
Jessi Parker
Keyword(s):  
Factor Viii ◽  
Controlled Trial ◽  
Safety Data ◽  
Case Series ◽  
Factor Xa ◽  
Factor Viii Inhibitor ◽  
Post Discharge ◽  
Viii Inhibitor ◽  
Fxa Inhibitor ◽  
Record Review

Background: The clinical use of factor VIII inhibitor bypassing activity (FEIBA) for factor Xa (FXa) inhibitor reversal is derived from small studies with notable variation in patient eligibility for use, dosage regimens, concurrent supportive care, and outcome measures. Consequently, additional effectiveness and safety data are warranted to expand the literature evaluating FEIBA for FXa inhibitor reversal. Objective: This study sought to determine the incidence of observed effective hemostasis within 24 hours of post-FEIBA® administration as well as in-hospital and 30-day post-discharge incidences of thromboembolic event (TEE) and mortality between apixaban and rivaroxaban in the intracranial hemorrhage (ICH) and non-ICH populations. Methods: This case series evaluated patients between January 1, 2014 through July 1, 2019 who received at least one FEIBA® dose for apixaban or rivaroxaban reversal secondary to acute ICH or non-ICH. Patient demographics, FEIBA® dosages, adjunct treatments, effectiveness, and safety outcomes were retrospectively collected from electronic medical record review. Modified hemostasis outcomes, adapted from criteria previously published by Sarode et al., TEE, and mortality between apixaban and rivaroxaban in the ICH and non-ICH populations were evaluated. Results: Among the 104 patients evaluated, 62 received apixaban and 42 rivaroxaban. Thirty apixaban and 25 rivaroxaban users experienced ICH, whereas 32 apixaban and 17 rivaroxaban users experienced non-ICH. Among the combined ICH and non-ICH populations, effective hemostasis occurred in 89%, TEE in 8%, and mortality in 13%. No statistically significant differences were observed within ICH and non-ICH populations receiving apixaban or rivaroxaban regarding effective hemostasis, TEE, or mortality. Conclusion and Relevance: The combined ICH and non-ICH overall rates of effective hemostasis, TEE, and mortality were comparable to preexisting studies of FEIBA for factor Xa inhibitor reversal. The limitations inherent to the study design warrant a randomized controlled trial with an active comparator to confirm these observations.

scholarly journals Marginal zone B cells are critical to factor VIII inhibitor formation in mice with hemophilia A

Blood ◽  
2017 ◽  
Vol 130 (23) ◽  
pp. 2559-2568 ◽  
Author(s):  
Patricia E. Zerra ◽  
Courtney Cox ◽  
W. Hunter Baldwin ◽  
Seema R. Patel ◽  
Connie M. Arthur ◽  
...  
Keyword(s):  
B Cells ◽  
Factor Viii ◽  
Marginal Zone ◽  
Hemophilia A ◽  
Factor Viii Inhibitor ◽  
Marginal Zone B Cells ◽  
Inhibitor Development ◽  
Fviii Inhibitor ◽  
Key Points ◽  
Viii Inhibitor

Key Points FVIII colocalizes with MZ B cells following infusion into hemophilia A mice. Depletion of MZ B cells prevents FVIII inhibitor development in hemophilia A mice.

Spontaneous disappearance of high titre factor VIII inhibitor 15 years after unsuccessful ITI

2009 ◽  
Vol 29 (02) ◽  
pp. 149-150
Author(s):  
K. Thom ◽  
J. Falger ◽  
I. Pabinger ◽  
C. Male
Keyword(s):  
Factor Viii ◽  
Tolerance Induction ◽  
High Titre ◽  
Bleeding Complications ◽  
Factor Viii Inhibitor ◽  
Fviii Inhibitor ◽  
Spontaneous Disappearance ◽  
Viii Inhibitor ◽  
Bypassing Agents ◽  
High Doses

SummaryThe most serious complication of haemophilia A is development of a high-titre factor VIII (FVIII) inhibitor which renders the patient unresponsive to FVIII replacement. Bleeding complications can only be controlled using FVIII-inhibitor bypassing agents but their effect is less certain. The ultimate goal is to eliminate the inhibitor by immune tolerance induction therapy (ITI) using daily high doses of FVIII. The success rate of ITI using various protocols is between 56 and 79% (1, 2). If ITI is unsuccessful, the inhibitor usually persists throughout life.We report on a patient with a high titre FVIII inhibitor that persisted after ITI but spontaneously disappeared 15 years later.

ANALYSIS OF HUMAN FACTOR VIII INHIBITOR EPITOPES TO FACTOR VIII POLYPEPTIDES BY IMMUNOBLOTTING

1987 ◽  
Author(s):  
A Yoshioka ◽  
M Shima ◽  
I Tanaka ◽  
T Fujiwara ◽  
H Nakai ◽  
...  
Keyword(s):  
Autoimmune Disease ◽  
Factor Viii ◽  
Column Chromatography ◽  
Human Factor ◽  
Hemophilia A ◽  
Blue Staining ◽  
Factor Viii Inhibitor ◽  
Human Factor Viii ◽  
Viii Inhibitor ◽  
Group 3

In order to clarify human factor VIII inhibitor epitopes to factor VIII (F. VIII), we analyzed the inhibitor IgG developed in the patients with hemophilia A and autoimmune disease using immunoblotting of purified F. VIII and thrombin-degraded F. VIII. IgG fractions were obtained from 6 cases of severe hemophilia A and one autoimmune disease. The titer of the inhibitor plasma ranged from 50 to 3,000 Bethesda units/ml. Purification of F. VIII from commercial F. VIII concentrate was performed by immunoadsorbent column chromatography using anti-von Willebrand factor monoclonal antibody and anti-fibrinogen, anti-fibronectin and anti-IgM goat antibodies and subsequently by Aminohexyl Sepharose column chromatography essentially according to the method of Fulcher et al.. The specific activity of the purified F. VIII was 2,700 units/mg. On sodium-dodecylsulfate (SDS) 5 to 10% gradient polyacrylamide gel electrophoresis (PAGE), 80 kDa of a main fragment and a series of 90 to 210 kDa fragments were visualyzed by Coomassie blue staining. Immunoblotting of 5-10 ug of each of unreduced purified F. VIII and thrombin-degraded F. VIII. followed by reaction with inhibitor IgG samples, monoclonal antihuman IgG-3 and IgG-4 antibodies and radiolabeled rabbit antimouse IgG.All inhibitor IgG samples reacted with both purified F. VIII and thrombin-degraded F. VIII. The pattern of reactivity of inhibitor antibodies was divided into three groups; 1) inhibitor IgG which reacted with 80 and 70 kDa derived from carboxy-terminus of the F. VIII molecule, 2) inhibitor IgG which reacted with 90 to 210 kDa and 54 and/or 44 kDa derived from amino-terminus of the F. VIII, and 3) inhibitor IgG which reacted with both of N- and C-terminus of the F. VIII. One inhibitor IgG belonged to group 3 strongly reacted with a series of higher molecular polypeptides of F. VIII ranged from 180 .to 210 kDa. One autoantibody IgG from the patient with autoimmune disease was also belonged to group 3. There was no relationship between the titer and the pattern of reactivity of each inhibitor plasma. In summary, there is a heterogeneity of F. VIII inhibitor epitopes to F. VIII molecules.

scholarly journals Experimental Studies on Factor VIII Inhibitor Bypassing Activity

1977 ◽  
Author(s):  
H. Vinazzer
Keyword(s):  
Factor Viii ◽  
Calcium Chloride ◽  
Experimental Studies ◽  
Factor Xa ◽  
Factor Viii Inhibitor ◽  
Factor V ◽  
Factor X ◽  
Tissue Thromboplastin ◽  
Viii Inhibitor ◽  
Thrombin Formation

The exact action of factor VIII inhibitor bypassing activity (FEIBA) is still unclear. For this reason, a series of experimental studies was carried out. Procoagulant activities were examined by standard one-stage methods while factor Xa and thrombin were measured by chromogenic substrates. Activities of factors II, VII, IX, and X were similar to PPSB fractions. In addition, low factor V activity and a phospholipid were detected. No activated factor X was present in FEIBA but there was a trace amount of 2.1 NIH units of thrombin per 100 FEIBA units. On addition of calcium chloride slow thrombin formation could be observed which however, reached 1100 NIH units of thrombin per 100 FEIBA units within an incubation time of 10 min. The velocity of thrombin formation was greatly enhanced by addition of a PTT reagent and of thromboplastin respectively. Factor Xa on the other hand, was neither formed after addition of calcium chloride nor by a PTT reagent. Tissue thromboplastin however, activated Xa from FEIBA in the same manner as a PTT reagent plus barium sulfate plasma. From these results, the conclusion could be drawn that thrombin could readily be made available from FEIBA while activation of Xa either needed the complete endogenous pathway or the presence of tissue thromboplastin. The procoagulant activity of FEIBA therefore, could be attributed to direct thrombin formation. By this process, an activation of the clotting mechanism in plasmas deficient in endogenous coagulation factors, and a complete independence from the presence or absence of a specific antibody could be explained.

Anti-CD3 prevents factor VIII inhibitor development in hemophilia A mice by a regulatory CD4+CD25+-dependent mechanism and by shifting cytokine production to favor a Th1 response

Blood ◽  
2009 ◽  
Vol 113 (1) ◽  
pp. 193-203 ◽  
Author(s):  
Braden Waters ◽  
Mohammad Qadura ◽  
Erin Burnett ◽  
Rouzbeh Chegeni ◽  
Andrea Labelle ◽  
...  
Keyword(s):  
Factor Viii ◽  
Cytokine Production ◽  
Hemophilia A ◽  
Phenotypic Characterization ◽  
Factor Viii Inhibitor ◽  
Related Complication ◽  
Fviii Inhibitor ◽  
Short Course ◽  
Viii Inhibitor

Abstract Non–Fc-receptor binding anti-CD3 Ab therapy, in the setting of several different autoimmune disorders, can induce antigen-specific and long-lasting immunologic tolerance. Because factor VIII (FVIII) inhibitor formation is the most serious treatment-related complication for hemophilia A patients, we tested the efficacy of anti-CD3 to prevent FVIII inhibitor formation in hemophilia A BALB/c and C57BL/6 mice. A short course of low-dose anti-CD3 significantly increased expression of CD25 and the proportion of CD4+CD25+ regulatory T cells in the spleen and potently prevented the production of inhibitory and non-neutralizing anti-FVIII antibodies in both strains of mouse. Depleting the CD4+CD25+ cells during anti-CD3 therapy completely ablated tolerance to FVIII. Further phenotypic characterization of regulatory cells in tolerant mice showed a consistently higher number of CD4+GITR+ and CD4+FoxP3+ cells in both strains of mice. In addition, in tolerant C57BL/6 mice we observed an increase in CD4+CD25+CTLA-4+ and CD4+CD25+mTGF-β1+ cells. Finally, in vitro cytokine profiling demonstrated that splenocytes from tolerant BALB/c and C57BL/6 were polarized toward a Th1-immune response. Taken together, these findings indicate that anti-CD3 induces tolerance to FVIII and that the mechanism(s) regulating this response almost certainly occurs through the generation of several distinct regulatory T-cell lineages and by influencing cytokine production and profile.

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