Factor VIII inhibitors. Etiology, characterization, natural history, and management

Management of Odontogenic Fascial Space Infection in Hemophilia Patients: A Proposed Protocol

Purpose

The purpose of this study was to suggest a protocol for the management of odontogenic space infections in patients with hemophilia which is often incompletely addressed by clinicians because of the fear of excessive bleeding leading to prolonged morbidity.

Methods and Results

Six diagnosed cases of hemophilia (four cases of hemophilia A and two cases of hemophilia B) with odontogenic fascial space infection were included in the study. Apart from routine investigations, assessments were also done to identify inhibitors to factor VIII/IX. Factor VIII/IX was replaced along with infusion of factor eight inhibitor bypass activity (FEIBA) one hour before incision and drainage. All the cases were treated by incision and drainage along with removal of foci under local anesthesia. The postoperative outcome was uneventful in all cases except one in which postoperative bleeding was noted from the extraction site on the third day which was again managed following the designed protocol.

Conclusion

Maintaining good oral hygiene and seeking early dental care are of prime importance in patients with hemophilia to avoid invasive procedures. However, if odontogenic infection develops in these patients, performing timely incision and drainage using our protocol will minimize the complications and give successful outcome.

"Antihemophilic factor is not the only answer for all factor VIII deficiencies." Case report of odontogenic infection in a patient with hemophilia A, complicated by factor VIII inhibitors, and managed by transfusion of antihemophilic factor and factor VIII inhibitor bypass activity

Dental extraction in hemophiliacs with acquired inhibitors is always a risky procedure, which often presents a lot of problems associated with bleeding. A known case of hemophilia A complicated with factor VIII inhibitors and having odontogenic infection was successfully managed by transfusion of factor VIII inhibitor bypass activity (FEIBA) and antihemophilic factor. Past medical history was significant for multiple factor VIII transfusions. Bethesda assay done to identify inhibitors revealed low titer factor VIII inhibitors. Extraction of the involved tooth was done after transfusion of FEIBA with low-dose protocols. Minimal bleeding was noted after extraction which was controlled by local measures. FEIBA was proven to be highly effective, and no side effects of the product were observed.

Antihuman factor VIII C2 domain antibodies in hemophilia A mice recognize a functionally complex continuous spectrum of epitopes dominated by inhibitors of factor VIII activation

The diversity of factor VIII (fVIII) C2 domain antibody epitopes was investigated by competition enzyme-linked immunosorbent assay (ELISA) using a panel of 56 antibodies. The overlap patterns produced 5 groups of monoclonal antibodies (MAbs), designated A, AB, B, BC, and C, and yielded a set of 18 distinct epitopes. Group-specific loss of antigenicity was associated with mutations at the Met2199/Phe2200 phospholipid binding beta-hairpin (group AB MAbs) and at Lys2227 (group BC MAbs), which allowed orientation of the epitope structure as a continuum that covers one face of the C2 beta-sandwich. MAbs from groups A, AB, and B inhibit the binding of fVIIIa to phospholipid membranes. Group BC was the most common group and displayed the highest specific fVIII inhibitor activities. MAbs in this group are type II inhibitors that inhibit the activation of fVIII by either thrombin or factor Xa and poorly inhibit the binding of fVIII to phospholipid membranes or von Willebrand factor (VWF). Group BC MAbs are epitopically and mechanistically distinct from the extensively studied group C MAb, ESH8. These results reveal the structural and functional complexity of the anti-C2 domain antibody response and indicate that interference with fVIII activation is a major attribute of the inhibitor landscape.

Application of current knowledge to the management of bleeding events during immune tolerance induction

The development of inhibitors to factor VIII is the most serious adverse event associated with the treatment of haemophilia A, predisposing patients to uncontrollable haemorrhage, disability and premature death. Eradication of inhibitors via immune tolerance induction (ITI) is effective in the majority of patients, but may require months to years to achieve success. In the interim, the treatment and prevention of acute bleeding episodes are primary foci of care. Regrettably, there is a paucity of information regarding management of bleeding episodes in inhibitor patients undergoing tolerization. Until specific data from ongoing clinical trials are available to provide more guidance in this patient group, it is reasonable and useful to rely on the broader base of medical literature pertaining to patients not being tolerized to deduce strategies for controlling acute and perioperative bleeding episodes in inhibitor patients during ITI.

Prevention of bleeds in hemophilia patients with inhibitors: emerging data and clinical direction

In patients with hemophilia, the development of high-responding inhibitors to factor VIII prevents adequate replacement therapy and results in increased risk of serious bleeding episodes, poor control of joint bleeding, and progressive, debilitating joint disease. Immune tolerance therapy can eradicate inhibitors, but it is not uniformly successful. Emerging data suggest that prophylaxis using activated prothrombin complex concentrates may be effective and safe in reducing the incidence of joint bleeding during immune tolerance therapy and for patients in whom immune tolerance induction fails. However, only controlled clinical trials will ultimately demonstrate whether prophylaxis can prevent joint bleeding and damage, and improve quality of life in patients with inhibitors.

Effectiveness of factor VIII infusions in haemophilia A patients with high responding inhibitors

We report here the efficacy of factor VIII (FVIII) infusions in two haemophiliacs with inhibitors using clot waveform analysis on the MDA II system, which was possible to detect very low levels of FVIII activity < 1.0 U dL(-1). In the presence of type 1 inhibitors at the level of 6.2 (patient 1) and 14.4 (patient 2) Bethesda Units mL(-1), 3.2 and 6.5 U dL(-1) of FVIII:C remained 30 min after the infusion of FVIII (100 U kg(-1)), respectively. Moreover, 0.9 U dL(-1) of FVIII:C remained 24 h after infusion in patient 2. In both cases, these changes were reflected by qualitative improvement in the aPTT clot waveform and quantitative changes in the minimum value of the second derivative of the aPTT waveform (Min2) that reflects clot acceleration. These results suggest that FVIII infusion may be continued with clinical benefit in some haemophiliacs with high responding inhibitors. Furthermore, the haemostatic response may be monitored accurately and efficiently by clot waveform analysis.

State of care for hemophilia in pediatric patients

On demand treatment of bleeding episodes is still the main approach to hemophilia care of patients of any age. Prompt infusion of coagulation factor concentrate in the home setting allows treatment of hemorrhages at early onset, reducing the incidence of complications and improving the quality of life. Nevertheless, the technological evolution and progressive improvement in the safety of therapeutic products have changed the management of the disease, particularly in children. The current availability of safer concentrates has drastically reduced the risk of transmission of blood-borne infections. Innovative approaches, such as early primary prophylaxis and immune tolerance induction, have become feasible and their introduction represents a major advance in the achievement of the main therapeutic goals: control of the bleeding diathesis and elimination of inhibitors. Prophylactic regimens have been shown to be effective in preventing the occurrence not only of joint bleeding but also of arthropathy when started early in children with severe hemophilia. Inhibitor development still represents the main complication of hemophilia treatment, making concentrate administration ineffective. Immune tolerance induction by daily infusion of coagulation factor concentrate was shown to eradicate the inhibitors in 63 to 83% of patients. These intensive treatment regimens are administered at home to very young children and create the problem of adequate venous access. Subcutaneous venous ports have been used in patients with hemophilia if peripheral veins could not be frequently accessed; however, the risk of infection is an important limit to their use.

Development of spontaneous factor VIII inhibitor in association with acute graft-versus-host disease

A 57-year-old female with recurrent AML underwent a T cell-depleted (TCD) bone marrow (BM) plus TCD and CD34-selected peripheral blood stem cell (PBSC) transplant. Eleven weeks post transplantation, the patient developed acute graft-versus-host disease (GVHD) manifested by rash and elevated liver enzymes. Concurrently, the patient presented with a bleeding diathesis and a left forearm hematoma due to the development of a spontaneous factor VIII inhibitor. She was treated with human recombinant factor VIII and intravenous methylprednisolone. Subsequently she was managed with a prednisone taper leading to resolution of the GVHD, as well as the spontaneous factor VIII inhibitor. Bone marrow transplant-related spontaneous factor VIII inhibitor has previously been reported in association with one patient with chronic GVHD. To our knowledge this is the first report of spontaneous factor VIII inhibitor associated with acute GVHD.

How I treat patients with von Willebrand disease

Von Willebrand disease (vWD) is a frequent inherited disorder of hemostasis that affects both sexes. Two abnormalities are characteristic of the disease, which is caused by a deficiency or a defect in the multimeric glycoprotein called von Willebrand factor: low platelet adhesion to injured blood vessels and defective intrinsic coagulation owing to low plasma levels of factor VIII. There are 2 main options available for the treatment of spontaneous bleeding episodes and for bleeding prophylaxis: desmopressin and transfusional therapy with plasma products. Desmopressin is the treatment of choice for most patients with type 1 vWD, who account for approximately 70% to 80% of cases. This nontransfusional hemostatic agent raises endogenous factor VIII and von Willebrand factor 3 to 5 times and thereby corrects both the intrinsic coagulation and the primary hemostasis defects. In patients with the more severe type 3 and in most patients with type 2 disease, desmopressin is ineffective or is contraindicated and it is usually necessary to resort to plasma concentrates containing both factor VIII and von Willebrand factor. Concentrates treated with virucidal methods should be preferred to cryoprecipitate because they are equally effective and are perceived as safer. (Blood. 2001;97:1915-1919)

Acquired haemophilia

Acquired haemophilia is a rare but life-threatening acquired bleeding diathesis caused by autoimmune depletion of factor VIII. This occurs most frequently in elderly patients who lack disease associations. Acquired haemophilia may also arise in association with SLE rheumatoid arthritis, Sjögren's syndrome, other autoimmune conditions, lymphoproliferative malignancy, pregnancy and as a drug reaction. Acquired haemophilia has an equal sex distribution. The aims of treatment are to eliminate the inhibitor by immunosuppression and to treat the bleeding, which is the most common cause of death in patients with acquired haemophilia. The inhibitor is abolished in up to 70% of patients using prednisolone and cyclophosphamide, although other immunosuppressive regimens may also be used. These include azathioprine, vincristine and other cytotoxic agents, high-dose immunoglobulin and cyclosporin A. Bleeding may be controlled using porcine factor VIII or recombinant factor VIIa, although human factor VIII and prothrombin complex concentrates also have a limited role as haemostatic agents in this condition.

Treatment of acquired factor VIII inhibitor using intravenous immunoglobulin in two patients with systemic lupus erythematosus

Acquired inhibitors of factor VIII have rarely been reported in the presence of systemic lupus erythematosus (SLE). Treatment is usually corticosteroids, with or without immunosuppressive agents such as cyclophosphamide or azathioprine. We report here case histories of 2 patients, one with documented SLE, the other with a forme fruste of SLE. Both patients had inadequate responses to corticosteroids and immunosuppressive agents. Both responded to intravenous immunoglobulin, with a decrease in their titers of factor VIII inhibitor and significantly decreased frequency of bleeding episodes despite persistent low-level inhibitor titers. Better control of their SLE symptoms and findings was also observed. Previously reported treatments of acquired factor VIII inhibitors in SLE are discussed.

Inhibitors in congenital haemophilia

Inhibitor formation is a serious complication, occurring in 24-52% of patients with haemophilia A and in 1.5-3% of patients with haemophilia B. Low-titre inhibitors can easily be overcome and do not represent a treatment challenge. They are treated with increased doses of factor concentrate. However, high-titre inhibitors may still cause death from haemorrhage in this population. Optimal treatment of acute, life-threatening haemorrhage in patients with factor VIII inhibitors includes either porcine factor VIII or human factor VIII in high doses since, with both modalities, circulating factor levels are achievable. If the inhibitor titres are too high, plasmapheresis may be warranted. For routine joint bleeds, PCC or aPCC can be administered at home with variable success. For patients with factor IX inhibitors treatment options are more limited. If the haemorrhage is life-threatening, plasmapheresis should be done to decrease the inhibitor and high doses of pure factor IX administered either by continuous infusion or bolus. Attainment of levels of > 20% should be attempted. New clinical options, such as rFVIIa, may emerge. For both groups of patients, IT should be started as soon as the inhibitor is discovered and its behaviour characterized. Unfortunately, no standard regimen for IT exists and the treater will have to choose whichever schedule he/she feels is the most appropriate.

Response to botulinum toxin F in seronegative botulinum toxin A--resistant patients

Botulinum toxin type A (btx A) injections are the most effective treatment for most patients with focal dystonia. Some patients who improve after btx A injections and later lose response have serologic evidence of antibodies to btx A with the mouse neutralization assay (seropositive patients). Another group of patients who lose response to btx A do not have detectable antibodies (seronegative patients). Seropositive patients may improve after injections of botulinum toxin type F (btx F), an alternative serotype of botulinum toxin. We treated nine seronegative resistant patients with btx F. None of these patients had muscle atrophy after injection with btx A. Five of the nine had improvement after btx F injection that was sustained for at least three consecutive btx F injections. This observation is consistent with the hypothesis that btx resistance in seronegative patients is caused by undetected antibodies to btx A. If this be the case, then there may be techniques for preventing or reversing btx resistance, as in the case of resistance of factor VIII in the treatment of hemophilia A.

Spontaneous factor VIII inhibitor occurring in association with chronic graft-versus-host disease

The development of spontaneously acquired Factor VIII inhibitors is rare and may lead to serious hemorrhagic sequelae. We report here the case of a patient who acquired a Factor VIII inhibitor two years after an allogeneic bone marrow transplant for CML. This occurred in association with a flare of chronic graft versus host disease (GVDH). He responded to corticosteroid therapy. A review of autoimmune phenomena associated with chronic GVDH and the treatment of Factor VIII inhibitors is discussed.

DDAVP in acquired hemophilia A: case report and review of the literature

One patient with an acquired factor VIII inhibitor is reported in which an acute lower intestinal hemorrhage was successfully managed using Desmopressin (DDAVP). The patient initially had a factor VIII level of 10% with a inhibitor titer of 1.9 Bethesda units. Following administration of DDAVP the factor VIII level rose to 86% and there was a decrease in the number and volume of bloody stools. The inhibitor disappeared following treatment with corticosteroids, however the patient ultimately expired due to complications of ischemic colitis. This case and 21 previously reported cases of acquired hemophilia treated with DDAVP are reviewed. The data support a role for DDAVP in the treatment of non life threatening hemorrhage in patients with acquired hemophilia and low titer factor VIII inhibitors (< 5 Bethesda units or factor VIII > or = 5%).

Recombinant factor VIII for the treatment of previously untreated patients with hemophilia A. Safety, efficacy, and development of inhibitors. Kogenate Previously Untreated Patient Study Group

BACKGROUND

Although methods of viral attenuation in plasma-derived clotting-factor concentrates have improved, there is still a possibility that such concentrates may transmit certain blood-borne viruses. For this reason, the use of recombinant DNA-derived factor VIII (which is virus-free) to treat hemophilia A has generated considerable interest.

METHODS

We conducted a multicenter trial in previously untreated children with hemophilia A. They received recombinant factor VIII for all treatment or for prophylaxis and were evaluated at their respective clinics at intervals of no more than three months.

RESULTS

Between January 1, 1989, and July 1, 1992, 95 patients who could be evaluated received recombinant factor VIII. By September 1, 1992, they had received the concentrate exclusively for 2.4 months to 3.5 years (median, 1.5 years). All responded well, with no treatment failures. A total of 3315 infusions were administered; there were three reports of minor adverse reactions. Inhibitor antibodies to factor VIII developed in 16 of 81 patients tested for them, after a median of nine days of exposure to factor VIII treatment. Inhibitor titers were or became low in 9 of the 16 patients despite continued episodic treatment with the concentrate. Inhibitors disappeared completely in 4 patients and remained at a low level (< 10 Bethesda units) in 5 patients receiving episodic treatment.

CONCLUSIONS

Transient or low levels of inhibitor, as observed in this study, may represent part of the natural history of hemophilia in infants. In view of the transient nature and lower concentration of the inhibitors detected and the generally satisfactory response to treatment, the benefits of recombinant factor VIII for the treatment of hemophilia seem to outweigh the risks.