OBJECTIVETo develop a monoclonal antibody (mAb) directed to FVIII C2 domain and investigate its effect on FVIII activity.

METHODSFVIII C2 protein was expressed in E. coli and purified. A murine antihuman FVIII C2 domain mAb SZ-132 was developed by standard hybridoma technology and characterized. In coagulation assays, different concentrations of SZ-132 were incubated with freshly collected pooled human plasma and the residual activity of FVIII and activated partial thromboplastin time (APTT) were determined. The effects of SZ-132 on rhFVIII binding to purified human vWF, phosphatidylserine (PS) and platelets were assessed by enzyme linked immunosorbent assays (ELISA).

RESULTSSZ-132 could inhibit FVIII procoagulant activity in a dose-dependent manner within the concentrations of 0-25 microg/ml and the FVIII activity was completely inhibited on above 25 microg/ml. It could also prevent rhFVIII from binding to vWF, PS and platelets.

CONCLUSIONSSZ-132 is a neutralizing mAb against FVIII C2 domain and can inhibit FVIII procoagulant activity by preventing FVIII from binding to vWF and PS.

Animals ; Antibodies, Monoclonal ; biosynthesis ; immunology ; Antibodies, Neutralizing ; biosynthesis ; immunology ; Factor VIII ; immunology ; metabolism ; Humans ; Male ; Mice ; Mice, Inbred BALB C

OBJECTIVETo explore the immune tolerance induction (ITI) in a severe hemophilia A patient with inhibitor, and to improve the therapeutic efficacy for patient.

METHODSThe FVIII:C was assayed by one-stage method and FVIII antibody by Bethesda method. Mutation screening of FVIII gene intron 22 inversion was performed using LD-PCR.

RESULTSFVIII gene intron 22 inversion was detected in this patient. Clinical tolerance to FVIII was successfully induced after administration of the ITI regimen combined with immunosuppression. A fall of inhibitor titer from 8 BU to 0 BU after treatment for 3 months, and in vivo FVIII recovery (> 66%) was normalized. The patient had no bleeding episode in the following 6 months.

CONCLUSIONThis is the first case report on successful immune tolerance induction therapy in Chinese hemophilia A patient. ITI is the most effective therapy for hemophilia A with inhibitor.

Autoantibodies ; immunology ; Factor VIII ; genetics ; Hemophilia A ; genetics ; Humans ; Immune Tolerance ; drug effects ; Immunosuppression

Acquired hemophilia is a rare disorder caused by autoantibodies to factor VIII (FVIII) (also referred to as factor VIII inhibitors or anti-FVIII) and may be associated with pregnancy, underlying malignancy, or autoimmune disorders. A 33-month-old girl who presented with hematochezia and ecchymotic skin lesions was diagnosed with Mycoplasma pneumoniae pneumonia by serology and polymerase chain reaction. Hematologic studies showed a prolonged activated partial thromboplastin time (aPTT), partially corrected mixing test for aPTT, reduced levels of FVIII, and the presence of antibodies against FVIII. She was treated conservatively with prednisone and intravenous immunoglobulin (IVIG) without FVIII transfusion and recovered without sequelae. This report provides the first description of acquired hemophilia due to anti-FVIII in association with M. pneumoniae in Korea. We discuss this case in the context of the current literature on acquired hemophilia in children.
Autoantibodies/blood ; Child, Preschool ; Factor VIII/immunology ; Female ; Hemophilia A/*etiology ; Humans ; Partial Thromboplastin Time ; Pneumonia, Mycoplasma/*complications/immunology ; Time Factors

OBJECTIVETo identify the clinical and laboratory diagnosis of a bullous pemphigoid patient with acquired hemophilia A (AH-A). To identify FVIII binding epitope and IgG subclass of the FVIII inhibitor, and explore the molecular mechanism for AH-A pathogenesis.

METHODSPlasma FVIII activity( FVIII: C) was determined by one-stage assay, the titre of FYIII inhibitor by Bethesda Unit (BU). IgG purification of patient plasma or normal pooled plasma was finished by protein A-agarose column chromatography. Activated partial thromboplastin time (APTT) was assayed for uncovering FVIII inhibitor effect on FVIII in vivo. Combined Western blot analysis by anti-IgG1, IgG2, IgG3 and IgG4 antibodies was used to determine the relative concentration of patient' s IgG subclass. IgG subclass concentrations were quantified by nephelometric method. Solid-phase binding assay of FVIII and FVIII inhibitor, combined with Western blot was used to recognize the binding epitope at which the FVIII inhibitor bound to FVIII.

RESULTS(1) Plasma APTT value of patient was prolonged evidently and could not be corrected by normal pooled plasma. Patient's FVIII: C was < 1.5%. The titre of FVIII inhibitor in patient plasma was 147.8 BU. (2) The purified patient IgG was able to inhibit FVIII: C of normal pooled plasma significantly with a dose dependent manner, and the patient plasma could prolong rabbit plasma APTT markedly with a time dependent manner. (3) The FVIII inhibitor was predominantly then of IgG4 subtype with a minority IgG1, and the concentration of IgG4 and IgG1 in the patient was higher than that in normal. The FVIII inhibitor reacted with FVIII 44 x 10(3) fragment epitope.

CONCLUSIONSThe inhibiting effect of FVIII inhibitors on FVIII: C in the bullous pemphigoid patient with AH-A is determined and the IgG subclass of the FVIII inhibitor is identified. A binding epitope for the FVIII inhibitor is a FVIII 44 x 10(3) fragment. The results provides evidence for understanding the pathogenesis of AH-A.

Animals ; Epitopes ; Factor VIII ; antagonists & inhibitors ; immunology ; Female ; Hemophilia A ; complications ; etiology ; immunology ; Humans ; Immunoglobulin G ; blood ; Middle Aged ; Pemphigoid, Bullous ; complications ; immunology ; Rabbits

To determine laboratory evidence suggesting immunological abnormalities in persons with hemophilia, we evaluated the immunological status of 75 Korean hemophiliacs, seronegative for human immunodeficiency virus (HIV) antibodies, who have been treated only with Korean factor VIII concentrates. From this study, it was shown that Korean hemophiliacs had decreased CD4 levels, increased CD8 levels, and decreased CD4:CD8 ratios. Diminished lymphocyte response to the mitogens, phytohemagglutinin and concanavalin A, and decreased natural killer cell activity were observed in the hemophiliacs. In addition, production of interleukin-II in the hemophiliacs was lower than in the healthy controls. The percentage of B lymphocytes was significantly reduced but the serum levels of immunoglobulin (Ig) G were elevated. However, the serum Ig A and Ig M levels were normal. This study demonstrated a high frequency of immunological abnormalities in HIV antibody negative Korean hemophiliacs treated only with domestic factor VIII concentrates.
Adolescent ; Adult ; Child ; Factor VIII/therapeutic use ; HIV Seropositivity/immunology ; Hemophilia A/drug therapy/*immunology ; Human ; Korea ; Lymphocyte Activation ; Lymphocytes/immunology ; Male ; Middle Age ; Support, Non-U.S. Gov't

Epithelioid hemangioendothelioma is a rare vascular origin tumor which usually occurs in soft tissues, liver, and lung. It usually affects adult women and presents as multiple hepatic nodules with mainly peripheral distribution. It is difficult to diagnose and treat because of non-specific clinical manifestations and findings on the imaging study. Moreover, pathological misdiagnosis is common. We report a case of this rare tumor that was detected incidentally. Final diagnosis was based on histological evidence. A 52-years old man suffered from right upper quadrant abdominal pain for 3 months, and was initially misdiagnosed as a metastatic carcinoma. Physical examination revealed superior cervical lymphadenopathy with mild hepatomegaly. Finally, hepatic epithelioid hemangioendothelioma was diagnosed on the basis of positive immunohistochemical staining for factor VIII, CD34, and VEGF. Our case highlights the importance of a histological diagnosis to avoid misdiagnosis.
Antigens, CD34/analysis/immunology ; Carcinoma/secondary ; Diagnosis, Differential ; Factor VIII/analysis/immunology ; Hemangioendothelioma, Epithelioid/*diagnosis/pathology ; Humans ; Immunohistochemistry ; Liver Neoplasms/*diagnosis/pathology ; Male ; Middle Aged ; Positron-Emission Tomography

This study was purposed to investigate the diagnosis, typing and influencing factors of the antibody (inhibitor) to coagulation factors in hemophilia. 500 hemophilia patients were enrolled in this study. The activities of coagulation factor FVIII and FIX were tested by one stage assay. The antibodies of FVIII and FIX were detected by Bethesda assay. All data were analyzed by statistical soft SPSS 10.0. The results indicated that there were 411 cases of hemophilia A, out of which 151 cases (30.2%) showed FVIII antibody positive, the titer was 3.50 ± 2.84 Bu/ml; there were 79 cases of hemophilia B, out of which 18 cases (3.6%) showed FIX antibody positive, the titer was 2.92 ± 2.19 Bu/ml. The other 10 cases were acquired autogeneic hemophilia (2.0%). The antibody was divided into three types: high-response (3 cases), intermediate-response (47 cases), and low-response (119 cases). Among the 169 cases with antibody positive, 157 cases (92.9%) were younger than 30 years old; among 151 (89.35%) cases of hemophilia A; 138 cases (81.66%) were moderate or severe hemophilia; 166 case (98.22%) showed intermediate or low-response antibody. There were 158 cases with allogeneic antibody positive, all of which received blood transfusion. It is concluded that the moderate and low responsive antibodies are the dominant in hemophilia patients, the age of patients and transfusion frequency of blood preparation are the influencing factors. The results of this study provide the basis for the hemophilia diagnosis, antibody typing and evaluation of factors influencing hemophilia, and also suggest that the repeated transfusion of blood preparation may influence the production of antibodies.
Adolescent ; Adult ; Aged ; Autoantibodies ; blood ; Child ; Child, Preschool ; Factor VIII ; immunology ; Female ; Hemophilia A ; blood ; diagnosis ; immunology ; Humans ; Infant ; Male ; Middle Aged ; Young Adult

INTRODUCTIONWe report a successful case of immune tolerance to factor VIII (FVIII) inhibitor after a major operation. An attempt was made to induce immune tolerance with inhibitor in a haemophilia A patient, who was required to undergo an above-knee amputation. We opted to give high-dose FVIII infusion with no immunosuppression.

OUTCOMEThe highest preoperative FVIII inhibitor level was 5 BU and the peak postoperative FVIII inhibitor level was 1.5 BU demonstrated on Day 9 post operation. High-dose FVIII support was provided during the perioperative period and continued with a low maintenance dose to achieve a FVIII level of 30% to 40%. The requirement of high-dose FVIII lasted from day 6 to 23 post operation and this was tailed down to a maintenance dose over the next 37 days. There were only 2 episodes of mild oozing from the wound at around Day 9, which coincided with the peak postoperative FVIII inhibitor level. Both bleeding episodes were arrested adequately by administering a single dose of FEIBA during each episode. Immune tolerance was demonstrated after around 3 months and a follow-up period of 233 days showed no recurrence of FVIII inhibitor with the normalisation of FVIII half-life study.

CONCLUSIONAfter immune tolerance, the patient suffered fewer episodes of joint haemorrhage and required a lower amount of FVIII infusion as well. The cost may be high initially but the longterm cost-effectiveness has to be carefully evaluated.

Adult ; Amputation ; Coagulants ; administration & dosage ; immunology ; Factor VIII ; administration & dosage ; immunology ; Hemophilia A ; complications ; Humans ; Immune Tolerance ; drug effects ; Male ; Perioperative Care ; Postoperative Care

OBJECTIVETo compare the sensitivity and practicability of modified Bethesda assay and Nijmegen assay in detecting factor VIII (FVIII) inhibitor.

METHODSModified Bethesda assay and Nijmegen assay were used to screen FVIII inhibitors in 237 patients with hemophilia A. The buffer plus universal coagulation reference plasma (UCRP) was used to establish a standard curve for FVIII: C assay in modified Bethesda method, instead of Nijmegen plasma plus FVIII deficiency plasma in Nijmegen method. The cutoff value for positive FVIII inhibitors is > or = 0.6 BU/ml.

RESULTSThe positive rate of FVIII inhibitors was 5.5% (n = 13) when using modified Bethesda assay and was 8.4% (n = 20) when using Nijmegen assay (P > 0.05).

CONCLUSIONModified standard Bethesda assay is a convenient and feasible method for detecting FVIII inhibitors.

Adolescent ; Adult ; Autoantibodies ; blood ; Blood Coagulation Tests ; methods ; Child ; Child, Preschool ; Factor VIII ; immunology ; Female ; Hemophilia A ; blood ; immunology ; Humans ; Male ; Middle Aged ; Sensitivity and Specificity ; Young Adult

Blood Coagulation Factor Inhibitors ; antagonists & inhibitors ; blood ; Factor VIII ; administration & dosage ; antagonists & inhibitors ; immunology ; Hemophilia A ; drug therapy ; genetics ; immunology ; Humans ; Immune Tolerance ; Isoantibodies ; blood ; immunology ; Recombinant Proteins ; adverse effects ; immunology ; therapeutic use ; Risk Factors ; Time Factors