Acquired hemophilia A associated with Epstein–Barr-virus-associated T/natural killer-cell lymphoproliferative disease: A case report

Introduction:Acquired hemophilia A (AHA) is a rare bleeding disorder caused by autoantibodies against factor VIII (FVIII). Hematological malignancies, especially lymphoid malignancies, are known to be underlying causes of AHA; however, thus far, there is no report of AHA associated with Epstein–Barr-virus-associated T/natural killer-cell lymphoproliferative disease (EBV-T/NK-LPD). Here, we present a case of AHA that developed during treatment for EBV-T/NK-LPD.History:A 69-year-old man visited our hospital because of general fatigue. Blood examination showed pancytopenia, and computed tomography revealed whole-body lymphadenopathy, but there were no findings indicating hematological malignancy from bone marrow aspiration and cervical lymph node biopsy. The level of EBV DNA in peripheral blood was extremely high, and he was diagnosed with EBV-T/NK-LPD. EBV-T/NK-LPD improved with prednisolone (PSL) administration. Seventeen months after starting treatment, the patient complained of back and right leg pain. At that time, he had been treated with low-dose PSL, and EBV-T/NK-LPD was well controlled. Imaging revealed hematoma of the right iliopsoas muscle. Prolonged activated partial thromboplastin time (APTT) was the only abnormal finding in a screening coagulation test. FVIII coagulant activity was below detection limit, and FVIII inhibitor level was increased. From these results, he was diagnosed with AHA.A higher dose of PSL was administered, and, after 1 month of treatment, FVIII activity gradually increased, and FVIII inhibitor level became undetectable. APTT also normalized, and complete remission was achieved and maintained for 13 months with low-dose PSL. During treatment, EBV-T/NK-LPD was well controlled.Conclusion:It is speculated that proliferating lymphocytes interfere with normal immune functions and that abnormal autoantibodies are produced from those lymphocytes in patients with LPD. Therefore, we speculate that EBV-infected and proliferating monoclonal NK cells might have modulated the immune system and produced autoantibodies against FVIII, thus causing AHA in this patient with EBV-T/NK-LPD.     

Acquired hemophilia in a patient with systemic lupus erythematosus: a case report and literature review

Abstract

We report the case of a 38-year-old female patient with systemic lupus erythematosus (SLE) who developed acquired hemophilia caused by factor VIII (FVIII) inhibitors. She manifested spontaneous bleeding symptoms such as ecchymoses and hematuria. Laboratory findings showed an isolated prolongation of the activated partial thromboplastin time, reduced FVIII activity, and a high titer of FVIII inhibitors. She was successfully treated with oral predonisolone and cyclosporine in combination with steroid and cyclophosphamide pulse therapy.     

The tipping point: The critical role of therapeutic apheresis in a case of refractory acquired hemophilia

Acquired hemophilia A (AHA) is a rare autoimmune disorder that leads to factor VIII (FVIII) deficiency via autoantibody formation. Standard treatment options include FVIII bypassing factors and immunosuppression. However, the role of therapeutic plasma exchange (TPE) is not clear in the treatment of AHA. We present a case of idiopathic AHA in a 66 year old female with severe bleeding and a FVIII inhibitor of 17.6 Bethesda units (BU). She failed to respond to standard treatment including maximum dose of recombinant FVIIa (rFVIIa), rituximab, and other immunosuppressive agents. Her FVIII inhibitor rapidly increased to 140 BU and FVIII was below 5%. TPE was initiated 3 weeks after admission and her bleeding stabilized after the first treatment and completely stopped after three treatments. Repeat testing revealed increased FVIII to 15% and FVIII inhibitor decreased to 2.0 BU. After an additional TPE treatment, her FVIII increased to 27% and FVIII inhibitor decreased to 0.6 BU and she was discharged without bleeding 40 days after admission. In this case, TPE played a critical role in reducing FVIII inhibitor, which resulted in a recovery of FVIII activity and hemostasis. Therefore, TPE should be initiated early in AHA patients with bleeding and high titer of FVIII inhibitor.     

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.     

Management of acquired hemophilia A: Review of current evidence

Acquired hemophilia A (AHA) is a rare acquired bleeding disorder caused by autoantibodies against autologous factor VIII (FVIII). It is a disease that most commonly affects the elderly, but it has been described in children and during the post-partum period. It is idiopathic in 50% of cases and is associated with autoimmune disease, malignancy, pregnancy, infection or certain medications in the other 50%. The diagnosis should be suspected in patients with an isolated prolonged aPPT without previous personal or familial bleeding history. Treating the bleeding and eradication of the inhibitor is the mainstay of treatment. The first line of treatment for acute bleeding is the use of bypassing agents. The most commonly used method for eradicating the inhibitor is immunosuppression, namely corticosteroids alone or in combination with cyclophosphamide. This review summarises current knowledge and reviews management options and guidelines.     

The chaperone‐like sodium phenylbutyrate improves factor IX intracellular trafficking and activity impaired by the frequent p.R294Q mutation

Essentials

• Missense mutations often impair protein folding, and thus intracellular trafficking and secretion.
• Cellular models of severe type I hemophilia B were challenged with chaperone‐like compounds.
• Sodium phenylbutyrate improved intracellular trafficking and secretion of the frequent p.R294Q.
• The increased coagulant activity levels (～3%) of p.R294Q would ameliorate the bleeding phenotype.

Summary

Background

Missense mutations often impair protein folding and intracellular processing, which can be improved by small compounds with chaperone‐like activity. However, little has been done in coagulopathies, where even modest increases of functional levels could have therapeutic implications.

Objectives

To rescue the expression of factor IX (FIX) variants affected by missense mutations associated with type I hemophilia B (HB) through chaperone‐like compounds.

Methods

Expression studies of recombinant (r)FIX variants and evaluation of secreted levels (ELISA), intracellular trafficking (immunofluorescence) and activity (coagulant assays) before and after treatment of cells with chaperone‐like compounds.

Results

As a model we chose the most frequent HB mutation (p.R294Q, ~100 patients), compared with other recurrent mutations associated with severe/moderate type I HB. Immunofluorescence studies revealed retention of rFIX variants in the endoplasmic reticulum and negligible localization in the Golgi, thus indicating impaired intracellular trafficking. Consistently, and in agreement with coagulation phenotypes in patients, all missense mutations resulted in impaired secretion (< 1% wild‐type rFIX). Sodium phenylbutyrate (NaPBA) quantitatively improved trafficking to the Golgi and dose dependently promoted secretion (from 0.3 ± 0.1% to 1.5 ± 0.3%) only of the rFIX‐294Q variant. Noticeably, this variant displayed a specific coagulant activity that was higher (~2.0 fold) than that of wild‐type rFIX in all treatment conditions. Importantly, coagulant activity was concurrently increased to levels (3.0 ± 0.9%) that, if achieved in patients, would ameliorate the bleeding phenotype.

Conclusions

Altogether, our data detail molecular mechanisms underlying type I HB and candidate NaPBA as affordable ‘personalized’ therapeutics for patients affected by the highly frequent p.R294Q mutation, and with reduced access to substitutive therapy.

     

In‐depth comparison of N‐glycosylation of human plasma‐derived factor VIII and different recombinant products: from structure to clinical implications

Essentials

• Glycosylation heterogeneity of recombinant proteins affects pharmacokinetics and immunogenicity.
• N‐glycomics/glycoproteomics of plasma‐derived Factor VIII and 6 recombinant FVIIIs were compared.
• Depending on cell line, significant differences to plasma‐derived FVIII were observed.
• Recombinant FVIIIs expressed distinct and immunologically relevant epitopes.

Summary

Background/Objective

Human factor VIII (FVIII) is a plasma glycoprotein, defects of which result in hemophilia A. Current substitution therapy uses FVIII products purified from human plasma or from various cell lines (recombinant FVIII) with different levels of B‐domain deletion. Glycosylation is a post‐translational protein modification in FVIII that has a substantial influence on its physical, functional and antigenic properties. Variation in glycosylation is likely to be the reason that FVIII products differ in their pharmacokinetics, pharmacodynamics and immunogenicity. However, the literature on FVIII glycosylation is inconsistent, preventing assembly into a coherent model. Seeking to better understand the glycosylation mechanisms underlying FVIII biology, we studied the N‐glycosylation of human plasma‐derived (pd)FVIII and six rFVIII products expressed in CHO, BHK or HEK cell lines.

Methods

FVIII samples were subjected to head‐to‐head detailed glycomic and glycoproteomic characterization using a combination of MALDI‐MS and MS/MS, GC‐MS and UPLC‐UV‐MS^E technologies.

Results/Conclusion

The results of our study detail the N‐glycan repertoire of pdFVIII to an unprecedented level, and for the first time, provide evidence of N‐glycolylneuraminic acid (NeuGc) found on pdFVIII. Although site‐specific glycosylation of rFVIII proved consistent with pdFVIII regardless of the expression system, the entire N‐glycan content of each sample appeared significantly different. Although the proportion of biologically important epitopes common to all samples (i.e. sialylation and high‐mannose) varied between samples, some recombinant products expressed distinct and immunologically relevant epitopes, such as LacdiNAc (LDN), fucosylated LacdiNAc (FucLDN), NeuGc, Lewis^X/Y and Gal_α1,3Gal epitopes. rFVIII expressed in HEK cells showed the greatest glycomic differences to human pdFVIII.     

Nano‐evidence for joint microbleeds in hemophilia patients

The concept of joint microbleeding in hemophilia patients was first proposed over 10 years ago. This was based on unexpected abnormalities found in medical imaging studies of asymptomatic joints. Since then, there have been no published studies confirming the presence of joint microbleeds. This critique will review the evidence for and against joint microbleeding in hemophilia patients and the potential implications.