Autoantibodies to coagulation factors: From pathophysiology to diagnosis and therapy

Autoantibodies in Autoimmune Coagulation Factor Deficiencies: A Review of Inhibitory and Clearance-Accelerating Mechanisms from Japanese Practice

Autoimmune acquired coagulation factor deficiency (AiCFD) represents a rare coagulation disorder that primarily affects older people and sometimes causes fatal bleeding; therefore, clinicians need to consider this when encountering patients with unexplained bleeding. AiCFD is caused by the production of autoantibodies against one's own coagulation factor, which markedly inhibit its function, or accelerate its clearance from plasma, resulting in hemostatic failure. The plasma of affected patients shows various abnormal findings, because anti-coagulation factor autoantibodies are polyclonal, and each clone has different properties. First, inhibitor type autoantibodies target the functional sites of coagulation factors, thereby considerably reducing their activity. Second, clearance-accelerating autoantibodies bind to non-functional sites and cause rapid removal of coagulation factors from the blood, thereby reducing their levels (and their activity in parallel). Third, mixed type autoantibodies (inhibitory clearance-accelerating) substantially reduce coagulation factor activity and level to various degrees. Most anti-coagulation factor autoantibodies are inhibitory clearance-accelerating types, although pure inhibitor types remain clinically significant; however, the pure clearance-accelerating type appears to be rare, possibly because the autoantibody is not detected unless it exceeds the level of the target coagulation factor (pseudo-autoantibody negative). Moreover, anti-factor XIII autoantibodies are particularly complex, as they interfere with the A subunit (Aa type), its activated form (Ab type), and/or the B subunit (B type). Of the three types, Aa type anti-factor XIII autoantibodies contain a mixture of different inhibitor type autoantibodies in various ratios in plasma, resulting in an extremely diverse range of test findings. Therefore, care must be taken when diagnosing and assessing the efficacy of treatment.

Autoantibody development is associated with clinical severity of COVID-19: A cohort study

Viral infections, including respiratory diseases such as Coronavirus disease 2019 (COVID-19), are hypothesized to contribute to the onset of autoimmune disorders. Although elevated levels of autoantibodies have been observed following COVID-19, the role of specific autoantibodies linked to autoimmune diseases and their correlation with disease severity remains poorly defined. In this study, we used a comprehensive autoantibody panel to assess the autoantibody production across different cohorts of COVID-19 patients, categorized by disease severity. We also compared patients with severe COVID-19 to a control group with other severe, non-COVID-related diseases. Our findings indicate that the severity of COVID-19 corresponds to the overall production of specific autoantibodies, which are particularly associated with COVID-19. This association might predispose to an increased risk for the development of autoimmune conditions after a severe course of COVID-19.

Plasma proteomics in epilepsy: Network-based identification of proteins associated with seizures

PURPOSE

Identification of potential biomarkers of seizures.

METHODS

In this exploratory study, we quantified plasma protein intensities in 15 patients with recent seizures compared to 15 patients with long-standing seizure freedom. Using TMT-based proteomics we found fifty-one differentially expressed proteins.

RESULTS

Network analyses including co-expression networks and protein-protein interaction networks, using the STRING database, followed by network centrality and modularity analyses revealed 22 protein modules, with one module showing a significant association with seizures. The protein-protein interaction network centered around this module identified a subnetwork of 125 proteins, grouped into four clusters. Notably, one cluster (mainly enriching inflammatory pathways and Gene Ontology terms) demonstrated the highest enrichment of known epilepsy-related genes.

CONCLUSION

Overall, our network-based approach identified a protein module linked with seizures. The module contained known markers of epilepsy and inflammation. The results also demonstrate the potential of network analysis in discovering new biomarkers for improved epilepsy management.

Identification of fibrinogen as a plasma protein binding partner for lecanemab biosimilar IgG

OBJECTIVE

Recombinant monoclonal therapeutic antibodies like lecanemab, which target amyloid beta in Alzheimer's disease, offer a promising approach for modifying the disease progression. Due to its relatively short half-life, lecanemab administered as a bi-monthly infusion (typically 10 mg/kg) has a relatively brief half-life. Interaction with abundant plasma proteins binder in the bloodstream can affect pharmacokinetics of drugs, including their half-life. In this study, we investigated potential plasma protein binding (PPB) interaction to lecanemab using lecanemab biosimilar.

METHODS

Lecanemab biosimilar used in this study was based on publicly available sequences. ELISA and western blotting were used to assess lecanemab biosimilar immunoreactivity in the fractions of human plasma obtained through size exclusion chromatography. The binding of lecanemab biosimilar to candidate plasma binders was confirmed by western blotting, ELISA, and surface plasmon resonance analysis.

RESULTS

Using a combination of equilibrium dialysis, ELISA, and western blotting in human plasma, we first describe the presence of likely PPB partners to lecanemab biosimilar and then identify fibrinogen as one of them. Utilizing surface plasmon resonance, we confirmed that lecanemab biosimilar does bind to fibrinogen, although with lower affinity than to monomeric amyloid beta.

INTERPRETATION

In the context of lecanemab therapy, these results imply that fibrinogen levels could impact the levels of free antibodies in the bloodstream and that fibrinogen might serve as a reservoir for lecanemab. More broadly, these results indicate that PPB may be an important consideration when clinically utilizing therapeutic antibodies in neurodegenerative disease.

Diagnosis and Treatment of Autoimmune Acquired Coagulation Factor Deficiencies: An Evidence-Based Review of Japanese Practice

Among the acquired coagulation factor deficiencies, autoimmune coagulation factor deficiencies (AiCFD) are rare and result from autoantibody production against coagulation factors. In Japan, a nationwide survey on AiCFD has been conducted since 2009. Autoimmune factor XIII, factor VIII, von Willebrand factor, factor V, and factor X deficiencies (AiF13D, AiF8D, AiVWFD, AiF5D, and AiF10D, respectively) have been enacted as "designated intractable disease-282." The incidence of AiF8D, AiF13D, and AiF5D was 1.83, 0.044, and 0.038 per million people/year, respectively, whereas that of AiVWFD and AiF10D was not calculable owing to the small number of patients. AiF13D and AiF8D were often idiopathic, whereas AiVWFD was often associated with plasma cell neoplasms. Epistaxis was a characteristic symptom of AiVWFD, intramuscular bleeding was frequent in AiF13D and AiF8D, and subcutaneous bleeding (purpura) was frequent in AiF13D and AiF10D, although none were specific to any one disease. Differential diagnosis cannot be made based on bleeding symptoms alone; therefore, rapid and accurate testing is mandatory. Definitive diagnosis of AiCFD necessitates identifying the presence of coagulation factor "inhibitors" and/or "autoantibodies." Therefore, these tests should be performed upon unexplained severe acquired coagulation factor deficiencies. The mainstay of treatment for AiCFD was hemostatic therapy and autoantibody eradication therapy, which included the replacement of coagulation factors or "bypass" agents and administration of immunosuppressants. The rate of hemorrhagic death was high in AiF13D (13%), followed by AiF5D (7%) and Ai10D (5%); therefore, early diagnosis and optimal treatment are essential for AiCFDs. Given the unknown long-term prognosis, "intractable disease platform registries" have begun to accumulate in Japan.

Identification of Fibrinogen as a Plasma Protein Binding Partner for Lecanemab Biosimilar IgG: Implications for Alzheimer's Disease Therapy

OBJECTIVE

Recombinant monoclonal therapeutic antibodies like lecanemab, which target amyloid beta in Alzheimer's disease, offer a promising approach for modifying the disease progression. Due to its relatively short half-life, Lecanemab, administered as a bi-monthly infusion (typically 10mg/kg) has a relatively brief half-life. Interaction with abundant plasma proteins binder in the bloodstream can affect pharmacokinetics of drugs, including their half-life. In this study we investigated potential plasma protein binding interaction to lecanemab using lecanemab biosimilar.

METHODS

Lecanemab biosimilar used in this study was based on publicly available sequences. ELISA and Western blotting were used to assess lecanemab biosimilar immunoreactivity in the fractions human plasma sample obtained through size exclusion chromatography. The binding of lecanemab biosimilar to candidate binders was confirmed by Western blotting, ELISA, and surface plasmon resonance analysis.

RESULTS

Using a combination of equilibrium dialysis, ELISA, and Western blotting in human plasma, we first describe the presence of likely plasma protein binding partner to lecanemab biosimilar, and then identify fibrinogen as one of them. Utilizing surface plasmon resonance, we confirmed that lecanemab biosimilar does bind to fibrinogen, although with lower affinity than to monomeric amyloid beta.

CONCLUSION

In the context of lecanemab therapy, these results imply that fibrinogen levels could impact the levels of free antibodies in the bloodstream and that fibrinogen might serve as a reservoir for lecanemab. More broadly, these results indicate that plasma protein binding may be an important consideration when clinically utilizing therapeutic antibodies in neurodegenerative disease.

Successful Chemical Synovectomy in a Patient with Acquired von Willebrand Syndrome with Chronic Synovitis Due to Recurrent Knee Hemarthrosis: A Case Report

Acquired von Willebrand syndrome (AVWS) is a rare, non-hereditary bleeding disorder related to heterogeneous medical conditions such as hematological malignancies and cardiovascular and autoimmune diseases. We describe the clinical course of a 62-year-old man with polycythemia vera who experienced post-traumatic knee and leg swelling due to hemarthrosis. He was treated at another center with low molecular weight heparin due to misdiagnosed deep vein thrombosis further exacerbating the ongoing bleeding. At our center, he was diagnosed with AVWS with reduced von Willebrand factor (VWF):GPIbR plasma activity and loss of high molecular weight multimers (HMWM). He was treated with compressive bandages with resolution. Five months later, on clinical recurrence of knee and leg swelling, knee ultrasound scan showed the presence of chronic synovitis and a hemorrhagic Baker's cyst with signs of rupture. The treatment consisted of chemical synovectomy with rifampicin and steroids preceded by systemic replacement therapy using plasma-derived factor VIII-VWF concentrate. At the end of the treatment cycle, our patient reported complete resolution of knee pain and restoration of joint range of motion and function. Ultrasound evaluation confirmed complete resolution of knee capsule distension and Baker's cyst. Hemarthrosis is an anecdotal presentation of AVWS and chemical synovectomy was successful in treating this complication. A multidisciplinary approach allowed an effective management of this rare complication.

Clinical predictive model to estimate probability of remission in patients with lupus nephritis

BACKGROUND

Lupus nephritis (LN) is a major organ complication and cause of morbidity and mortality in patients with systemic lupus erythematosus. This study aims to provide the clinician with a quantitative tool for the prediction of the individual remission probability of LN and obtain new insights for improved clinical management in LN treatment.

METHODS

A total of 301 patients with renal biopsy-proven LN were recruited and randomly divided into model construction and validation group. The least absolute shrinkage and selection operator regression analysis was conducted to select significant variables, and a multivariate Cox regression predictive model was established. The performance of the model was verified and tested with 1000-bootstrap validation in the validation group. Finally, the nomogram was constructed, and the performance was evaluated. The predictive accuracy and efficiency were verified through receiver operation characteristic and calibration curves.

RESULTS

A total of 210 and 91 patients who all received renal biopsy were included in the training and validation group, respectively. A final prognostic model was established, which included the course of LN, gender, 24h-proteinuria, creatinine, triglycerides, FIB, Complement C3, anti-dsDNA antibody, tubular atrophy and classification of kidney biopsy. Moreover, an easy-to-use nomogram was built based on the predictive model. The areas under the curve (AUC) of the 1, 2, 5-year prediction were 77.12, 77.98 and 87.01 in the training group, respectively. In the validation group, the AUC of the 1, 2, 5-year prediction were 81.42, 87.20 and 92.81 respectively, which indicated good performance in predicting the remission probability of LN.

CONCLUSION

This novel model was constructed to predict the remission probability of patients with LN for the first time. This model displayed good predictive performance and was easy to use for clinical practice.

Massive haemorrhage: an unusual presentation of systemic lupus erythematosus

Systemic lupus erythematosus (SLE) usually affects young females and its presentation with haemorrhage is unusual. Intracerebral bleed (ICB) has been described in a few case reports, but massive haematuria has not been reported in the literature so far. Here, we present a case of a 56 year-old-lady who presented with expanding lobar bleed and massive haematuria as the first presentation of SLE secondary to vasculitis. Lupus vasculitis usually presents with thrombosis-related complications and although bleeding in this context is rare, it can lead to catastrophic consequences. Hence, vasculitis-related bleeding should be taken under consideration in a challenging situation like ours.

Plasma levels of D-dimer and fibrin degradation products correlate with bullous pemphigoid severity: a cross-sectional study

Bullous pemphigoid (BP), the most frequent blistering dermatosis in the elderly, is associated with increased mortality. The severity of BP can be assessed by detecting the anti-BP180 immunoglobulin G (IgG) concentration, but the lab test is not available in many community clinics. BP patients are usually in a hypercoagulable state with increased levels of D-dimer and fibrin degradation products (FDPs). We aimed to evaluate the use of D-dimer and FDPs in assessing BP severity. We compared the levels of plasma D-dimer, plasma FDPs, eosinophil counts, eosinophil cationic protein, and serum anti-BP180 IgG concentration between 48 typical BP patients and 33 Herpes zoster (HZ) patients (control group). Correlational analyses were conducted to determine the relationships between the lab values and common BP severity markers. The plasma D-dimer and FDP levels were higher in BP patients than in HZ controls (D-dimer: 3297 ± 2517 µg/L vs. 569.70 ± 412.40 µg/L; FDP: 9.74 ± 5.88 mg/L vs. 2.02 ± 1.69 mg/L, respectively, P < 0.0001). Significant positive correlations were found between D-dimer/FDP levels and BP severity markers (i.e. anti-BP180 IgG concentration [D-dimer: r = 0.3928, P = 0.0058; FDP: r = 0.4379, P = 0.0019] and eosinophil counts [D-dimer: r = 0.3625, P = 0.0013; FDP: r = 0.2880, P = 0.0472]) in BP patients. We also found an association between FDP and urticaria/erythema lesions (r = 0.3016, P = 0.0372), but no other BPDAI components. In 19 BP patients with complete remission after systemic glucocorticoid treatment, D-dimer and FDP levels decreased post-therapy (D-dimer: 5559 ± 7492 µg/L vs. 1738 ± 1478 µg/L; P < 0.0001; FDP: 11.20 ± 5.88 mg/L vs. 5.13 ± 3.44 mg/L; P = 0.0003), whereas they did not in BP patients with treatment resistant. Plasma D-dimer and FDP are convenient markers to evaluate BP severity assistant on BPDAI and eosinophil counts. FDP is also helpful for inflammatory lesions in BP patients.

Acquired hemophilia in a 7-year-old girl successfully treated with recombinant FVIIA and steroids: A case report

Acquired hemophilia should be evaluated in pediatric patients with bleeding and isolated prolonged aPTT. Immunosuppressive treatment should be initiated even in minor bleedings. Bypassing agents like rFVIIa can be used in children with success.

Treatment of acquired hemophilia A, a balancing act: results from a 27-year Dutch cohort study

Acquired hemophilia A (AHA) is a severe auto-immune bleeding disorder. Treatment of AHA is burdensome and optimal management is still unresolved. Therefore a retrospective nationwide multi-center cohort study (1992-2018) was performed to evaluate clinical presentation and treatment efficacy and safety of AHA in the Netherlands. Multivariate logistic and Cox regression analysis was used to study independent associations between patient characteristics and clinical outcomes. A total of 143 patients (median age 73 years; 52.4% male) were included with a median follow-up of 16.8 months (IQR 3.6-41.5 months). First-line immunosuppressive treatment was mostly steroid monotherapy (67.6%), steroids/cyclophosphamide (11.9%) and steroids/rituximab (11.9%), with success rates of 35.2%, 80.0% and 66.7% respectively, P < .05. Eventually 75% of patients achieved complete remission (CR). A high anti-FVIII antibody titer, severe bleeding and steroid monotherapy were associated with lower CR rates. Infections, the most important adverse event, occurred significantly more often with steroid combination therapy compared to steroids alone (38.7% vs 10.6%; P = .001). Overall mortality was 38.2%, mostly due to infections (19.2%) compared to 7.7% fatal bleeds. Advanced age, underlying malignancy and ICU admission were predictors for mortality. This study showed that AHA is characterized by significant disease-related and treatment-related morbidity and mortality. A high anti-FVIII titer, severe bleeding and steroid monotherapy were associated with a lower CR rate. The efficacy of steroid combination therapies however, was overshadowed by higher infection rates and infections represented the most important cause of death. The challenging and delicate balance between treatment effectivity and safety requires ongoing monitoring of AHA and further identification of prognostic markers.

Acquired Hemophilia A: A Potentially Fatal Bleeding Disorder

Acquired hemophilia A (AHA) is a rare autoimmune hematological disorder that has an incidence of about 1.5 cases per million people per year. It occurs in the elderly with the median age of 75 years, and most of the cases are idiopathic. It occurs due to the development of factor VIII inhibitor, which is an autoantibody against factor VIII leading to potentially life-threatening bleeding episodes. The diagnosis of AHA is often delayed and challenging. We report a case of an 86-year-old male who initially presented with signs and symptoms of a stroke. He was found to have oral mucosal bleeding and swelling of the floor of the mouth. He later developed epistaxis, hematuria, and melena. He had an isolated elevation of activated partial thromboplastin time (APTT) with very high levels of factor VIII inhibitor (1152 Bethesda units) and very low levels of Factor VIII (<1%). He was managed with supportive transfusion, bypass agents, and immunosuppressive therapy. AHA is a rare autoimmune bleeding disorder and is more commonly seen in the elderly population. Bleeding in AHA is usually sudden and sometimes life-threatening. Hence early hemostasis with bypassing agents and treatment with immunosuppressive agents should be initiated. Due to the rarity of the disorder, it is crucial to report AHA cases to create awareness and increase the index of suspicion of the clinicians for early diagnosis and treatment to prevent morbidity and mortality.

Management of rare acquired bleeding disorders

Autoantibodies toward clotting factors may develop in people suffering from autoimmune or neoplastic diseases, after drug intake or even in subjects without apparent conditions. They are more commonly directed against factor VIII (FVIII) or von Willebrand factor leading to acquired hemophilia A or acquired von Willebrand syndrome, respectively. Rarely, autoantibodies develop against other clotting factors, such as fibrinogen, FII, FV, FVII, FX, FXI, and FXIII. The clinical picture of an acquired bleeding disorder includes a wide spectrum of clinical manifestations ranging from minimal or no bleeding to life-threatening events. Patients with no previous personal or family history of bleeding may have sudden-onset hemorrhagic manifestations, sometimes fatal, especially if an early diagnosis is not made. On the other hand, some patients may not have hemorrhagic symptoms at onset, and their diagnosis can therefore be delayed. The laboratory diagnostic assessment is performed by screening coagulation tests followed by specific factor-level measurement and inhibitor-titrating assays. An early diagnosis of acquired coagulopathies is mandatory for starting the appropriate treatment aimed at both controlling the acute bleeding episode mainly using the bypassing agents, and eradicating the anticlotting factor autoantibody, using immunosuppressive treatment. Therefore, prompt intervention by an expert and a specialized center is needed for immediate recognition and treatment of the disease.

Tocilizumab Effects on Coagulation Factor XIII in Patients with Rheumatoid Arthritis

Introduction

Rheumatoid arthritis (RA) is a chronic systemic auto-immune disease associated with a prothrombotic state. Tocilizumab, an interleukin-6 receptor inhibitor, is highly effective in controlling disease activity and thrombotic risk. Factor XIII (FXIII), involved in thrombotic complications, has been reported to be reduced in RA patients during maintenance treatment with tocilizumab, but no data are available before and after the drug administration. Thus, we investigated the effects of tocilizumab on FXIII, thrombin generation and inflammation in patients with RA naïve for the drug.

Methods

We studied 15 consecutive adult patients with RA at baseline and 4 weeks after the onset of parenteral administration of tocilizumab, measuring disease activity and plasma levels of C-reactive protein (CRP), FXIII, and prothrombin fragments F1+2 by immunoenzymatic methods. Fifteen healthy subjects, sex-and age-matched with patients, served as normal controls for laboratory measurements.

Results

At baseline, patients with established RA had a median DAS28 of 4.8 (3.2–8.3) and, compared to healthy controls, had higher plasma levels of CRP (p < 0.0001), FXIII (p = 0.017) and F1+2 (p < 0.0001). Four weeks after starting treatment with tocilizumab, based on the EULAR response criteria, eight patients were classifiable as responders and seven as non-responders. In responders, we observed a statistically significant reduction not only of the values of DAS28 and CRP (p = 0.012 for both), ut also of plasma levels of FXIII (p = 0.05) and F1+2 (p = 0.025). In non-responders, all the studied parameters were unchanged.

Conclusion

The decrease of FXIII and F1+2 levels after tocilizumab treatment observed only in those patients who responded to the drug indicates that the effect of tocilizumab on the prothrombotic state is linked to the control of inflammation and disease activity and not to a direct effect of the drug, thus contributing to the reduction of the cardiovascular risk.

Acquired Hemophilia A (FVIII Deficiency) Associated with Papillary Thyroid Cancer: Treatment with Recombinant Porcine FVIII

Acquired hemophilia A (AHA) is a rare autoimmune disorder caused by autoantibodies against Factor VIII (FVIII). It has a high mortality due to bleeding complications. FVIIa-based bypassing agents are the first line of treatment but not always effective. Recombinant porcine (rp) FVIII (Obizur®) was recently approved for rescue treatment but with little evidence-based information regarding efficacy. We report a case of papillary thyroid cancer associated with AHA malignancy that responded to a single dose of rpFVIII after failure to achieve hemostasis with FVIIa-based bypassing products.

Dramatic decreases of all haemorrhagic coagulation factors by acquired inhibitors after extended left lobectomy

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Required inhibitors of all coagulation factors.

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After liver resection.

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Severe bleeding.

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Benefits of using steroid.

Introduction

Acquired inhibition of coagulation factors is a rare disease, and the diagnosis is often difficult and delayed. We experienced a deficiency in all coagulation factors after hepatobiliary surgery.

Case Presentation

Extended left liver resection was undertaken and hepaticojejunostomy was performed in a 70-year-old man. He had suffered from a high fever caused by cholangitis for 35 days. The major cause was a narrowing of the hepaticojejunostomy, and reconstruction was carried out. Twenty-four days later, there was a sudden massive bleed from his nose and the surgical site. Steroid pulse therapy was used as a treatment because cross mixing and some blood tests revealed the patient was experiencing an inhibition of all coagulation factors, and consequently the levels of coagulation factors dramatically recovered.

Discussion

We considered malignancy and surgical damages to be the underlying cause. The reported treatment and examination will help clinicians explore additional reasons for massive bleeding after a severe physical injury.

Conclusion

We have described the first case of acquired inhibition of all coagulation factors associated with extended left lobectomy.

Pregnancy-related acquired hemophilia A initially manifesting as pleural hemorrhage: A case report

RATIONALE

Acquired hemophilia A is a rare hemorrhagic disease in which the body produces specific antibodies that attack factor VIII, resulting in bleeding that is mainly mucocutaneous and associated with soft tissue and the gastrointestinal system. Approximately 50% of this disease derives from basic diseases, such as autoimmune diseases, cancer, and pregnancy.

PATIENT CONCERNS

We report a 35-year-old postpartum female with acquired hemophilia A who initially presented with pleural hemorrhage.

DIAGNOSES

In this patient activated prothrombin time (PT) and activated partial thromboplastin time (APTT) were found, and the factor VIII activity was 12.6%, furthermore Bethesda assay showed a FVIII antibody titer of 7.4 Bethesda units (BUs).

INTERVENTIONS

The treatment requires a 2-pronged approach: treatment of the bleeding and elimination of the inhibitor.

OUTCOMES

After hemostatic agents were used and inhibitors were eradicated, the patient achieved complete remission without relapse.

LESSONS

It is essential to recognize the development of disease earlier in pregnant woman.

Acquired Hemophilia A Presenting as Intramuscular Hematoma

Acquired hemophilia A poses a clinical and diagnostic challenge. Although rare, it is still the most common acquired factor deficiency. We present a case of acquired hemophilia A diagnosed in a 71-year-old female who presented with a right thigh hematoma of acute onset. The diagnosis was established based on the coagulation profile along with factor VIII levels, mixing studies, and inhibitor levels. The patient received multiple lines of therapy including steroids, factor VIIa, Obizur (porcine-derived recombinant factor VIII), followed by multiple cycles of chemotherapy including cyclophosphamide and rituximab.

Successful treatment of acquired hemophilia A associated with immune thrombocytopenia and joint hemarthrosis: A case report and literature review

INTRODUCTION

Acquired hemophilia A (AHA) is a rare bleeding disease caused by autoantibodies against factor VIII (FVIII). Spontaneous bleeding symptoms usually affect the skin, musco, muscle, and internal organs, while joint hemarthrosis in AHA is an extremely rare manifestation. AHA may have an autoimmune cause and is often associated with autoimmune disease, but no demonstrable platelet impairment was found in AHA patients. We report a patient with AHA complicated with a right shoulder joint hemarthrosis and immune thrombocytopenia. The patient was treated with fresh frozen plasma (FFP) and human prothrombin complex concentrate (hPCC) to control the active bleeding. Simultaneously this patient firstly accepted cyclophosphamide combined with prednisone to eradicate the inhibitor, while the treatment effect of cyclophosphamide combined with prednisone was not satisfactory. At last, she was successfully treated through the use of an anti-CD20 monoclonal antibody.

CONCLUSION

AHA is an autoimmune disease and can co-exist with immune cytopenia besides connective tissue disease (CTD). Joint hemarthrosis is not specific to congenital hemophilia and mainly related to the extent of prolonged aPTT and weight loading of joint in AHA. When the first-line therapy of cyclophosphamide combined with prednisone is not enough to eradicate the inhibitor, especially for a higher inhibitor titer, anti-CD20 monoclonal antibody could play an important role.

Perioperative Management of Patients with Inflammatory Rheumatic Diseases Undergoing Major Orthopaedic Surgery: A Practical Overview

Patients with inflammatory rheumatic diseases often need orthopaedic surgery due to joint involvement. Total hip replacement and total knee replacement are frequent surgical procedures in these patients. Due to the complexity of the inflammatory rheumatic diseases, the perioperative management of these patients must envisage a multidisciplinary approach. The frequent association with extraarticular comorbidities must be considered when evaluating perioperative risk of the patient and should guide the clinician in the decision-making process. However, guidelines of different medical societies may vary and are sometimes contradictory. Orthopaedics should collaborate with rheumatologists, anaesthesiologists and, when needed, cardiologists and haematologists with the common aim of minimising perioperative risk in patients with inflammatory rheumatic diseases. The aim of this review is to provide the reader with simple practical recommendations regarding perioperative management of drugs such as disease-modifying anti-rheumatic drugs, corticosteroids, non-steroidal anti-inflammatory drugs and tools for a risk stratification for cardiovascular and thromboembolic risk based on current evidence for patients with inflammatory rheumatic diseases.

What should be the laboratory approach against isolated prolongation of a activated partial thromboplastin time?

BACKGROUND

This study is a retrospective evaluation of patients who were subject to mixing study in our laboratory due to prolonged APTT. The preliminary diagnoses, clinical manifestations, and results of additional ordered tests were reviewed. The study aims to investigate whether repeating APTT test with a different assay prior to performing mixed study in patients with prolonged APTT would be a better alternative algorithmic approach in order to save both time and costs.

METHODS

We retrospectively evaluated 166 patients (65 females and 101 males) who were subject to mixing study due to isolated prolonged APTT. Additional ordered tests to identify the etiology and clinical findings were reviewed. All patients who had prolonged APTT as a result of testing with Hemosil Synthasil APTT reagent in ACL TOP analyzer were repeated with Stago Cephascreen APTT reagent in STA-R coagulation analyzer.

RESULTS

APTT test was requested preoperatively in 72.2% of cases. Only 6.6% of the cases had history of bleeding. Correction with mixing study was achieved in 122 (73.5%) cases, among which 75 (45%) cases were found to have APTT test results within reference range when tested with Cephascreen reagent. In 44 (26.5%) cases, mixing study did not result in correction. Only 4 cases were confirmed to have lupus anticoagulants (LA), while 4 cases were diagnosed with hemophilia with inhibitors.

CONCLUSION

Prolonged APTT results should always be retested using a different assay prior to mixing study. The clinician and the laboratory specialist should collaborate at the postanalytical phase.

Long-Term Safety of PEGylated Coagulation Factor VIII in the Immune-Deficient Rowett Nude Rat

Turoctocog alfa pegol (N8-GP) is a glycoPEGylated human recombinant factor VIII for the treatment of hemophilia A. The safety profile of rFVIII, and polyethylene glycols (PEG) technology, is well-established. Conducting long-term toxicity studies in animals using human proteins can be complicated by anti-drug antibody (ADA) development. To evaluate long-term safety of N8-GP, 26- and 52-week toxicity studies were conducted in immune-deficient rats dosed intravenously every fourth day with 0, 50, 150, 500, or 1200 IU/kg N8-GP. Observations included clinical observations, body weight, ophthalmoscopy, hematology, chemistry, coagulation, urinalysis, toxicokinetics, antibody analysis, and macroscopic/microscopic organ examination. Immunohistochemical staining examined the distribution of PEG in the brain. No adverse test item-related findings were seen and PEG was not detected in the brain. Exposure was confirmed for ~75% of the animals dosed with 500 and 1200 IU/kg N8-GP; the high lower limit of quantification of the bioanalysis assay prevented confirmation of exposure in the lower doses. A small number of animals developed ADAs, and the proportion of animals surviving until scheduled termination was >80%. N8-GP was well tolerated, and the immune-deficient rat proved suitable for testing long-term toxicity of human proteins that are immunogenic in animals.

Congenital and acquired bleeding disorders in pregnancy

Obstetrical hematology represents challenges not only for the patient, but also for her progeny. In particular, bleeding disorders, both congenital and acquired, not only present problems both for delivery and in the immediate postpartum period, but also may have significant implications for the fetus and neonate. Women with congenital bleeding disorders or who are carriers of X-linked or autosomal disorders should be counseled prior to conception so that pregnancy can be safely undertaken with careful preparation. A treatment plan should be set up by a specialized care team that includes the hematologist, obstetrician, and anesthesiologist; the patient should be followed closely during pregnancy, through delivery, and in the immediate postpartum period. Acquired disorders of hemostasis that occur with pregnancy may present particular diagnostic difficulties and require rapid diagnosis and management.

Acquired haemophilia: an overview for clinical practice

Acquired haemophilia is a potentially life-threatening bleeding disorder caused by the development of autoantibodies against coagulation factors, most commonly against factor (F) VIII (acquired haemophilia A; AHA). In around half of patients, an underlying disorder is associated with AHA; the remaining cases are idiopathic. Typically, the disorder presents with bleeding, ranging from mild to life- and limb-threatening, in patients with no personal or family bleeding history. Diagnosis involves an isolated prolongation of the activated partial thromboplastin time, without correction in mixing studies, low FVIII activity levels and evidence of a FVIII inhibitor. As AHA is rare, a lack of familiarity of the condition may result in delayed diagnosis, and prompt haemostatic control is required to reduce morbidity and mortality. Bypassing agents (recombinant activated factor VII or activated prothrombin complex concentrates) can be used to control acute bleeding, and immunosuppression is necessary to eradicate the inhibitor. As clinical trials in this rare and heterogeneous disease are difficult, current evidence comes from observational studies, including registries. This review will focus on the diagnostic and therapeutic challenges of AHA and summarise how understanding of this complex condition has increased based on recent registry data.

Pre-existing Antibody: Biotherapeutic Modality-Based Review

Pre-existing antibodies to biotherapeutic drugs have been detected in drug-naïve subjects for a variety of biotherapeutic modalities. Pre-existing antibodies are immunoglobulins that are either specific or cross-reacting with a protein or glycan epitopes on a biotherapeutic compound. Although the exact cause for pre-existing antibodies is often unknown, environmental exposures to non-human proteins, glycans, and structurally similar products are frequently proposed as factors. Clinical consequences of the pre-existing antibodies vary from an adverse effect on patient safety to no impact at all and remain highly dependent on the biotherapeutic drug modality and therapeutic indication. As such, pre-existing antibodies are viewed as an immunogenicity risk factor requiring a careful evaluation. Herein, the relationships between biotherapeutic modalities to the nature, prevalence, and clinical consequences of pre-existing antibodies are reviewed. Initial evidence for pre-existing antibody is often identified during anti-drug antibody (ADA) assay development. Other interfering factors known to cause false ADA positive signal, including circulating multimeric drug target, rheumatoid factors, and heterophilic antibodies, are discussed.

Challenges and open issues in the management of acquired hemophilia A (AHA)

Acquired hemophilia A (AHA) is a rare autoimmune bleeding disorder caused by antibodies which neutralize the function of factor VIII (FVIII). The disease presents a complex clinical challenge to the treating Physicians and Hematologists. As the disease is associated with high mortality, prompt management is necessary. Early recognition, quick diagnosis and timely referral to a specialized center are important for better management of these patients. The different clinical manifestations, underlying pathology, inhibitor kinetics and the associated age related comorbidities do not allow extrapolation of the treatment protocols of congenital hemophilia to AHA. The basic strategies of the management of AHA patients involve maintaining hemostasis, suppression or eradication of antibodies, diagnosis and treatment of underlying pathology and avoid treatment related complications like thrombosis. The efficiency of hemostatic agents which are generally used to treat AHA is unpredictable. Due to the rarity of the disease, there are no randomized clinical trials on the management of this disorder and thus the expertise and experience of the treating Physicians' guide treatment strategies.

A Comparison of Efficacy Between Recombinant Activated Factor VII (Aryoseven) and Novoseven in Patients With Hereditary FVIII Deficiency With Inhibitor

Introduction:

This study compared the efficacy of Aryoseven with Novoseven to control bleeding episodes in patients with hemophilia A with inhibitors.

Methods:

Sixty-six patients were randomized into 2 groups, with 4 consecutive block randomization. These groups received Aryoseven and Novoseven dosages of 90 to 120 μg/kg intravenously every 2 hours.

Results:

Median (interquartile range) level of factor VIII (FVIII) inhibitor in groups A and B was 15.0 and 19.0 Bethesda Unit (BU) preadministration. Bleeding onset in group A was 1246 ± 1104 minutes and in group B was 2301 ± 1693 minutes ( P = .311). The Kavakli global response scores and treatment success rate was comparable in both the groups. The side effects in groups A (9.7%) and B (2.9%) were comparable.

Conclusion:

Biosimilar recombinant activated FVII is found to be as effective as Novoseven in the treatment of acute joint bleeding in patients with hemophilia with inhibitors. Its usage will decrease the gaps in hemophilia.

Hypercoagulability in celiac disease--an update

Celiac disease is a life-long autoimmune disease affecting multiple organs of genetically susceptible individuals. One of the extra intestinal manifestations of the disease is thromboembolic events like strokes, veins' thrombosis, and pregnancy losses. Hypercoagulable autoimmune diseases like lupus erythematosus and antiphospholipid syndrome, associated with celiac disease just add risk to the patients. Pathogenic predisposing avenues increasing the hypercoagulability in celiac disease are multiple: nutritional deficiencies (B12, folate, and vitamin K), genetic predisposition (MTHFR mutations), thrombophilic autoantibodies, hyperhomocysinemia, endothelial dysfunction and platelet abnormalities. Primary pharmacologic thromboprophylaxis or treating the predisposing factors should be considered on a personal basis.

[Acquired haemophilia A: two cases]

BACKGROUND

Acquired haemophilia A (AH) is an uncommon bleeding disorder that presents as multiple, disseminated spontaneous subcutaneous bleeds. Diagnosis may be made on the basis of prolonged activated partial thromboplastin time (aPTT). The severity of the disease is associated with the low risk of haemoglobin levels and with potential links with other diseases.

OBSERVATIONS

Two men were hospitalized for extensive and spontaneous subcutaneous hematoma. In both cases, the International Normalized Ratio (INR) was normal, but aPTT was 3 times higher than normal. Autoantibodies against coagulation factor VIII confirmed the diagnosis of AH. The patients received immunomodulatory treatment. In one patient, diffuse large B-cell lymphoma was discovered one year after successful treatment of AH.

DISCUSSION

AH may be revealed by areas of bruising, subutaneous haematomas mimicking erythema nodosum, and muscle pain. APTT results alone can prompt the biologist to screen for factor VIII inhibitors. Aside from the risk of fatal bleeding, in half of all cases, the prognosis is determined by associated disorders such as blood dyscrasias, solid tumours, autoimmune diseases, use of certain medicines and pregnancy. After treatment for bleeding complications, therapy focuses on restoring the coagulation time. The aim of immunomodulatory therapy is to stem production of autoantibodies against coagulation factor VIII.

CONCLUSION

AH must be considered rapidly in order to reduce the risk of bleeding emergencies and to screen for potential related diseases.

Salvage therapy with high dose Intravenous Immunoglobulins in acquired Von Willebrand Syndrome and unresponsive severe intestinal bleeding

A 91-year-old woman affected with acquired Von Willebrand (VW) syndrome and intestinal angiodysplasias presented with severe gastrointestinal bleeding (hemoglobin 5 g/dl). Despite replacement therapy with VW factor/factor VIII concentrate qid, bleeding did not stop (eleven packed red blood cell units were transfused over three days). High circulating levels of anti-VW factor immunoglobulin M were documented immunoenzimatically. Heart ultrasound showed abnormalities of the mitral and aortic valves with severe flow alterations. When intravenous immunoglobulins were added to therapy, prompt clinical and laboratory responses occurred: complete cessation of bleeding, raise in hemoglobin, VW factor antigen, VW ristocetin cofactor and factor VIII levels as well as progressive reduction of the anti-VWF autoantibody levels.

High-resolution mapping of epitopes on the C2 domain of factor VIII by analysis of point mutants using surface plasmon resonance

Neutralizing anti-factor VIII (FVIII) antibodies that develop in patients with hemophilia A and in murine hemophilia A models, clinically termed "inhibitors," bind to several distinct surfaces on the FVIII-C2 domain. To map these epitopes at high resolution, 60 recombinant FVIII-C2 proteins were generated, each having a single surface-exposed residue mutated to alanine or a conservative substitution. The binding kinetics of these muteins to 11 monoclonal, inhibitory anti-FVIII-C2 antibodies were evaluated by surface plasmon resonance and the results compared with those obtained for wild-type FVIII-C2. Clusters of residues with significantly altered binding kinetics identified "functional" B-cell epitopes, defined as those residues contributing appreciable antigen-antibody avidity. These antibodies were previously shown to neutralize FVIII activity by interfering with proteolytic activation of FVIII by thrombin or factor Xa, or with its binding to phospholipid surfaces, von Willebrand factor, or other components of the intrinsic tenase complex. Fine mapping of epitopes by surface plasmon resonance also indicated surfaces through which FVIII interacts with proteins and phospholipids as it participates in coagulation. Mutations that significantly altered the dissociation times/half-lives identified functionally important interactions within antigen-antibody interfaces and suggested specific sequence modifications to generate novel, less antigenic FVIII proteins with possible therapeutic potential for treatment of inhibitor patients.

Acquired hemophilia A: a frequently overlooked autoimmune hemorrhagic disorder

Acquired hemophilia A (AHA) is a rare hemorrhagic disease in which autoantibodies against coagulation factor VIII- (FVIII-) neutralizing antibodies (inhibitors) impair the intrinsic coagulation system. As the inhibitors developed in AHA are autoantibodies, the disease may have an autoimmune cause and is often associated with autoimmune disease. Although acute hemorrhage associated with AHA may be fatal and is costly to treat, AHA is often unrecognized or misdiagnosed. AHA should thus be considered in the differential diagnosis particularly in postpartum women and the elderly with bleeding tendency or prolonged activated partial thromboplastin time. Cross-mixing tests and measurement of FVIII-binding antibodies are useful to confirm AHA diagnosis. For treatment of acute hemorrhage, hemostatic therapy with bypassing agents should be provided. Unlike in congenital hemophilia A with inhibitors, in which immune tolerance induction therapy using repetitive infusions of high-dose FVIII concentrates is effective for inhibitor eradication, immune tolerance induction therapy has shown poor efficacy in treating AHA. Immunosuppressive treatment should thus be initiated to eradicate inhibitors as soon as the diagnosis of AHA is confirmed.