•Seventy-eight percent of patients with AHA were found to have autoantibodies against targets other than factor VIII.•The data suggest that a generalized breakdown of self-tolerance mechanisms is ...involved in the pathology of AHA.
Display omitted
The root cause of autoantibody formation against factor VIII (FVIII) in acquired hemophilia A (AHA) remains unclear. We aimed to assess whether AHA is exclusively associated with autoantibodies toward FVIII or whether patients also produce increased levels of autoantibodies against other targets. A case-control study was performed enrolling patients with AHA and age-matched controls. Human epithelial cell (HEp-2) immunofluorescence was applied to screen for antinuclear (ANA) and anticytoplasmic autoantibodies. Screening for autoantibodies against extractable nuclear antigens was performed by enzyme immunoassay detecting SS-A/Ro, SS-B/La, U1RNP, Scl-70, Jo-1, centromere B, Sm, double-stranded DNA, and α-fodrin (AF). Patients with AHA were more often positive for ANA than control patients (64% vs 30%; odds ratio OR 4.02, 1.98-8.18) and had higher ANA titers detected than controls. Cytoplasmic autoantibodies and anti-AF immunoglobulin A autoantibodies were also more frequent in patients with AHA compared with controls. Autoantibodies against any target other than FVIII were found in 78% of patients with AHA compared with 46% of controls (OR 4.16, 1.98-8.39). Results were similar preforming sensitivity analyses (excluding either subjects with autoimmune disorders, cancer, pregnancy, or immunosuppressive medication at baseline) and in multivariable binary logistic regression. To exclude that autoantibody staining was merely a result of cross-reactivity of anti-FVIII autoantibodies, we tested a mix of 7 well-characterized monoclonal anti-FVIII antibodies. These antibodies did not stain HEp-2 cells used for ANA detection. In conclusion, a diverse pattern of autoantibodies is associated with AHA, suggesting that a more general breakdown of immune tolerance might be involved in its pathology.
Patients with Philadelphia-negative myeloproliferative neoplasms (MPNs), particularly those carrying the JAK2
mutation, are at increased risk of thrombosis. While an association of MPNs with ...autoimmune disorders has been established, the prevalence of inherited or acquired thrombophilias in JAK2
-positive patients remains obscure. We therefore investigated the coincidence of the JAK2
mutation with additional thrombogenic risk factors.
In a retrospective study, we analyzed all patients referred for thrombophilia work-up between 01/2011 and 08/2019, in whom additional JAK2
mutation analysis was performed because of thromboembolic events that were recurrent, atypically located and/or associated with abnormal blood counts.
Of 472 tested patients, 49 (10.4%) were JAK2
-positive. While the frequency of inherited thrombophilias (factor V Leiden and prothrombin G20210A mutation, deficiency of antithrombin, protein C, protein S) was not different between the two groups, the prevalence of definite antiphospholipid syndrome (APS), mostly associated with a moderate- or high-risk antibody profile, was significantly higher in patients with (22.4%) than in those without (8.4%) JAK2
mutation (p < 0.01). All evaluable JAK2
-positive patients with APS were subsequently diagnosed with MPN. In patients with JAK2
mutation, presence of concomitant APS was associated with a significantly younger age (49 ± 14 vs. 60 ± 15 years) at the time of thrombophilia work-up (p < 0.05).
We found a significant association between JAK2
-positive MPN and definite APS. The presence of concomitant APS in patients carrying the JAK2
mutation may lead to earlier manifestation of thromboembolic events and may warrant more aggressive antithrombotic treatment strategies to prevent recurrence.
▪
Background: Acquired hemophilia A (AHA) is a severe bleeding disorder that requires fast and accurate diagnosis as it occurs often unexpectedly in previously healthy men and women of every age. The ...Nijmegen-modified Bethesda assay (NBA) is the diagnostic gold standard detecting neutralizing anti-FVIII autoantibodies, but is not widely available, not ideal to quantify the complex type 2 inhibitors seen in AHA, and suffers from high inter-laboratory variability.
Objectives: To assess the diagnostic and prognostic value of FVIII binding antibodies as detected by a commercial ELISA (Hyphen Biomed/Coachrom) compared with the NBA.
Methods: Samples and clinical data were available from 102 patients with AHA enrolled in the prospective GTH-AH 01/2010 study. Controls were matched for gender and age. Diagnostic cut-offs were determined by receiver-operator curve (ROC) analysis on training and validation sets, assigned by 1:1 randomization, and by classification and regression tree (CRT) analysis. Prognostic value was assessed by Cox regression analysis of time to partial remission.
Results: Anti-FVIII IgG above the 99th percentile (>15 AU/ml) revealed high sensitivity (1.0, 95% confidence interval CI 0.92-1.0) and specificity (1.0, CI 0.92-1.0) to diagnose AHA. The likelihood of achieving remission was strongly related to antibody concentration (anti-FVIII IgG <100 AU/ml: 1.0; 100-<1000 AU/ml: 0.40; ≥1000 AU/ml: 0.21). This association was stronger than that between NBA inhibitor titer and likelihood of remission.
Conclusion: Although the NBA is the gold standard for demonstrating neutralizing antibodies in AHA, the detection of FVIII-binding antibodies by anti-FVIII IgG ELISA is similarly sensitive and specific to diagnose AHA. In addition, anti-FVIII IgG provides important prognostic information.
Tiede:CSL Behring: Consultancy, Honoraria, Research Funding; Baxter: Consultancy, Honoraria, Research Funding; Bayer: Consultancy, Honoraria, Investigator, Research Funding; Biotest: Consultancy, Honoraria, Research Funding; Leo Pharma: Consultancy, Honoraria; SOBI: Consultancy, Honoraria; Boehringer Ingelheim: Consultancy, Honoraria; Pfizer: Consultancy, Honoraria; Novo Nordisk: Consultancy, Honoraria, Research Funding; Biogen Idec: Consultancy, Honoraria; Coachrom: Research Funding; Octapharma: Other: Investigator, Speakers Bureau. Geisen:Roche Diagnostics International AG, Switzerland: Research Funding; Baxalta: Honoraria; Bayer: Research Funding; Novo Nordisk: Consultancy, Honoraria. Nowak-Göttl:Bayer: Consultancy; LFB: Consultancy; Octapharma: Consultancy. Eichler:CSL Behring: Consultancy, Research Funding; Biotest: Consultancy, Research Funding; Novo Nordisk: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Baxter: Consultancy, Research Funding; Bayer: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding. Klamroth:Bayer, Baxter, CSL Behring, Pfizer, Novo Nordisk, and Octapharma: Honoraria, Research Funding, Speakers Bureau; Biogen and SOBI: Honoraria, Speakers Bureau. Huth-Kühne:Biotest: Consultancy; Baxalta: Consultancy; CSL: Consultancy; Bayer: Consultancy.
Tissue factor (TF), the principal initiator of the extrinsic coagulation pathway, is expressed by many tumors and can be released into the bloodstream on plasma microparticles (MPs). Experimental ...studies indicate that TF may facilitate hematogenous metastasis by promoting tumor cell-induced microvascular thrombosis, but clinical data supporting this hypothesis is sparse.
Here, we report 2 unusual cases of rapidly progressive solid malignancies (gastric and urothelial carcinoma). In both patients, cancer cell dissemination with diffuse bone marrow involvement was either strongly suggested by leukoerythroblastic changes on peripheral blood smear or directly proven by positive findings on aspiration cytology. Furthermore, laboratory evidence of thrombotic microangiopathy (TMA) and disseminated intravascular coagulation was accompanied by new-onset severe pulmonary hypertension and a hemolytic uremic syndrome-like disorder in the gastric and the urothelial carcinoma patient, respectively. TF-specific procoagulant activity of isolated plasma MPs, as assessed by single-stage clotting assay, was dramatically increased in both patients compared to healthy controls (21- and 55-fold), and primary tumor samples stained strongly positive for TF by immunohistochemistry.
TMA was likely caused by TF-triggered tumor cell embolization in both patients. Further clinical evidence is thus provided that TF directly links coagulation activation to cancer cell dissemination.
Tissue factor (TF) expressed on sub-cellular membrane vesicles, so-called plasma microparticles (MPs), has recently emerged as a potential key player in intravascular coagulation activation in ...various disease states. In this report, we demonstrate significantly increased levels of TF-specific procoagulant activity (PCA) of plasma MPs in five patients presenting with overt disseminated intravascular coagulation (DIC) due to an underlying malignancy, including non-small-cell lung cancer (
n
= 1), melanoma (
n
= 1), prostate cancer (
n
= 2), and acute promyelocytic leukemia (
n
= 1). Clotting experiments on available tumor cell samples suggested that cancer cells were a potential source of circulating TF-positive MPs at least in three of the five patients. Furthermore, follow-up plasma samples from two surviving patients revealed that response of their malignancies to specific anti-cancer therapy was paralleled by resolution of overt DIC and a significant decline in MP-associated TF PCA. Levels of plasma TF antigen, as assessed by an enzyme-linked immunosorbent assay, were also increased at presentation albeit to a lesser extent compared to MP-associated TF PCA, likely due to insufficient solubilization of the phospholipid-incorporated full-length TF molecule by the detergent. In summary, our findings suggest that MP-associated TF PCA may play an important pathogenic role in the evolution of overt DIC in various types of malignancy.
Abstract 1074
Von Willebrand’s disease type 2B (VWD2B) is a rare bleeding disorder characterized by enhanced binding of von Willebrand factor (VWF) to platelet GPIbα due to gain-of-function mutations ...clustering in the VWF A1 domain. Binding of mutated type-2B VWF to GPIbα on circulating platelets may result in spontaneous platelet agglutination and increased ADAMTS13-mediated proteolysis of bound VWF. Consequently, thrombocytopenia, loss of larger VWF plasma multimers, and increased agonist-induced platelet agglutination at low concentrations of ristocetin are typical findings in VWD2B. However, not all of these laboratory features must be present, and confirming a diagnosis of VWD2B can thus be a challenge. We describe the case of a first-time pregnant woman (MCMDM-1 bleeding severity score, 10) with hereditary thrombocytopenia (platelet count, 17 × 109/L) and spontaneous ex-vivo platelet aggregate formation, in whom previous testing for VWD2B had been inconclusive due to absent additional platelet agglutination at low concentrations of ristocetin. Therefore, platelet-type VWD caused by mutated GPIbα remained possible. Microscopic examination of the patient’s peripheral blood smear revealed both small agglutinates of moderately enlarged and scattered single giant platelets. VWF:CB was 26% (normal, 50–250%), and VWF:Ag was 56% (50–160%), resulting in an abnormal activity to antigen ratio of 0.46 (0.8–1.2). Multimer analysis revealed loss of larger and intermediate sized VWF plasma multimers, and VWD2B was eventually diagnosed by identification of the mutation p.A1461D in the VWF A1 domain. Using an in-house ELISA, we assessed binding of recombinant wild-type (WT) and mutant VWF, respectively, to an immobilized GPIbα fragment in the absence and presence of increasing concentrations of ristocetin (0.3–1.5 mg/mL). Surprisingly, when compared to WT VWF in the presence of 1.5 mg/mL ristocetin (100%), binding of the p.A1461D mutant was already increased to 177% in the absence of ristocetin with only marginal additional binding evident at 1.5 mg/mL (238%). In comparison, binding of the p.V1316M mutant causative of VWD2B formerly described as the Montreal platelet syndrome, an inherited form of thrombocytopenia characterized by mucocutaneous bleeding and circulating giant platelets, was only 73% at 0 mg/mL ristocetin with significantly increased binding at 1.5 mg/mL (171%). Interestingly, ex-vivo stimulation of the patient’s platelets with ADP or TRAP-6 resulted in only minimal surface CD62P expression, as analyzed by flow cytometry, while no CD62P was present on un-stimulated platelets, suggesting defective α -granule secretion. Similar findings were obtained on platelets from the patient’s father and brother who also had severe thrombocytopenia and genetically confirmed VWD2B. Successful delivery of a healthy infant was achieved by only two peripartal doses of highly purified VWF concentrate in addition to systemic antifibrinolytics. In summary, this report further highlights the importance of genetic testing for the diagnostic work-up of suspected VWD2B, because the typical VWF activity pattern may not be present in all patients. Furthermore, our ELISA data demonstrate significant ristocetin-independent binding of the p.A1461D VWF mutant to platelet GPIbα, suggesting that the assay could be useful in differentiating VWD2B from platelet-type VWD in cases with severe thrombocytopenia and/or pronounced spontaneous platelet agglutination. Finally, our flow cytometry experiments support the concept of altered megakaryocytopoiesis and dysfunctional (pro)platelet production in VWD2B, which are likely due to adhesive intracellular interactions between mutated VWF and GPIbα and may result in concomitant α -storage pool disease.
No relevant conflicts of interest to declare.
Acquired hemophilia A (AHA) and acquired von Willebrand Syndrome (AVWS) are both rare bleeding disorders that can be associated with lymphoproliferative or autoimmune diseases. AHA is uniformly ...caused by inhibitory autoantibodies against coagulation factor VIII (FVIII), while the pathophysiology of AVWS comprises several distinct mechanisms, including reduced synthesis, accelerated clearance, or increased proteolysis. In this regard, autoantibodies to von Willebrand factor (VWF) have been described in patients with systemic lupus erythematosus (SLE) or monoclonal gammopathy. Here, we report the case of a 71-year-old patient with a recent onset of spontaneous mucocutaneous and soft-tissue bleeding due to severely decreased FVIII and VWF. While there was no evidence for monoclonal gammopathy, specific IgG antibodies against both FVIII and VWF were detected. Furthermore, VWF multimer analysis revealed the presence of ultralarge plasma multimers and absence of the typical multimeric triplet structure, a finding consistent with decreased proteolytic processing of massively released, but rapidly cleared VWF. Both FVIII and VWF readily responded to immunosuppressive therapy with prednisolone. Interestingly, clinical and laboratory findings established the diagnosis of "late-onset SLE" in our patient. Thus, about 45 years after the first description of AVWS in a 12-year-old boy with SLE, we present another unusual case of concomitant autoimmune-mediated AHA and AVWS in an elderly SLE patient, which, to the best of our knowledge, has not been reported so far.
The management of patients with acquired factor V inhibitors is challenging, because their bleeding risk is highly variable and only poorly correlated with routine coagulation tests. Furthermore, ...there is no standardized treatment for bleeding control or inhibitor eradication. An 84-year-old white man underwent uneventful surgery for a ruptured intracerebral haemangioma. There were no perioperative coagulation abnormalities. Eight weeks after surgery, however, the prothrombin and the activated partial thromboplastin times were found to be maximally prolonged without signs of acute haemorrhage. A factor V inhibitor of 212 Bethesda units was diagnosed. We used a fluorogenic real-time thrombin generation assay with low concentrations of tissue factor (TF) to analyse the factor V inhibitor for interference with coagulation in platelet-poor plasma. Compared with three bleeding patients with acquired haemophilia A and severely deficient thrombin generation, total thrombin generation capacity was similar in the patient and healthy controls. However, the lag phase was significantly prolonged, suggesting a defect in the initiation/amplification, but not in the propagation phase of TF-triggered thrombin generation. This defect could be fully reproduced by purified patient IgG and largely corrected by ex-vivo addition of activated prothrombin complex concentrate, but not recombinant human FVIIa. Addition of normal platelets to the patientʼs plasma resulted in a pronounced shortening of the lag phase, suggesting that platelet-derived factor V can escape the inhibitor. Our findings offer an explanation for the absence of spontaneous bleeding in this patient and support the concept of platelet transfusions for the management of acute haemorrhages in patients with acquired factor V inhibitors.
Abstract 1132
The main purpose of this prospective, multi-center, open-label phase 3 study was to assess the efficacy of prophylactic treatment with Human-cl rhFVIII, the first human cell-line ...derived recombinant FVIII, in previously treated patients (PTPs) with severe haemophilia A.
Patients were to receive 30–40 international units (IU) FVIII of Human-cl rhFVIII per kg every other day for 6 months. Efficacy of preventing and treating bleeds were judged using objective criteria taking the monthly bleeding rate and the number of infusions needed to manage a break-through bleed into account. In-vivo recovery (IVR) was determined at the beginning of the study and after 3 and 6 months. FVIII:C was measured by validated chromogenic (CHR) and one-stage (OS) assays in a central laboratory, which also assigned drug potencies. Inhibitor activity was determined using the Nijmegen modification of the Bethesda assay before the first administration and at defined intervals thereafter. Thirty-two patients between 18 and 75 years of age were enrolled from 11 centres in Europe and treated prophylactically for 6.0±0.9 months (mean ± SD) with a mean prophylactic dose of 32.8 IU/kg. Sixteen patients never bled, 11 patients bled once and 5 more than once. The mean total and spontaneous monthly bleeding rate was 0.188±0.307 and 0.095±0.211, respectively. Efficacy of the prophylactic treatment was “excellent” in all patients for spontaneous BEs and “excellent” or “good” in all patients but one for all types of bleeds. All treatments of bleeds were rated as “excellent” (71.4%) or “good” (28.6%). The IVR at baseline was 2.6±0.5 % per IU/kg for the CHR and 2.2±0.5 % per IU/kg for the OS assay and remained stable during the study. A total of 2921 infusions were given in the study. Human-cl rhFVIII was well tolerated and no patient experienced a related serious adverse event. No FVIII inhibitors were detected.
The data indicate that Human-cl rh FVIII is safe and efficacious in preventing and treating bleeds in PTPs with severe haemophlia A.
Knaub:Octapharma AG: Employment. Lissitchkov:Octapharma AG: PI Other. Tuddenham:College London: Consultancy, Employment, Gene therapy for hemophilia A, Gene therapy for hemophilia A Patents & Royalties, Research Funding. Collins:Octapharma AG: Consultancy. Oldenburg:d and e: Baxter, Bayer, Biotest, CSL-Behring, Grifols, Inspiration, NovoNordisk, Octapharma, Pfizer e: Biogen IDec, Swedish Orphan Biovitrum: Honoraria, Research Funding. Bichler:Octapharma AG: Employment.
Acquired hemophilia A (AHA) is a rare autoimmune disorder caused by neutralizing autoantibodies against coagulation factor VIII (FVIII:C). Immunosuppressive treatment may result in remission of ...disease over a period of days to months. Until remission, patients are at high risk of bleeding and complications from immunosuppression. Prognostic parameters to predict remission and the time needed to achieve remission could be helpful to guide treatment intensity, but have not been established so far. GTH-AH01/2010 was a prospective multicenter cohort study using a standardized immunosuppressive treatment protocol. The primary study endpoint was time to achieve partial remission (PR, defined as FVIII:C activity >50 IU/dl after cessation of any hemotherapy for >24h, and no active bleeding). Secondary endpoints were time to achieve complete remission (CR, defined as PR plus negative FVIII:C inhibitor, steroid tapered to <15 mg/d prednisolone, and cessation of any other immunosuppressive treatment), and overall survival (OS). Enrolment was strictly prospective and only allowed within 7 days of starting immunosuppression. Outcome data were recorded in all patients enrolled. The treatment protocol consisted of prednisolone (100 mg/d from day 1 to the day of PR, then tapered down to <15 mg/d over 5 weeks), oral cyclophosphamide (150 mg/d, from day 21-42, unless PR was achieved), and rituximab (375 mg/m2 weekly for 4 weeks starting on day 43, unless PR was achieved). If AHA was first diagnosed in patients previously on prednisolone >15 mg/d, or equivalent, they received prednisolone (100 mg/d) and rituximab from day 1. If cyclophosphamide was contraindicated, patients received prednisolone (100 mg/d) and rituximab from day 21. One hundred twenty-four patients from 21 treatment centers in Germany and Austria were enrolled between April 2010 and April 2013 (36 months). The patients from two centers not compliant with the treatment protocol were excluded (N=18), as were patients in whom AHA was not confirmed (N=2) or follow-up was too short at the time of this analysis (N=7). The remaining 97 patients from 17 centers were followed for a median of 256 days (interquartile range IQR 84-561). Median age was 74 years (IQR 64-82). AHA was associated with other autoimmune disorders (19%), malignancy (12%), pregnancy or puerperium (5%), but was most often idiopathic (66%). The median FVIII:C activity at baseline was 1 IU/dl (IQR <1-3), and the median inhibitor titer was 20 BU/ml (IQR 7.7-78). PR and CR were achieved after a median time of 35 and 102 days, respectively. Patients achieving PR prior to day 21 (N=22) compared with patients not achieving PR within 21 days (N=75) had a higher baseline FVIII:C activity (median 3 vs. <1 IU/dl, p<0.01) and a lower FVIII:C inhibitor (median 12 vs. 29 BU/ml, p<0.05). Multivariate analysis with adjustment for age, sex, underlying disorder, and WHO performance status on admission demonstrated that baseline FVIII:C activity (<1 IU/dl vs. >=1 IU/dl) had a strong impact on the time to achieve PR (HR 2.76 95% confidence interval 1.73-4.42, p<0.001) and CR (HR 2.36 1.34-4.14, p<0.01). Baseline FVIII:C activity was also a predictor of PR and CR when other cutoffs were used (2 or 3 IU/dl instead of 1 IU/dl), or when it was analyzed as a continuous variable in Cox regression analysis. In contrast, FVIII:C inhibitor titer assessed by the local laboratory did not affect time to PR or CR significantly. OS after 300 days, estimated by the Kaplan Meier method, was 69%. Age, WHO performance status, and FVIII:C activity at baseline were independent predictors of OS. In summary, GTH-AH 01/2010 is the largest prospective study of patients with AHA treated according to a standardized protocol. The study demonstrated a robust effect of baseline FVIII:C activity on the time needed to achieve PR and CR. Baseline FVIII:C activity, together with age and performance status, also affected OS. Therefore, baseline FVIII:C activity may be considered to guide individually tailored immunosuppression in future studies.
Tiede:Baxter: Consultancy, Honoraria, Research Funding; Bayer: Consultancy, Honoraria, Research Funding; Biotest: Consultancy, Honoraria, Research Funding; Pfizer: Consultancy, Honoraria, Research Funding; Novo Nordisk: Consultancy, Honoraria, Research Funding; Biogen Idec: Consultancy; CSL Behring: Consultancy, Honoraria, Research Funding. Off Label Use: Prednisolone, cyclophosphamid, and rituximab for immunosuppression in acquired hemophilia. Klamroth:Bayer: Honoraria, Research Funding; Baxter: Honoraria, Research Funding; CSL Behring: Honoraria, Research Funding; Novo Nordisk: Honoraria, Research Funding. Gottstein:Novo Nordisk: Honoraria; Baxter: Honoraria. Holstein:Baxter: Honoraria, Speakers Bureau. Scharf:CSL Behring: Consultancy, Honoraria, Research Funding; Pfizer: Consultancy, Honoraria; Biotest: Consultancy, Honoraria, Research Funding; Bayer: Consultancy, Honoraria; Baxter: Consultancy, Honoraria, Research Funding. Huth-Kühne:SRH Kurpfalz Hospital and Hemophilia Center: Consultancy, Employment, Honoraria, Membership on an entity's Board of Directors or advisory committees. Greil:Roche: Consultancy, Honoraria, Research Funding. Miesbach:Novo Nordisk: Consultancy, Honoraria, Research Funding; Baxter: Consultancy, Honoraria, Research Funding. Trappe:Roche: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau, Travel Other; AMGEN: Research Funding, Travel, Travel Other; CSL Behring: Honoraria, Research Funding, Speakers Bureau, Travel, Travel Other; Mundipharma: Research Funding, Travel, Travel Other; Takeda: Consultancy, Research Funding, Travel Other; Novartis: Consultancy, Research Funding, Travel, Travel Other; Novartis: Research Funding, Travel Other; Cellgen: Travel, Travel Other. Knoebl:Novo Nordisk: Consultancy, Honoraria; Baxter: Consultancy, Honoraria.
PDF
