Factores predictores de respuesta a los tratamientos de inmunotolerancia en pacientes hemofílicos A con inhibidores

En el momento actual se considera que la aparición de inhibidores tras la administración de concentrados del factor deficitario es la complicación más seria y que condiciona en mayor medida el tratamiento y la calidad de vida de los hemofílicos. Este problema es mucho más frecuente en hemofilia A grave (21-33%). El objetivo terapéutico a largo plazo es la erradicación del inhibidor mediante los tratamientos de inducción de tolerancia inmunológica (ITI). En este trabajo se presentan los resultados de los ITI llevados a cabo en una unidad de referencia en coagulopatías. Se trata de un estudio retrospectivo y prospectivo de los tratamientos efectuados entre 1980 y 2015. En este periodo se trataron 26 pacientes, 3 de los cuales todavía están en tratamiento. El análisis estadístico se ha efectuado con los 23 pacientes que terminaron la primera línea de ITI. Se ha realizado el análisis descriptivo y un modelo de regresión logística con penalización L1 (LASSO). La mediana de edad en el momento de iniciar el ITI es de 2 años (Q1,Q3: 1, 3). El valor de la mediana para los diferentes títulos de inhibidor es: histórico máximo, 22 UB/mL (Q1,Q3: 10, 100); pre ITI 4,6 UB/mL (Q1,Q3: 2, 8,75); durante el ITI 23,7 UB (Q1,Q3: 2,83, 210). La mediana de tiempo de tratamiento en los pacientes que responden es de 11,7 meses (Q1,Q3: 9,77, 27,66). En cuanto al tipo de factor: 14/23 pacientes utilizaron concentrados de FVIII de origen plasmático (pdFVIII), 13 de ellos el factor plasmático era rico en Factor von Willebrand (FVW); 9 pacientes se trataron con concentrado de origen recombinante. En cuanto a la dosis: en 17/23 pacientes se utilizó una dosis 100 UI/kg/día. Se consideró éxito cuando el inhibidor fue negativo y además, la recuperación y la vida media del FVIII infundido fue normal. La tasa de éxito con las primeras líneas de ITI es del 57%. Hay dos variables que influyen en el éxito: a) un menor título máximo de inhibidor durante el ITI y b) la utilización de pdFVIII para efectuar el ITI. En el análisis estadístico la utilización de pdFVIII con FVW aporta una parte pequeña, pero no podemos discriminar el poder de esta variable, por las características de nuestra serie. No tienen significación estadística influyendo en el éxito: el tipo de mutación, el título máximo histórico de inhibidor, el título de inhibidor pre ITI, la edad al ITI, la demora en empezar el ITI, la dosis de FVIII empleada, la utilización de accesos venosos centrales ni la infección de éstos. La tasa de respuesta es del 85,7% cuando se consideran los tratamientos de rescate junto con los de primera línea, incluyendo los dos pacientes con cambios de inmunorrespuesta. La tasa de recidiva después de un periodo de seguimiento de 9,12 años (Q1,Q3: 3,98, 13,40) es del 11%. En hemofílicos con inhibidores en edad pediátrica, es importante insistir en la erradicación del inhibidor, dada la larga expectativa de vida en este grupo poblacional.The development of neutralizing anti factor VIII (FVIII) antibodies is the major complication in the treatment of haemophilia A patients with FVIII products. This complication, conditions further treatment and quality of life of haemophiliacs. This problem is much more common in severe haemophilia A (21-33%). The therapeutic long-term goal is the eradication of the inhibitor by treatments of immune tolerance induction (ITI). In this work we present the results of ITI carried out in a haemophilia reference unit. It is a mixed retrospective and prospective study. The treatments were carried out between 1980-2015. During this period 26 patients were treated, 3 of whom are still in treatment. Statistical analysis was performed with the 23 patients who completed the first line of ITI. It has been performed descriptive analysis and logistic regression with penalty L1 (LASSO). The median age at the ITI start is 2 years (Q1; Q3: 1; 3). The median historical pick inhibitor titre was, 22 BU/mL (Q1; Q3: 10;100); pre ITI 4,6 BU/mL (Q1; Q3: 2; 8,75); pick inhibitor during ITI 23,7 BU/mL (Q1; Q3: 2,83; 210). The median treatment duration in successful patients was 11,7 months (Q1; Q3: 9,77; 27,66). As for the type of factor: 14/23 patients used plasma FVIII concentrates (pdFVIII), 13 of them was rich in von Willebrand factor (VWF); 9 patients were treated with recombinant concentrates. Dosage regimens used were: 100 IU/kg/day in 4/23. It was considered successful when the inhibitor was negative and also normal recovery and half-life of FVIII infused. Success rate with the first lines of ITI was 57%. A statistically significant associations was observed for a lower maximum inhibitor titre during ITI and the use of pdFVIII in the ITI. In the statistical analysis, pdFVIII with VWF contributes a small part, but we can not discriminating power of this variable by the nature of our series. No statistically significant association with: the type of mutation, the historical pick inhibitor titre, the titre at ITI start, age at ITI, the delay in start ITI, FVIII dose employed, the use of access central venous and the infection of these. Complete success rate was 85.7% when were considered the success in rescue treatments and the first line, including the two patients with immune changes. The rate of relapse after a period of 9,12 years follow-up (Q1; Q3: 3,98;13,40) was 11%. In haemophiliacs with inhibitors in paediatric age, it is important to stress in the eradication of the inhibitor, given the long life expectancy in this group population

Association of the 3467C>T mutation (T1156M) in the von Willebrands factor gene with dominant type 1 von Willebrands disease

[EN] Type I is the most frequent form of von Willebrand's disease, which is characterized by a quantitative partial deficiency of von Willebrand's factor. At present, only two mutations located in the D3 domain (C1149R, C1130F) have been reported to cause the classic type I variant. The 3467C>T transition that predicts the T1156M amino acid change was detected in seven patients from one family and was not found in 110 normal alleles screened. This is a candidate mutation to cause dominant type I variant with complete penetrance. On the other hand, neither of the two mutations mentioned above has been detected in the other 15 families studied with type I or possible type 1 patients.This work was supported in part by grant #99/0633 (FIS, Spain). We wish to thank R. Curats and J.M. Montoro for their technical assistance and Mr. Peter Blair for his linguistic advice.Casaña-Gargallo, MP.; Francisco Martínez; Saturnino Haya; Espinós-Armero, CÁ.; José Antonio Aznar (2001). Association of the 3467C>T mutation (T1156M) in the von Willebrands factor gene with dominant type 1 von Willebrands disease. Annals of Hematology. 80(7):381-383. https://doi.org/10.1007/s00277010030738138380

Significant linkage and non-linkage of type 1 von Willebrand Disease to the von Willebrand factor gene

[EN] Significant linkage of types 2A and 2B von Willebrand disease (VWD) to the von Willebrand factor (VWF) gene have been reported, as well as mutations in the VWF gene. However, data for the partial quantitative variant are less consistent. An inconsistency of association between the type 1 VWD phenotype and genotype has been reported recently. We undertook linkage analysis of 12 families with definite or possible type 1 VWD patients. One family with classic type 1 VWD had a high lod score (Z = 5.28, theta = 0.00). A total lod score of 10.68 was obtained for the four families with fully penetrant disease. In two families linkage was rejected, while three families did not show conclusive evidence of linkage. This study corroborates ABO blood group influence, especially in patients with mild deficiencies and/or incomplete penetrance, Indirect genetic analysis may be an option for diagnosing asymptomatic or presymptomatic type 1 VWD carriers, particularly in families showing higher penetrance. The study indicates defects of the VWF locus are to be expected in more than half of the families studied. However, as defects at different loci may be the cause of this phenotype, the results of the segregation analyses should be interpreted with caution, especially in studies involving small families, or mild expressions of the disorder or incomplete penetrance.This work was partly supported by F1S grant # 99/0633 (Spain). We wish to thank J. M. Montoro for the multimeric structure analyses, R. Curats for his help in the segregation analyses, all the staff of the `Unidad de CoagulopatõÂas CongeÂnitas de la Comunidad 5alenciana' for their technical and clinical assistance, and Mr Peter Blair for the linguistic advice given in writing this paper.Casaña-Gargallo, MP.; Martínez, F.; Haya, S.; Espinós-Armero, CÁ.; Aznar, JA. (2001). Significant linkage and non-linkage of type 1 von Willebrand Disease to the von Willebrand factor gene. British Journal of Haematology. 115(3):692-700. https://doi.org/10.1046/j.1365-2141.2001.03132.x692700115

Search for Mutations in a Segment of the Exon 28 of the Human Von Willebrand Factor Gene. New Mutations, R1315C and R1341W, Associated with Type 2M and 2B Variants

[EN] von Willebrand Disease (vWD) is the most frequently inherited bleeding disorder in humans, and is caused by a qualitative and/or quantitative abnormality of the von Willebrand factor (vWF), A large number of defects that cause qualitative variants have been located in the Al domain of the vWF, which contains sites for interaction with platelet glycoprotein Ib (GPIb). We have developed a new approach to detect mutations based on Ddel digestion and single-strand conformation polymorphism analysis. A segment of 487 nucleotides, extending from intron 27 to codon 1368 of the pre-pro vWF was amplified from genomic DNA, The cleavage with Ddel yields two fragments of appropriate size for this kind of analysis and confirms that the gene, rather than the pseudogene, is being investigated, Six families with type 2B vWD: one type 2M vWD family, and one another type 2A vWD family were studied. After sequencing the fragments with an altered electrophoretic pattern, we found four mutations previously described-R1308C, V1316M, P1337L, and R1306W-in patients with 2B vWD, The last one arose de novo in the patient. In addition, two new candidate mutations were observed: R1315C and R1341W. The first one was associated to type 2M vWD, whereas the one second cosegregated with type 2B vWD. The fact that these new mutations were not found in 100 normal alleles screened further supports their causal relationship with the disease, These mutations, which induce either a gain or a loss of function, further show an important regulatory role of this region in the binding of vWF to GPIb and its implications in causing disease.We wish to thank J.M. Montoro for performing multimeric assays and R. Curats for his technical assistance.Casaña, P.; Martínez, F.; Espinós-Armero, CÁ.; Haya, S.; Lorenzo, JI.; Aznar, JA. (1998). Search for Mutations in a Segment of the Exon 28 of the Human Von Willebrand Factor Gene. New Mutations, R1315C and R1341W, Associated with Type 2M and 2B Variants. American Journal of Hematology. 59(1):57-63. https://doi.org/10.1002/(sici)1096-8652(199809)59:13.0.co;2-z576359

Q1311X: a novel nonsense mutation of putative ancient origin in the von Willebrand factor gene

[EN] Type 3 von Willebrand disease, a recessive autosomally inherited bleeding disorder, refers to complete deficiency of von Willebrand factor (VWF). The novel Q1311X mutation was detected in the homozygous state in four Spanish patients from two apparently unrelated families of gypsy origin. The lack of specific amplification of platelet VWF cDNA from two of the patients indicates reduced levels of mutated gene expression. The similar haplotype linked to mutated alleles suggests a common origin. On the basis of the two instabilities observed and the estimated mutation rate of the microsatellites of intron 40 of the VWF gene, we can estimate that this mutation could have arisen about 2300 years ago.We wish to thank J.M. Montoro and R. Curats for their technical assistance. This work was supported in part by F1S 99/0633.Casaña, P.; Martínez, F.; Haya, S.; Lorenzo, JI.; Espinós-Armero, CÁ.; Aznar, JA. (2000). Q1311X: a novel nonsense mutation of putative ancient origin in the von Willebrand factor gene. British Journal of Haematology. 111(2):552-555. https://doi.org/10.1046/j.1365-2141.2000.02410.x552555111

Emicizumab-induced photosensitivity

Emicizumab constitutes a novel and effective prophylaxis for hemophilia A patients with and without inhibitors. In this case report, we describe an emicizumab-induced photosensitivity that forced permanent sun-exposure suppression. To the best of our knowledge, this side effect had not been communicated until present

Severe and moderate hemophilia A: identification of 38 new genetic alterations

[EN] Hemophilia A is an X-linked recessive disorder caused by a lack or decrease of factor VIII activity. Its socio-economic impact is high given its high bleeding expression and treatment cost. Our aim was to establish the mutation of each patient to improve family management. A total of 116 unrelated families with severe and moderate hemophilia A were involved. Non-carriers of intron 22 and intron 1 rearrangements were included in F8 gene screening. Intron 1 and 22 inversion frequencies were 3% and 52.5% respectively. Putative mutations were identified in all the families; 38 were new, The cumulative inhibitor incidence was 22%. Approximately half the families carry non-recurrent mutations, which were unique in around one third. Harmful effects for mutations predicting null alleles are expected. Missense mutation consequences are not easily predictable, despite the help of some bio-informatics tools.this work was partly supported by FIS grant PI020612 (Spain) and by CSL Behring. We wish to thank all the staff of the 'Unidad de Coagulopatías Congénitas de la Comunidad Valenciana' for their technical and clinical assistance, and Helen Warburton for checking the English. Furthermore, the hematologists from the following hospitals for referring patients: Virgen de la Arrixaca (Murcia), San Pedro Alcántara (Cáceres), Torrecardenas and La Inmaculada (Almería), Marqués Valdecilla (Santander), and Pontificia Universidad Católica (Santiago de Chile).Casaña, P.; Cabrera, N.; Cid, AR.; Haya, S.; Beneyto, M.; Espinós-Armero, CÁ.; Cortina, V.... (2008). Severe and moderate hemophilia A: identification of 38 new genetic alterations. Haematologica. 93(7):1091-1094. https://doi.org/10.3324/haematol.123441091109493

Management of acquired hemophilia A: results from the Spanish registry

The Spanish Acquired Hemophilia A (AHA) Registry is intended to update the status of AHA in Spain. One hundred and fifty-four patients were included and retrospectively followed for a median of 12 months. Patients were predominantly male (56.3%), with median age at diagnosis of 74 years. AHA was more frequently idiopathic (44.1%) and autoimmune disorder-associated (31.7%). Thirty-four percent of patients were on antithrombotic therapy at diagnosis. Hemostatic treatment was used in 70% of patients. Recombinant activated factor VII was more frequently infused (60.3% vs 20.6% activated prothrombin complex concentrate). Only 1 patient did not achieve control of hemorrhage. Complete remission (CR) was achieved by 84.2% of cases after immunosuppressive therapy. Steroids alone were less efficient than the other strategies (68.2% vs 87.2%, P = .049), whereas no differences existed among these (steroids/cyclophosphamide, 88.5%, vs steroids/calcineurin inhibitors, 81.2%, vs rituximab-based regimens, 87.5%). Female sex and high inhibitor levels influenced CR negatively. Thirty-six deaths (23.8%) were reported. Main causes of death were infection (15 patients, 9.9%) and hemorrhage (5 patients, 3.3%). All hemorrhage-related and half the infection-related deaths occurred within 2 months of diagnosis. Prior antithrombotic therapy was inversely associated with survival, irrespective of age. Median age of nonsurvivors was significantly higher (79 vs 73 years in survivors). Patients dying of infection were older than the other nonsurvivors (85 vs 78 years). In summary, fatal infection in the first months is common in our series. Antithrombotic therapy is associated with mortality. Particular care should be taken to avoid misdiagnosis

Le Paysan de Cochinchine... Hebdomadaire de soutien des intérêts agricoles ["puis" Hebdomadaire français]

22 février 19401940/02/22 (N246)-1940/02/22

Von Willebrand Factor antigen and age explain variation in baseline FVIII:C among nonsevere hemophilia A patients with the same F8 genotype (Arg593Cys and Asn618Ser)

Introduction and Objectives: Non-severe hemophilia A (baseline FVIII:C, 2-40 IU/dL) is caused by a mutation in the F8 gene. There is limited knowledge on the factors determining the variation in baseline FVIII:C. The aim is to identify the determinants of baseline FVIII:C in non-severe hemophilia A patients. Materials and Methods: We analyzed clinical data for non-severe hemophilia A patients, treated between 1980-2013, in European Haemophilia Treatment Centers (HTCs) participating in the INSIGHT/RISE project. We performed analyses on mutations that were present in ≥10 patients. Age (at FVIII:C measurement), F8 gene mutation, VWF:Ag, VWF:Act and HTC were analyzed as potential determinants by multivariate regression analyses. Results: We identified nine missense mutations present in ≥10 patients in 321 individuals, median age 23 years (IQR 7-47). From these individuals we had data on 667 FVIII:C measurements in 5 HTCs. Median baseline FVIII:C, VWF:Ag and VWF: Act were 17 IU/dL (IQR 11-22), 98 IU/dL (IQR 78-128) and 91 IU/dL (70-115) respectively. Baseline FVIII:C, VWF:Ag and VWF:Act all increased with age, both in the total population and within the two largest mutation groups (Asn618Ser, 113 patients; Arg593Cys, 107 patients). VWF:Ag, age and F8 mutation were significant predictors of baseline FVIII:C (p <0.0001-0.024). In mutations that were present in ≥10 patients the determinants age, F8 mutation, VWF:Ag and HTC together explained 61% of the variation in baseline FVIII:C. Within the specific mutation group Asn618Ser only 21% of the variance in baseline FVIII:C was explained by the combined potential determinants, with VWF:Ag and HTC as significant predictors (p = 0.008 and 0.013 respectively). Among individuals with the Arg593Cys F8 genotype the determinants age, VWF:Ag and HTC were significant predictors (p <0.0001 for age and VWF:Ag and p = 0.04 for HTC), together explaining 34% of the variance in baseline FVIII:C. Conclusion: In non-severe hemophilia A patients carrying the same F8 mutation the determinants age, VWF:Ag and HTC contribute to baseline FVIII:C to variable extends. With the studied determinants we can only explain 61% of the variance in baseline FVIII:C. This suggests that yet unknown factors influence FVIII:C in nonsevere hemophilia A