How mild is mild haemophilia?

INTRODUCTION: People with mild haemophilia (PWMH) experience sporadic bleeds and are less likely to receive an early diagnosis, appropriate treatment and medical care. Arthropathy is a key determinant of health-related quality of life (QoL), producing pain, limitations in mobility and daily activities. The aim of this study is to evaluate the incidence, risk factors and QoL associated with arthropathy in PWMH. MATERIALS AND METHODS: Observational, cross-sectional cohort study. Data were collected in a single interview and evaluated by a physiotherapist and an orthopaedist and analysed on demographics; baseline factor levels; as well as clinical (Haemophilia Joint Health Score [HJHS]), ultrasound (Haemophilia Early Arthropathy Detection with Ultrasound [HEAD-US]), radiological (Pettersson score [PS]), pain (visual analogue scale [VAS]) and QoL evaluations. We defined arthropathy when at least one of the joints shown with a HEAD-US score ≥ 1. RESULTS: Eighty-five patients and 510 joints were included. Patients' mean age was 35.9 years-old. Median age was 44.2 in patients with arthropathy versus 14.9 in patients without; the difference was statistically significant (p < .001). In patients over 20 years old, 90.5% shown arthropathy. Only 24 (28%) patients had no joint damage (HEAD-US = 0), and 61 (72%) had at least one joint with a HEAD-US ≥ 1. The ankle was the most affected joint. Patient age was found to be the most important risk factor associated with the development of arthropathy. CONCLUSIONS: Joint damage as a result of prior hemarthrosis was the most relevant factor associated with lower QoL, and emphasised the importance of early diagnosis and appropriate management in this particular population.

Anticuerpos anti-FVIII: su evaluación por citometría de flujo / Anti FVIII antibodies: evaluation by flow cytometry

En este trabajo se describe un sistema para evaluar y caracterizar los anticuerpos anti-FVIII en pacientes con Hemofilia A Severa (HAS) que reciben el Factor como tratamiento de sustitución. Consiste en el empleo combinado de microesferas y Citometria de Flujo (CF). El rFVIII fue acoplado a microesferas de 2 µm de diámetro (m-FVIII) las cuales se incubaron con diluciones de plasma o suero de pacientes con (n=13) o sin (n=17) inhibidor, pacientes en Tratamiento Inmunotolerante (TIT)(n=5) y dadores normales (N) (n=12). Los anticuerpos se revelaron con anti-lgG humana, anti-lgG1, anti-lgG2, anti-IgG3 o anti-lgG4 biotiniladas, seguido por streptavidina-ficoeritrina. Se registraron los valores de Intensidad de Fluorescencia Media (IFM). Microesferas sin FVIII (m-Control) se utilizaron como control. El resultado se expresó como índice: (IFM de m-FVIII/IFM de m-Control) multiplicado por la inversa de la dilución de máxima respuesta. Se determinó el porcentaje de contribución de cada subclase de IgG. Los resultados presentaron un 86 por ciento de concordancia con la prueba de Bethesda y un 80 por ciento con ELISA. El método fue útil para el seguimiento de los pacientes durante el TIT. La IgG4 prevaleció en pacientes con alto título y al comienzo del TIT. La CF es fácil y rápida y requiere sólo 200 µl de muestra.

In this study, a Flow Cytometry (FC) system is described for detecting and characterizing antibodies (inhibitors) to Factor VIII (FVIII) in Severe Haemophilia A (SHA) patients following FVIII infusion. A combination of microspheres and Flow Cytometry (FC) was employed. First, rFVIII was coupled to microspheres of 2 µm of diameter (m-FVIII). Then, they were reacted with dilutions of plasma or serum of patients with (n=13) or without (n=17) inhibitors. Five patients receiving Immunotolerant Treatment (ITI) and 12 normal donors were included. Microspheres without rFVIII were used as control (m-Control). Captured anti-FVIII antibodies were detected using biotinylated anti-Human IgG, IgG1, IgG2, IgG3 or IgG4 followed by streptavidin-phycoerythrin. FC analysis was performed recording Mean Fluorescence Intensity (MFI). Results were given as an Index: the highest MFI ratio between m-FVIII and m-Control multiplied by the inverse of the corresponding plasma dilution. The contribution of each IgG subclass was expressed as percentage. FC results had 86 per cent and 80 per cent of coincidence with the Bethesda method and ELISA respectively. The test was useful to measure anti-FVIII antibodies during the ITI. IgG4 was the prevalent IgG subclass in patients with high level of inhibitors and previously to ITI. FC was easy, fast and requires only 200 µl of sample.

Prevalencia de anticuerpos neutralizantes y no neutralizantes en personas con hemofilia en Argentina / Prevalenceof neutralizing antibodies and not in people with henophilia in Argentina

El desarrollo de inhibidores (1nh) o anticuerpos neu-ralizantes (Ac Ntr) es una de las complicaciones del tratamiento de personas con hemofilia (PCH). Los Ac Ntr actúan inhibiendo la actividad coagulante del FVIII/IX. Se conoce la existencia de Ac anti FVIII no neutralizantes (Ac no Ntr), con posible influencia en la vida media del FV111 transfundido. Los Ac Ntr se detectan en ellaboratorio en ensayos coagulométricos y se cuantifican por método Bethesda o Nijmegen. Los Ac no Ntr sólo pueden detectase en ensayos inmunológicos. Con el objeto de determinar la prevalencia de Ac Ntr y no Ntr estudiamos 801 muestras de PCH. La detección de Ac anti FV111 se realizó mediante una técnica de ELISA y los resultados positivos fueron confirmados por método Bethesda modificado o Nijmegen para obtener el título de Ac Ntr. En PCH B se realizó la titulación del inh por método Bethesda. La prevalencia de Ac Ntr en la población estudiada fue de 14.7% en hemofilia A y 5.0% en hemofilia B. Encontramos una baja prevalencia de Ac no Ntr (3.3%) en hemofilia A. Estos pacientes serán evaluados con mayor frecuencia dado el alto riesgo de desarrollar Ac Ntr en el futuroEl desarrollo de inhibidores (inh) o anticuerpos neutralizantes (Ac Ntr) es una de las complicaciones del tratamiento de personas con hemofilia (PCH). La Ac Ntr actúan inhibiendo la actividad coagulante.