title: Prevalence of inhibitor formation in a cohort of haemophilic children exposed to several products of various purities.
abstract: To evaluate the frequency and potency of inhibitor formation based on the product used, we retrospectively reviewed the records of 99 children with various types and severity of haemophilia (haemophilia A 82, severe 46; haemophilia B 10, severe 6; vWD 7) treated for the last 20 years. After a mean observation period of 8 years an overall of 23 patients (23.2'/0) developed an inhibitor (haernophilia A 26.8%; severe 4O%, moderate 20%, mild 3.8%). None of the haemophilia B patients presented with an inhibitor, and only one child with bevere vWD (1/7, 14.3%) showed a transient inhibitor under cryoprecipitate therapy. Inhibitor titre was low (< 5 BU) in most cases (91.3%) and in only two patients (8.75%) was 6 and 8 BU respectively. Antibodies to FVIII were transient (detected only once) in four (17.4%) and intermittent in 19 patients (82.6%). By the age of 12 years, 17/23 patients (73.9%) had demonstrated an inhibitor. The inhibitor detection seemed to be higher in the groups of patients exposed to monoclonal (3115, 20%), SID-treated (10159, 16.9%) or H/T FVIII concentrates (6/41, 14.6%), compared to groups of patients who received cryo/plasma (9.5%) or unmodified concentrates (5.1%); nevertheless the differences were not statistically significant. Surprisingly, none of the 52 patients who received a S/D + chromatography-treated factor VIIl concentrate developed an inhibitor after a mean observation period of 1.7 years (range 0.2-2 years). The overall prevalence of inhibitor formation in previously untreated haemophiliacs was 14.3% (4/28), irrespective of the product used. Our data indicate that a high proportion of our haemophilic children exposed to several products of various purities have developed a low-titre inhibitor which in most cases was transient or intermittent. However, despite the presence of the antibody, none of the patients needed a change in the mode of treatment.
authors.affiliation: Haemophilia and Haemostasis Unit, 'Aghia sophia' Children's Hospital, Athens, Greece.
authors.forename: S
authors.initials: S
authors.lastname: Aronis
authors.affiliation: Haemophilia and Haemostasis Unit, 'Aghia sophia' Children's Hospital, Athens, Greece.
authors.forename: H
authors.initials: H
authors.lastname: Platokouki
authors.affiliation: Haemophilia and Haemostasis Unit, 'Aghia sophia' Children's Hospital, Athens, Greece.
authors.forename: Z
authors.initials: Z
authors.lastname: Kapsimali
authors.affiliation: Haemophilia and Haemostasis Unit, 'Aghia sophia' Children's Hospital, Athens, Greece.
authors.forename: E
authors.initials: E
authors.lastname: Adamtziki
authors.affiliation: Haemophilia and Haemostasis Unit, 'Aghia sophia' Children's Hospital, Athens, Greece.
authors.forename: A
authors.initials: A
authors.lastname: Kolokithas
authors.affiliation: Haemophilia and Haemostasis Unit, 'Aghia sophia' Children's Hospital, Athens, Greece.
authors.forename: A
authors.initials: A
authors.lastname: Mitsika
keywords: Keywords:; children; haemophilia; inhibitors; therapy.