Haema 2010; 1(2): 163-171
by Eftichia Stiakaki, Chrysoula Perdikogianni, Maria Kalmanti
Department of Pediatric Hematology-Oncology, University of Crete, University Hospital of Herakleion, Greece
Abstract
Primary immune thrombocytopenia (ITP) is one of the most common blood diseases in childhood and is characterized by a low circulating platelet count due to immune-mediated destruction. The natural history of acute ITP in children is adequately studied. Complete remission occurs in at least 2/3 of cases within 6 months of initial diagnosis. In chronic childhood ITP the thrombocytopenia persists for more than 6 months –according to recent data more than 12 months- with generally good course and outcome. One third of these children have spontaneous remission of the disease from a few months to many years after initial diagnosis. Most remissions are observed early during the course of the disease and only a small number of children have severe thrombocytopenia and haemorrhagic symptoms for more than one year from diagnosis. Despite the exceptional outcome independently of any therapeutic approach, the administration and the type of treatment is a topic for debate. There is no consensus for treatment guidelines, fact that leads to a great diversity into the clinical practice. Important issue for the children with acute disease and serious bleeding symptoms constitutes the small but existing risk for intracranial haemorrhage (ICH). The current therapeutic strategy includes corticosteroids, the intravenous immunoglobulin (IVIG) and the intravenous anti-D immunoglobulin as first line treatment as well as the watch and wait option. Splenectomy is considered effective 2nd line treatment, although there is no agreement about the time and the indications of the procedure. In general, it is recommended for children with well documented, symptomatic chronic disease who have failed or are intolerant of 1st line treatment. Third line treatments have been tried in children in whom splenectomy is refused or contraindicated. Rituximab, has been used for a variety of autoimmune diseases with more experience of its use in adult patients with chronic autoimmune thrombocytopenia. The question is if Rituximab is a treatment of choice for children with serious symptomatic disease after splenectomy, or principally whether the drug could be an alternative as 2nd line treatment. According to data for decreased platelet production in a proportion of patients with ITP, an effort became with the use of recombinant erythropoietin (rhTPO). However, the production of anti-TPO antibodies, led to the generation of non-immunogenic thrombopoietic peptides or non peptide molecules (2nd generation thrombopoietic factors) that stimulate the megakaryopoiesis with the same way as the TPO. Although the preliminary results in the adults are encouraging, their role in the management of children with ITP remains to be estimated by well-designed prospective clinical trials. Recently, the International Working Group for autoimmune thrombocytopenia published proposals, in order to face the heterogeneity in terminology, determinations, response criteria and outcome of the disease in children and adults. According to these the term ‘idiopathic’ is replaced by the ‘primary’ and the acronym ‘ITP’ is maintained for the disease ‘Immune ThrombocytoPenia’ term that replaces several ones previously used.