Definition, diagnosis and treatment of immune thrombocytopenic purpura.

Regulation of thrombopoiesis: effects of the degree of thrombocytopenia on megakaryocyte ploidy and platelet volume. Blood 1987;70:177-85. 29. Stenberg PE, Levin J. Ultrastructural analysis of acute immune thrombocytopenia in mice: dissociation between alterations in megakaryocytes and platelets. Cazenave J-P, et al. Intrinsic impaired proplatelet formation and microtubule coil assembly of megakaryocytes in a mouse model of Bernard-Soulier syndrome. S, et al. Genetic deletion of mouse platelet glycoprotein Ibbeta produces a Bernard-Soulier phenotype with increased alpha-granule size. Absence of GPIbalpha is responsible for aberrant membrane development during megakaryocyte maturation: ultrastruc-tural study using a transgenic model. I n this issue, Arnold and colleagues document by a systematic review of controlled studies that eradication of H. pylori infection increases the platelet count in patients with immune thrombocytopenic purpura (ITP). 1 This observation, together with data from a previous systematic review, 2 requires that we address two questions. 1) What is the role of H. pylori infection in the pathogen-esis of ITP? 2) What is the role of eradication of H. pylori infection in the management of ITP? These questions require a discussion of the definition, diagnosis, and current treatment of ITP. This discussion focuses on adults, as H. pylori infection is rare in children and two current systematic reviews have only identified studies of ITP in adults. Definition and diagnosis of immune thrombocytopenic purpura ITP is defined as isolated thrombocytopenia with no clinically apparent associated conditions or other causes of thrombocytopenia. 3 This definition provides the basis for the initial patient evaluation. No specific criteria establish the diagnosis of ITP; the diagnosis relies on the exclusion of alternative disorders, such as the examples listed in Table 1. Exclusion of recognized alternative eti-ologies of thrombocytopenia was the basis for the original name for ITP, idiopathic thrombocytopenic purpura. 3 A current perspective has proposed the name primary immune thrombocytopenia for ITP, to distinguish ITP from identifiable alternative secondary etiologies. 4 Should H. pylori infection be considered an alternative disorder, the same as HIV and hepatitis C infec-tions? Does the diagnosis of H. pylori infection exclude the diagnosis of ITP? The current status of H. pylori infection, as indicated in Table 1, is uncertain. H. pylori infection may be an alternative, additional, or incidental unrelated disorder; all three possibilities are suggested by different studies. It is the inconsistency among current studies which has prevented broad acceptance of the association of H. pylori infection with ITP. There …