Background Immune thrombocytopenic purpura (ITP) is an autoimmune disease characterized by platelet destruction resulting from autoantibodies against platelet proteins, particularly platelet glycoprotein IIb/IIIa. patients with ITP than in controls (1567.8 753.2 via 1763.2 641.8 integrated optical density (IOD) units). There was a small increase of Hsp71 after recovery from ITP. The titers of plasma antibodies against Hsp60 and Hsp71 were also examined. Antibodies against Hsp71 were more common in ITP patients (15/29) than in control children (5/30). The titer of anti-Hsp71 was also higher in children patients with ITP. The prevalence of ITP children with antibodies against Hsp71 (51.7%) was as high as those with antibodies against platelet membrane glycoproteins (58.3%). Conclusions In summary, pediatric patients with ITP showed no detectable expression of Hsp60 in lymphocytes and a high prevalence of antibody against Hsp71 in plasma. These changes add to our understanding of the pathogenesis of ITP and may be important for the diagnosis, prognosis and treatment of ITP. Background Immune thrombocytopenic purpura (ITP) is an autoimmune disease characterized by a low platelet count secondary to accelerated platelet destruction by antiplatelet antibodies that generally recognize platelet membrane glycoproteins (GPs) [1]. The triggering or immunogenic stimulus involved and the role of antiplatelet antibodies in the disease remain unclear. There is an unbalanced immune TNFRSF4 response due to inflammation (i.e., viral infection, autoimmunity), or to exposure to environmental agents (i.e., drug, H2O2) [2-6]. Whether the stimulus is endogenous, i.e. truly “self” or exogenous (“non-self”) is unknown. Some recent evidence argues for an immune-mediated mechanism in ITP-increased HLA-DR expression, defects in cellular and humoral immunity, and specific autoantibody production. There are several forms of management of ITP ranging from drugs such as corticosteroids, a variety of immunosuppressants and immunoglobulins to splenectomy [2,6,7]. However some patients may be receiving unnecessary treatment especially in the case of pediatric patients [8] as the cause and etiopathogenesis of ITP remain unknown. Heat shock proteins (Hsp) are highly conserved proteins found in prokaryotes and eukaryotes. Induction of Hsps can be triggered by many stresses. These include exposure to supraoptimal temperatures (heat shock) and to various chemicals (xenobiotics, drugs, growth factors, hormones). Pathological states incurring during viral, bacterial or parasitic infections, fever, inflammation, malignancy or autoimmunity, can also induce an increase in synthesis of Hsps [9-12]. Many Hsps are also expressed at low levels under normal physiological conditions. Hsps are usually grouped into several families (Hsp110, Hsp90, Hsp/Hsc70 (Hsc: Heat shock cognate), Hsp60, Hsp47 and the small Hsps (Hsp10-30) on the basis of their apparent molecular masses after sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE). Hsps can act as intracellular chaperones of naive, aberrantly folded or mutated proteins, as stimulators of cytokine signal transduction cascades, as well as in cytoprotection against the purchase KU-57788 stress stimuli described above [11,13-15]. A role of Hsps in the inflammatory response is suggested by different findings. Hsps participate in cytokine signal transduction and in the control of cytokine gene expression [16]. Hsps enhance antigen presentation to T lymphocytes, can be displayed on the surface of cells and may be important in targeting cytotoxic cells [16,17]. Moreover, recent investigations also indicate that Hsps have the ability to modulate the cellular immune response since as cellular chaperones, they participate in transport through the various cellular compartments. Thus Hsps may act in transfer of peptides between cellular compartments, and in binding endogenous antigenic peptides and transporting them to the major histocompatibility complexes [18-20]. Hsps have also been reported to be involved in tumorogenesis and in inflammation [21-23]. Many investigations have shown that Hsps and autoantibodies to these proteins play a role in the pathogenesis and/or prognosis of certain diseases [24-31]. Since an important component of ITP is mediated by autoantibodies, we decided to examine if antibodies against Hsps could be detected in pediatric patients with ITP. We also checked if ITP was accompanied by fluctuations in the levels of Hsp60, of the inducible member of the Hsp70 family referred to here as Hsp71 and if the expression of these Hsps changed after recovery from ITP. The data show that Hsp60 is not detectable in lymphocytes of most pediatric ITP patients. Whether the expression of Hsp60 was much lower or totally absent in the ITP children is unknown at the moment. Finally these patients show a high prevalence of antibody against Hsp71 that may purchase KU-57788 be of clinical significance. Methods Subjects and groups The present study comprised two different groups. The first ITP group consisted of 29 ITP pediatric patients aged from 7 to 10 years (male: 18, female: 11) and was conducted from purchase KU-57788 March to November of 2000 in Wuhan. The second group consisted of 6 different ITP pediatric patients.