RESUMEN
<p><b>OBJECTIVE</b>To investigate the role of Helicobacter pylori (Hp) and its products cytotoxin-associated protein (Cag A), vacuolating cytotoxin (VacA) in childhood acute idiopathic thrombocytopenic purpura (aITP), to evaluate the effect of Hp on their clinical outcome.</p><p><b>METHODS</b>Subjects were enrolled according to case-control design, including 184 aITP children and 154 healthy controls. They were inquired for demographic characteristics, the risk factors regarding Hp infection and ITP through a uniformed questionnaire. Patients with Hp infection were diagnosed by combined detection of serum Hp antibodies and stool antigens. CagA and VacA proteins were tested by ELISA method. In addition, clinical data and follow-up data of aITP children were collected. Non-conditional logistic regression and t test were applied for statistical analysis.</p><p><b>RESULTS</b>(1) The prevalence of Hp infection in aITP children and controls were 41.30% and 35.71%, respectively. No association between Hp infection and children aITP was found with OR of 1.170 (95%CI: 0.7163 - 1.673) after adjusting for confounding variables. (2) No statistical differences regarding initial platelet counts, megakaryocytes counts and the constituent ratio were found between the aITP children with and without Hp infection (P > 0.05). (3) No differences regarding initial platelet counts were found between aITP children with and without the expression of CagA (P > 0.05). The follow-up data showed that 32.88% of aITP children with Hp infection, as well as 29.70% of aITP children without Hp infection developed into cITP. No association between Hp infection and development to cITP was found with adjusted OR 1.171 (95%CI: 0.555 - 2.11 2).</p><p><b>CONCLUSIONS</b>The results didn't suggest that Hp is unlikely to play a role in the onset of childhood aITP, and in the development of aITP to cITP.</p>