Analysis The Relationship Between Helicobaeter Pylori Inefction And Idiopathic Thrombocytopenic Purpura In Children

BackgroundThe idiopathic thrombocytopenic purpura(ITP) is the most common bleeding disease in childhood,which can be divided into acute idiopathic thrombocytopenic purpura(aITP) and chronic idiopathic thrombocytopenic purpura(cITP) according to it's course exceeding six months.Until now,the cause and the pathogenesis of ITP are not yet completely clear.The Gram-negative bacterium Helicobacter pylori is widely known as a causative agent of gastritis and peptic ulcers and as a high-risk factor for the development of gastric cancer and mucosa-associated lymphoid tissue lympoma.There are increasing data on the association between H.pylori infection and idiopathic thrombocytopenic purpura and the significant increase in platelet count after bacterial eradication.Genetic host factors have been suggested as cause of H. pylori associated ITP in adult.Veneri et al recently found a difference in HLA classⅡallele patterns between ITP patients with or without H.pylori infection.The ITP patients with H.pylori infection showed a HLA-DRB1~*11,~*14 and HLA-DQB1~*03 frequencies significantly higher and a HLA-DRB1~*O3 frequency significantly lower than in H.pylori-negative patients. Until now,the less researches about the association between H.pylori infection and ITP in childhood are few,and the conclusion are controversied.The pathogenesis of ITP is different between in chilidren and in adult.lt very significance to investigate the prevalance of H.pylori infection and the risk factors in children idiopathic thrombocytopenic purpura,the H.pylori eradication therapeutic effect in children ITP patients.The effect of genetic host factors are also need to studied in children ITP patients.Object1.To investigate the prevalance of H.pylori infection and the risk factors in children ITP.2.To investigate the association between H.pylori infection and ITP and the effect of H.pylori eradication in children ITP.3.To investigate the role of HLA-DRB1~*11,HLA-DRB1~*14 in H.pylor infection in ITP patients and the role in identify different subgroups of ITP patients.Material and methodsBetween April 2008 and December 2008,H.pylori was screened in 150 ITP patients aged 2 months～14 years and 150 contrals(2 months～14 years).All patients came from The First Affiliated Hospital of Zhengzhou University.All contrals came from the healthy chilidren who have been checked in The First Affiliated Hospital of Zhengzhou University.Sex,age,the habit of drink and eat,history of parents' H.pylori infection,et al were recorded.H.pylori infection was assessed by the detection of H. pylori stool antigens(ELISA) and H.pylori antibodies in blood(GICA).If they are both positive,we think the patient was infected,or else not infected.17 H.pylori positive cITP patients were treated by H pylori eradication therapy and glucocorticosteroid while other 17 H.pylori-positive cITP patients only treated by glucocorticosteroid.PCR-SSP were used to screen HLA-DRB1~*11,HLA-DRB1~*14 in ITP patients.Propotions were compared with the chi square test.The influencing factor was analyzed by logistic regression.Repeated measure analysis of variances were used to assess-ment the effect of bacterial eradication.A P value below 0.05 was considered stastically significant in all these tests.Results1.H.pylori was found in 40 of 88 aITP patients(45.5%),34 of 72 cITP(54.8%),and 59 of 150 healthy children(39.3%).The H.pylori infection rate in cITP patients was not higher than in the aITP patients and higher than the healthy contral subjects by pearson chi-square test.There was no difference in the sex radio between the infected and uninfected patient populations.Hingher positive rate was found in patients who are elder,have family history,lower per capita living room, infaust living habit.2.The platelet count are not different from ITP patients were treated by bacterial eradication and glucocorticosteroid and patients only treated by glucocorticosteroid.3.The ITP patients with H.pylori infection showed an HLA-DRB1~*11(21.6%versus 9.1%)and HLA-DRB1~*14(14.9%versus 3.9%) frequencies significantly higher than in H.pylori negative patients.The cITP patients showed an HLA-DRB 1~*11 frequencies significantly higher than in aITP patients while there are no HLA-DRB1~*14 frequencies different in aITP patients and cITP patients.Conclusion1.The epidemiologic featureof H.pylori infection in ITP patients as same as in healthy contral.The H.pylori infection rate are not different among aITP patients,cITP patients and healthy children.2.Our data don't conform H.pylori is the necessary etiological factor of ITP and the success of bacterial eradication treatment induce platelet recovery.3.HLA-DRB1~*1,HLA-DRB1~*14 may be the predisposing factor of H.pylori infection in ITP patients.HLA-DRB1~*14 may be used to typing the subgroup of ITP.