An Investigation Of Helicobacter Pylori Infection In Children With Idiopathic Thrombocytopenic Purpura

BackgroundIdiopathic thrombocytopenic purpura, also known as autoimmune thrombocytopenic purpura, is the most common bleeding disorder of children with an estimated incidence of five cases per 100,000 persons per year. Boys and girls are equally affected. It is classified as acute or chronic mainly depending on whether the clinical course within 6 monthes or not. In the majority of children, ITP is an acute,self-limited disorder with complete resolution within 6 months. However, about 10% of children with AITP can develop into the chronic form. At present the exact etiology and pathogenesis remain uncertain, but the main theory considers that it is relevanted to the immune disorder is induced by infection. Recently a high prevalence of Helicobacter pylori infection has been reported in adult patients with CITP. Furthermore, after H. pylori eradication therapy in such patients, their platelet counts have been observed to increase, suggesting that H. pylori may be a causative agent of adult CITP.H. pyloni is a gram-negative, curved, S-shaped, or spiral bacillus with one to five sheathed unipolar flagellae. HP infection is a global problem and studies have reported that more than one third of the population in the world infect this bacteria. People are generally susceptible, but the infection occurs mainly in childhood. Its pathogenicity is mainly related to urease, vacuolating toxin A, cytotoxin-associated protein A and other virulence factors. HP is classified into three types in the clinical depending on whether the bacterium expresses VacA and/or CagA. The typeⅠ, with expressing CagA and VacA protein is the high-virulence strain; The typeⅡ, without CagA and VacA protein expressing is the low virulent strain with weak pathogenity; The third type,whose virulence is between the two,only expresses CagA or VacA protein.Currently, the studies on the relationship between HP and the ITP mainly focused on adult, while soldom in children, and mostly are non-randomized studies of small samples with the conclusions inconsistent. In order to explore the relationship between HP infection and children with idiopathic thrombocytopenic purpura, we designed this experiment in the angle of clinic and the typing of HP.ObjectIn order to analyse the relationship between the HP and children ITP, we investigated and analized the rate of HP infection,the type of the HP strain and its influencing factors between the ITP children and normal children, and compared the clinical features of the children ITP with or without HP infection.Subjects160 children with ITP whose age was between 9 months and 14 years in The First Affiliated Hospital of Zheng Zhou University and Zhengzhou Children's Hospital, during March 2009 and October 2009 were enrolled. All of them were diagnosed in line with the 1999 revised diagnostic criteria for ITP by The Pediatric Branch of Chinese Medical Association. Of them, there were 96 AITP and 64 CITP.100 healthy children were enrolled as control group from the outpatient of The First Affiliated Hospital of Zheng Zhou University during the same time. Methods1. Design the questionnaires including the living environment, family economic situation and personal life experiences and habits et al, and carry on the investigation to the ITP children and the control group children.2. Diagnose the HP infection in the children with ITP and the control group healthy children by jointly using two methods.3. Detect CagA and VacA of the children with HP infection using serological method4. The experimental data are analyzed with packages SPSS13.0, P value below 0.05 was considered statistically significant.Results1. The overall positive rate of HP in 160 children with ITP is 39.3% and that of AITP is 37.5%, while CITP is 42.2%. The positive rate of HP in 100 healthy children is 36%.There is no difference among AITP,CITP and the control group(χ2=0.655, P=0.721>0.05).2. The overall positive rate of CagA and VacA in 63 ITP patients with HP infection is respectively 72.2% and 66.7%, and that of 36 AITP is respectively 72.2% and 66.7%. The positive rate of CagA and VacA in 27 CITP is respectively 70.4% and 77.8%. Compared with the control group ,the differences for both CagA and VacA have no statistical significances(χ2=0.946, P=0.623>0.05).3.35 cases infect withⅠ-type strain, accounting for 55.6%;8 cases infect withⅡ-type strain, accounting for 12.7%; 20 cases infect with the third type, accounting for 31.7% in the 63 children with ITP. There are no difference among the AITP, CITP and the control group for HP strains.4. We observed that, in the children with ITP, the most common manifestation is bleeding in the skin, followed by nasal bleeding.There is no significant difference between the HP-positive and negative children. The average count of blood plate for ITP children is (33.15±19.92)×109/L.There are no differences in the counts of blood plate between the ITP patients with or without HP infection. We analyze the bone marrow results of all patients on admission and find the mature megakaryocytes significantly reduced and the naive increase. There are no differences in the bone marrow test resultes between the ITP patients with or without HP infection.5. We analyze the sex,age,the living environment, family economic situation, Personal life experiences and habits of the ITP patients and find that the percentage of HP infection increases with age. The infection of HP in ITP children is associated with the living environment, personal life experiences and habits.ConclusionThere is no difference in the rate of HP infection between ITP group and the healthy control group. The overall infection rate is close to that of the local healthy children. Compared with the healthy control group, the differences for both CagA and VacA have no statistical significance in children ITP with HP-positive. The children ITP group and the healthy control group have the similar HP-strain type, most of which are typeⅠ. In the clinical manifestations there are no significant differences between the HP-positive and negative children and the most common manifestation is bleeding in the skin and mucous membrane, followed by epistaxis, gingival bleeding and so on. There is no difference in the bone marrow test result between the children ITP with or without HP infection. Both of them show that the mature megakaryocytes significantly reduced and the naive increased. The influencing factors for the infection of HP are similar between the children ITP and the healthy children.On the whole, there is no difference between the children ITP with or without HP infection in the comparisons of the rate of HP infection, the type of strain, the clinical manifestations, laboratory examinations and epidemiological perspective. So we conclude that the HP infection isn't the cause of the children ITP.