Purification of Placenta-Eluted Gamma Globulins and Their Strong Effect against Graft-versus-Host Reactions In Vitro and In Vivo

A retrospective study was performed to determine the prevalence of Helicobacter pylori (H pylori) infection, the effect of H pylori eradication on platelet counts, and the characteristic clinical features of chronic immune or idiopathic thrombocytopenic purpura (ITP) with H pylori infection. H pylori infection was found in 300 patients, a group that was significantly older (P < .005) and had more cases of hyperplastic megakaryocytes in the bone marrow (P = .01) than patients without H pylori infection. H pylori eradication therapy was performed in 207 H pylori-positive ITP cases, and the platelet count response was observed in 63% of the successful eradication group and in 33% of the unsuccessful eradication group (P < .005). In the successful group, the complete remission and partial remission rates were 23% and 42%, respectively, 12 months after eradication. In the majority of responders, the platelet count response occurred 1 month after eradication therapy, and the increased platelet count continued without ITP treatment for more than 12 months. H pylori eradication therapy was effective even in refractory cases, which were unresponsive to splenectomy. In conclusion, H pylori infection was involved in most ITP patients older than 40 years in Japan, and eradication therapy should be the first line of treatment in H pylori-positive ITP patients.     

The long-term efficacy of Helicobacter pylori eradication therapy in patients with idiopathic thrombocytopenic purpura

BACKGROUND AND AIM: A beneficial effect of Helicobacter pylori (H. pylori) eradication in patients with H. pylori-positive idiopathic thrombocytopenic purpura (ITP) has been reported by several investigators; however, it was not clear whether the recovered platelet count after H. pylori eradication was maintained for a long period. METHOD: Thirty-eight ITP patients who were examined for H. pylori infection were assessed. H. pylori-positive patients received a standard antibiotic therapy for H. pylori eradication. We investigated the long-term effect of H. pylori eradication on platelet recovery in patients with H. pylori-positive ITP. RESULTS: Of the 38 ITP patients, 26 (68.4%) were positive for H. pylori. The response rate of platelet recovery was 56.5% (13/23 patients). Twelve patients showed complete response (CR) and one showed partial response (PR). The mean platelet counts 6 months after eradication significantly increased from 31 x 10(9)/L to 129 x 10(9)/L in 23 H. pylori-eradicated patients (P < 0.001). The median platelet counts of responders 1, 2, 3, and 4 years after eradication were 168 x 10(9)/L (n = 10), 193 x 10(9)/L (n = 9), 168 x 10(9)/L (n = 7), and 243 x 10(9)/L (n = 4) after a mean follow-up of 25.8 months. CONCLUSION: Eradication therapy for H. pylori-positive patients with ITP was effective and a favorable effect was maintained for long periods.     

Helicobacter pylori eradication in the management of patients with idiopathic thrombocytopenic purpura

PURPOSE: To investigate the relation between Helicobacter pylori infection and the clinical features of idiopathic thrombocytopenic purpura (ITP), and to examine the effects of H. pylori eradication on platelet counts. METHODS: A(13)C urea breath test for H. pylori infection was performed in a cohort of 137 consecutive patients with ITP. Patients who tested positive received standard eradication therapy if their platelet count was <50 x 10(9)/L or if they had symptoms of dyspepsia. RESULTS: H. pylori infection was detected in 64 patients (47%), and was not associated with dyspepsia or other clinical or laboratory features. Eradication therapy was successfully administered to 52 patients. Platelet responses were observed in 17 (33%) of these patients, which lasted for more than 1 year in 11 patients. Duration of ITP was shorter among responders than nonresponders. Only one response was observed among patients with severe thrombocytopenia (platelet count <30 x 10(9)/L). CONCLUSION: The prevalence of H. pylori infection in patients with ITP is similar to that found in the general population. Infection is not associated with distinctive features of the disease. H. pylori eradication may improve the platelet counts in adults in whom the ITP is of recent onset and in those with less severe degrees of thrombocytopenia, but was not effective in patients with chronic severe ITP.     

Effect of Helicobacter pylori eradication in patients with chronic idiopathic thrombocytopenic purpura-a randomized controlled trial

OBJECTIVE: Eradication of Helicobacter pylori was reported to increase the platelet counts in some H. pylori-positive patients with chronic idiopathic thrombocytopenic purpura (cITP). However, the efficacy of the eradication was quite different according to the previous reports. To determine whether H. pylori infection can contribute to cITP, we performed a randomized controlled trial for the first time. In addition, to investigate the possible pathogenic mechanisms and to predict the platelet response after eradication of H. pylori in each cITP patient, several H. pylori virulence factors, the urease activities of the infected H. pylori strains, and the titers of anti-CagA IgG antibodies were analyzed. METHODS: Patients with cITP underwent gastroscopy and gastric H. pylori infection was confirmed by culture. H. pylori-positive cITP patients were randomly assigned to either the eradication or the non-eradication group. The eradication group received a standard antibiotic therapy for H. pylori. Response to treatment was defined as complete (CR) if the platelet count was above 150x10(3)/microl and partial (PR) if the platelet count increased by more than 50x10(3)/microl above the pretreatment count. The virulence factors were investigated by PCR and PCR-based direct sequencing. Anti-CagA IgG antibody titer of each patient's serum was measured by ELISA. RESULTS: Of the 36 ITP patients, 25 (69.4%) were positive for H. pylori and eradication was achieved in 84.6% of these patients. The platelet response was significantly different between the eradication group (46.2%) and the non-eradication group (0%). No significant differences were found in clinical factors between the responders and the nonresponders. H. pylori virulence factors and the urease activity were not associated with the response. The titers of anti-CagA antibodies in the responders were significantly higher than those in the nonresponders (p=0.04). CONCLUSIONS: H. pylori eradication treatment is a favorable therapeutic option for H. pylori-positive patients with cITP. Moreover, an ELISA titer of serum anti-CagA antibody may be a good predictor of platelet recovery, and immunological reaction between platelet and anti-CagA antibodies may have some relation to the pathogenesis of H. pylori-positive patients with cITP.     

Platelet recovery in patients with idiopathic thrombocytopenic purpura after eradication of Helicobacter pylori

The relationship between Helicobacter pylori infection and idiopathic thrombocytopenic purpura (ITP) has been investigated in several studies. We investigated the prevalence of H. pylori infection and the clinical effects of eradication in 22 Japanese patients with chronic ITP. H. pylori infection was found in 14 (63.6%) of the patients by histologic and culture examinations of biopsy samples obtained by gastrointestinal endoscopy. H. pylori was eradicated by proton pump inhibitors and 2 kinds of antibiotics in 13 (92.9%) of the 14 patients in whom the results of treatment could be evaluated. Five (38.4%) of those 13 patients had platelet recovery (platelet count of more than 100 x 10(9)/L and an increase of more than 30 x 10(9)/L with respect to the baseline value) after eradication. The median follow-up period was 15 months. One patient who had a complete response had a partial relapse after cessation of prednisolone treatment without any evidence of H. pylori reinfection. Another patient, in whom H. pylori was not eradicated even after 2 treatment sessions, had a partial response after treatment. A screening examination for H. pylori infection may be necessary for Japanese patients with newly diagnosed ITP. Although the exact mechanism underlying platelet recovery after H. pylori eradication is not clear, the results of this study indicated that H. pylori eradication treatment is a good option for some patients with chronic ITP.     

Does Helicobater pylori initiate or perpetuate immune thrombocytopenic purpura?

To determine the prevalence of Helicobacter pylori (H pylori) infection in North American patients with immune thrombocytopenic purpura (ITP) and the effect of H pylori eradication on the platelet count, a prospective study was performed. Seventy-four patients aged 10 years and older (mean age of 41 years) with chronic ITP and a platelet count below 60 x 10(9)/L were enrolled. H pylori infection was found in 22% of patients by means of a breath test and could not be predicted by gastrointestinal symptoms. H pylori-positive patients (52.5 years of age) were older than H pylori-negative patients (38.5 years of age; P =.0035). Fifteen of the 16 H pylori-positive patients were treated and the bacteria was eradicated in 14 (93%). After 3 months, a significant response (platelet count > 50 x 10(9)/L and doubling the initial count) was observed in only one patient. After a median follow-up of 11.5 months, none of the 14 patients had responded. Ten H pylori-negative patients treated with the same regimen also did not increase their platelet counts. In conclusion, unlike several previous reports, this study does not implicate H pylori in the pathogenesis of ITP since the prevalence of H pylori infection was low and eradication of H pylori did not positively influence the course of the ITP.     

Helicobacter pylori infection and chronic immune thrombocytopenic purpura: long-term results of bacterium eradication and association with bacterium virulence profiles

Eradication of Helicobacter pylori may lead to improvement of chronic immune thrombocytopenic purpura (ITP), although its efficacy over time is uncertain. We report the results of H pylori screening and eradication in 75 consecutive adult patients with ITP. We also used molecular methods to investigate lymphocyte clonality and H pylori genotypes in the gastric biopsies from 10 H pylori-positive patients with ITP and 19 H pylori-positive patients without ITP with chronic gastritis. Active H pylori infection was documented in 38 (51%) patients and successfully eradicated in 34 (89%) patients. After a median follow-up of 60 months, a persistent platelet response in 23 (68%) of patients with eradicated infection was observed; 1 relapse occurred. No differences in mucosal B- or T-cell clonalities were observed between patients with ITP and control participants. Of note, the frequency of the H pylori cagA gene (P = .02) and the frequency of concomitant H pylori cagA, vacAs1, and iceA genes (triple-positive strains; P = .015) resulted statistically higher in patients with ITP than in control participants. All asymptomatic H pylori-positive patients with ITP were suffering from chronic gastritis. Our data suggest a sustained platelet recovery in a proportion of patients with ITP by H pylori eradication alone. Overrepresentation of specific H pylori genotypes in ITP suggests a possible role for bacterium-related factors in the disease pathogenesis.     

<Emphasis Type="Italic">Helicobacter pylori</Emphasis> Infection and Idiopathic Thrombocytopenic Purpura

A treatment strategy for idiopathic thrombocytopenic purpura (ITP) is considered with the aim of cure or management of the bleeding tendency. In 1998, Gasbarrini et al reported a high prevalence of Helicobacter pylori infection in patients with ITP and showed that platelet recovery occurred after eradication therapy in most cases. Since then, many studies were performed to evaluate eradication therapy. This article discusses the incidence of H pylori infection in ITP, characteristic clinical features in H pylori-positive ITP, the effectiveness of eradication on platelet count increase, and the mechanisms of development of ITP by H pylori infection. Overall, there was a positive association between H pylori infection and ITP, and eradication of bacterium was accompanied by a significant increase in platelet counts in more than 50% of H pylori-positive ITP cases. These findings suggest that H pylori infection is involved in the mechanisms of thrombocytopenia in most cases of ITP in middle-aged and older patients. This approach could be beneficial to some ITP patients, but there were some uncertainties raised. To confirm the effectiveness of eradication therapy in H pylori-positive ITP, prospective studies conducted in several countries with a new treatment protocol are required, with a large number of ITP cases and longer follow-up.     

Helicobacter pylori eradication can induce platelet recovery in chronic idiopathic thrombocytopenic purpura

We prospectively investigated the prevalence of Helicobacter pylori (H. pylori) infection in a cohort of 54 adult Serbian patients with chronic idiopathic thrombocytopenic purpura (ITP), and examined the effects of its eradication on their platelet counts. H. pylori infection was diagnosed in 39/54 (72.2%) patients, using the 14C-urea breath test; and was significantly higher than in the healthy Serbian population (55% P < 0.05). H. pylori-positive patients were significantly older than H. pylori-negative patients (P = 0.006), though there were no significant differences regarding gender, disease duration, mean platelet counts, previous therapies and spleen status between H. pylori-positive and H. pylori-negative patients. Successful eradication was confirmed in 23/30 (77%) treated patients. Stable platelet recovery was registered in 6/23 eradicated patients (26.1%) and maintained for 18 months. Complete and partial remissions were achieved in two and four patients, respectively, including one highly refractory patient. A significant mean platelet recovery was seen 6 months after successful H. pylori eradication in the group of 23 patients (P < 0.05). No platelet recovery was registered in either H. pylori-negative (n = 15), untreated H. pylori-positive patients (n = 9) or H. pylori-positive non-eradicated patients (n = 7). Even though the pathogenetic mechanisms of H. pylori-induced thrombocytopenia remain obscure, the results of this small prospective study support the use of H. pylori eradication as an effective non-immunosuppressive treatment for chronic ITP.     

幽门螺杆菌感染与特发性血小板减少性紫癜关系的荟萃分析

目的:评价特发性血小板减少性紫癜(ITP)与幽门螺杆菌(H pylori )感染的相关性.方法:检索PubMed、EMBase和CNKI数据库,获取ITP与H pylori 感染的病例-对照研究, 将入选的病例分成4组:H pylori 阳性并成功清除组; H pylori 阳性但清除不成功组; H pylori 阳性未清除治疗组; H pylori 阴性组. 每组均记录进入实验时各患者的基础血小板计数和随访时的血小板计数, 并在组内行荟萃分析.结果:检索文献中纳入21篇病例-对照研究, 其中国外17篇, 国内4篇. 在随访前后, H pylori阳性并成功清除组P LT计数有统计学意义(WMD 61.70, 95%CI:47.58-75.81); H pylori阳性但清除不成功组PLT计数无统计学意义(WMD 11.41, 95%CI:-0.07-22.88); H pylori阳性未清除治疗组P LT计数无统计学意义(WMD 15.77, 95%CI:-7.99-39.54); H pylori阴性组PLT计数有统计学意义(WMD 24.24,95%CI:8.54-39.93).结论:H pylor i 阳性的ITP患者在成功清除H pylori 后PLT计数上升, 但H pylori 感染并不是ITP发生的唯一因素.     

Clonally Expanded T-Cells in the Peripheral Blood of Patients with Idiopathic Thrombocytopenic Purpura and Helicobacter pylori Infection

Eradication of Helicobacter pylori leads to platelet recovery in some patients with idiopathic thrombocytopenic purpura (ITP). Therefore, the pathogenesis of a subgroup of ITP is probably associated with H pylori infection (H pylori-related ITP). If H pylori-related ITP is a definite subgroup of ITP, specific oligoclonal T-cells might accumulate in the peripheral blood (PB). To address this issue, we performed single-strand conformation polymorphism analysis of complementarity-determining region 3 (CDR3) of the T-cell receptor beta-chain genes of PB T-cells. Fourteen ITP patients with H pylori infection and 12 ageadjusted healthy volunteers were studied. Of the 14 patients, 8 patients (responders) exhibited a platelet response after successful H pylori eradication therapy, but 6 patients (nonresponders) did not. Vbeta5.2, Vbeta15, and Vbeta19 gene usage by clonally expanded T-cells in PB obtained before H pylori eradication therapy was significantly higher in responders than in nonresponders or healthy volunteers (Vbeta5.2, P = .023; Vbeta15, P = .004; Vbeta19, P = .036). Furthermore, an abrogation of clonally expanded T-cells was observed after therapy in some responders. These findings suggest that specific T-cell clones accumulate in H pylori-related ITP and that such clones may be associated with immune-mediated destruction of platelets.     

Effect of Helicobacter pylori eradication on platelet recovery in Japanese patients with chronic idiopathic thrombocytopenic purpura and secondary autoimmune thrombocytopenic purpura

The prevalence of Helicobacter pylori infection and the effect of its eradication on platelet count in 48 Japanese patients with autoimmune thrombocytopenic purpura (AITP), including 40 chronic idiopathic thrombocytopenic purpura (ITP) and eight secondary AITP, were investigated. H. pylori infection was found in 25 ITP patients (62.5%) and in two secondary AITP (25%). H.pylori eradication was obtained in 19 of 19 infected ITP patients (100%), who were not in remission (platelets < 100 x 109/l) at the time of infection assessment. During follow-up (median 14.8 months), 12 of 19 H. pylori-eradicated patients (63.2%) showed a significant increase in platelet count accompanied by a significant decrease of platelet-associated immunoglobulin G (IgG). This response was maintained in all responding patients throughout the follow-up period. However, two infected patients with secondary AITP did not show platelet increase after eradication. The assessment of H. pylori infection and its eradication should be attempted in ITP as this approach could be an effective strategy, at least for some of these patients.     

Current status of treatment for patients with idiopathic thrombocytopenic purpura in the Hokkaido area (evaluation of Helicobacter pylori eradication)

Treatment guidelines for patients with idiopathic thrombocytopenic purpura (ITP) have been changed recently due to the clinical application of Helicobacter pylori (H. pylori) eradication but there has been no detailed multi-center analysis of the hematological effects of H. pylori eradication. The Clinical Hematology Forum consists of 11 large hematological departments and divisions in the Hokkaido area. We sent questionnaires to these 11 hematological departments and divisions in March 2003 to obtain information on current treatment strategies for patients with ITP and hematological results after the eradication of H. pylori. Questionnaires were returned by 9 (81.8%) of the 11 departments. Doctors in all hospitals had experience in diagnosis and treatment of H. pylori infection. Diagnostic examinations for H. pylori infection were performed in 54.3% of the registered cases. H. pylori infection was detected in 68.1% of the examined cases, and eradication treatment was performed in 87.7% of H. pylori-positive patients. H. pylori was eradicated in 52 (83.9%) of the 62 patients in whom the results of treatment could be evaluated. Among the patients whose platelet counts were less than 10.0 x 10(4)/microl, platelet recovery was observed in 48.8% of cases with successful eradication, a percentage similar to previously reported percentages in Japan. There was no prognostic factor to predict good responders before eradication treatment. Since the side effects of eradication treatment, including gastrointestinal symptoms and skin eruptions, were not serious, this method might become a front-line treatment for patients with ITP. Patient selection for eradication as an up-front treatment, analysis of the pathophysiology of platelet recovery after eradication and long-term effects should be investigated to make new treatment guidelines for newly diagnosed patients with ITP.     

Effect of eradication of Helicobacter pylori on platelet recovery in patients with chronic idiopathic thrombocytopenic purpura: a controlled trial

Several recent studies have suggested that an association exists between Helicobacter pylori (HP) eradication and improvement in platelet count in a significant proportion of patients with idiopathic thrombocytopenic purpura (ITP). In this controlled study, we prospectively examined adult patients with chronic ITP for HP infection, and assessed the effect of HP eradication on platelet count. One hundred forty-two consecutive Iranian patients with chronic ITP were assessed. Those who met the criteria and had platelet counts >30 x 10(9)/L within the medication-free screening month were enrolled (n = 129; 66 females; mean age, 29.2 +/- 7.0 years). HP-positive patients received a 2-week course of triple HP eradication therapy (i.e., amoxicillin, clarithromycin, and omeprazole) and were followed for 48 weeks. An ITP response was defined as a platelet count of >100 x 10(9)/L 24 weeks after treatment, together with an increase in the platelet count >30 x 10(9)/L over the baseline value. HP infection was detected in 79 (61%) patients. HP-positive patients were significantly older than HP-negative subjects (P = 0.018). HP eradication was successful in 87% (62/71) of those who completed the eradication therapy. Whereas 48% (30/62) of HP-eradicated patients showed an ITP response, no HP-negative patient had an ITP response. The ITP response persisted for 48 weeks in 93% (28/30) of the responders. The ITP responders had a shorter disease duration than the nonresponders (P = 0.002). The management of mild-to-moderate chronic ITP in Iranian patients, especially those with a recent onset of disease, should include an investigation for and eradication of infection with HP.     

Platelet recovery after eradication of <Emphasis Type="Italic">Helicobacter pylori</Emphasis> in patients with idiopathic thrombocytopenic purpura

The association between Helicobacter pylori ( H. pylori) infection and idiopathic thrombocytopenic purpura (ITP) has been reported by several groups. We investigated the prevalence of H. pylori infection and the effectiveness of its eradication in Japanese patients with ITP. H. pylori infection was found in 21 of 30 patients (70.0%) by (13)C urea breath test and presence of serum antibodies to H. pylori. H. pylori was eradicated in 18 of the 21 infected patients (85.7%) by administration of a proton pump inhibitor and two kinds of antibiotics. In only one patient was medication discontinued due to skin rash on the 4th day of treatment. Platelet recovery was obtained in ten patients (55.6%). In two patients with treatment failure, platelet recovery was obtained after successful re-eradication. In three patients without H. pylori infection, platelet counts did not significantly increase with the same treatment. On the other hand, eradication therapy did not affect platelet counts in patients with gastric ulcer. In conclusion, H. pylori eradication can be used for initial treatment with tolerable adverse effects in some ITP patients.     

Platelet activation in Helicobacter pylori-associated idiopathic thrombocytopenic purpura: eradication reduces platelet activation but seldom improves platelet counts

INTRODUCTION: It has been suggested that Helicobacter pylori eradication often increases platelet counts in patients with chronic idiopathic thrombocytopenic purpura (ITP). In addition, H. pylori has been shown to induce platelet activation (CD62p or P-selectin expression) in previous studies. We assessed the response of platelet count and CD62p expression after eradication therapy in patients with ITP and H. pylori infection. METHODS AND RESULTS: We prospectively studied 15 ITP patients diagnosed with H. pylori infection by serology and breath test. A follow-up breath test was used to document eradication. Two out of 15 patients showed improvement in platelet counts after 6 months, 1 of which may have had drug-induced thrombocytopenia. Overall, certain platelet response rate in our series was 6.7% (1/15). We found that platelet CD62p expression by flow cytometry was elevated in 10/15 (66.7%) H. pylori-infected patients, which is a statistically significant difference when compared with 3/33 (9.1%) control ITP patients seronegative for H. pylori (p = 0.002). In addition, eradication therapy decreased CD62p expression (p = 0.04). However, reduction in platelet activation was not associated with an increase in platelet counts (mean 72.4 x 10(9)/l before and 68.7 after therapy; p = 0.4). CONCLUSION: In our series, platelet activation was common in ITP patients with H. pylori, and eradication therapy decreased platelet activation but seldom increased platelet counts. Increased platelet CD62p expression is a putative link between chronic infections and atherosclerosis, but further study is needed to clarify the implications of our observation.     

Successful platelet recovery after the second eradication of Helicobacter pylori with metronidazole in two patients with chronic idiopathic thrombocytopenic purpura

There are many reports on the efficacy of Helicobacter pylori (H. pylori) eradication therapy in patients with H. pylori-positive chronic idiopathic thrombocytopenic purpura (ITP). We administrated metronidazole (MNZ), amoxicillin (AMPC), and a proton-pump inhibitor (PPI) as the second eradication therapy for two patients who failed in the first eradication therapy consisting of PPI, AMPC, and clarithromycin (CAM). Successful eradication and the rapid recovery of platelet counts within one month were achieved in both patients. Recently, H. pylori eradication is considered as the first-line therapy for H. pylori-positive chronic ITP patients. In Japan, the PPI + AMPC + CAM regimen is recognized as the standard eradication therapy for H. pylori. However, the PPI + AMPC + MNZ regimen is also useful for eradication and should be tried as the re-treatment regimen after failure of the first-line CAM-containing regimen.     

Can Eradication Therapy for Helicobacter pylori Really Improve the Thrombocytopenia in Idiopathic Thrombocytopenic Purpura? Our Experience and a Literature Review

Helicobacter pylori has recently been postulated to play a role in the pathogenesis of autoimmune diseases, including idiopathic thrombocytopenic purpura (ITP). We investigated the prevalence of H pylori infection and the effects of its eradication in 61 patients with ITP. H pylori infection was found in 50 patients (83%), an incidence significantly higher than not only healthy volunteers in Japan (60%) but also subjects in other reported ITP series (approximately 43%-71%). In our study, the mean age of H pylori-positive ITP patients (58.0 years) was significantly higher than that of H pylori-negative ITP patients (40.5 years). Bacterium eradication efforts were performed in 29 infected ITP patients and succeeded in 27 patients (93%). The 29 patients with eradicated H pylori infections showed significant increases in platelet counts compared with patients with uneradicated infections or who were H pylori-negative. During the follow-up period (median, 11.0 months), 16 (55%) of 29 patients achieved a major or a minor response. The patients who achieved a major response had not received previous prednisolone therapy, suggesting a relationship between prednisolone therapy and the response to eradication efforts. The assessment of H pylori infection and its eradication should be attempted in cases of ITP, because this approach may be a good new strategy for treating some ITP patients, especially elderly Japanese patients. Some regional factors have been suggested as causes of H pylori-associated ITP.     

Helicobacter pylori eradication: Novel therapy for immune thrombocytopenic purpura? A review of the literature

Eradication of Helicobacter pylori (H. pylori ) from the gastric mucosa has been associated with improvement of several systemic diseases, including immune thrombocytopenic purpura (ITP). Over the last 5 years, several studies have reported improved platelet counts in H. pylori-positive ITP patients following standard triple H. pylori eradication therapy. Review of published studies in which eradication of H. pylori has been performed in the ITP population indicates an overall response rate of 52% in 193 subjects in whom H. pylori was eradicated. Cohorts from Japan and Italy report higher response rates. There is no established mechanism to explain how this organism, which does not invade the gastric mucosa, could be implicated in the pathogenesis of this immune-based platelet disorder. Several theories including molecular mimicry, platelet aggregation, and immunomodulatory effects of macrolides have been proposed to explain the platelet response to anti-H. pylori therapy. Large randomized-controlled studies enrolling patients from various ethnic backgrounds will be necessary to determine the response rate and mechanism of response and to gain a better understanding of the pathogenesis of ITP.     

Eight-year follow-up of patients with immune thrombocytopenic purpura related toH. pyloriinfection

Thrombocytopenia related to Helicobacter pylori infection is a definitive subset of chronic immune thrombocytopenic purpura (ITP) but its long-term prognosis has not been evaluated extensively. The possibility of recurrence of thrombocytopenia after re-infection of H. pylori is another concern. We evaluated 8-year follow-up data for 11 patients with ITP related to H. pylori infection in a single institution. In 2001, patients with chronic ITP were evaluated for H. pylori infection at the Tokyo Metropolitan Komagome Hospital using 13C urea breath test (UBIT). Nineteen patients turned out to be positive and were treated for H. pylori infection. Platelet count 6 months after treatment revealed complete response (CR) in 10 patients and response in one patient. Eight years later, 17 of these 19 patients were re-evaluated for H. pylori infection and platelet count. Platelet counts of the 11 previous responders remained to indicate CR. Two of 13 patients re-examined by UBIT showed positive results and one of these two patients continued to keep normal platelet count. Nonetheless, the prognosis of patients who responded to eradication was excellent.