Tehran University of Medical Sciences International Journal of Hematology-Oncology and Stem Cell Research 2008-2207 7 3 2013 09 15 9 14 Mehrdad Payandeh Medical Biology Research Center, Kermanshah University of Medical Sciences, Kermanshah, Iran. Dariyush Raeisi Medical Biology Research Center, Kermanshah University of Medical Sciences, Kermanshah, Iran. Nasrollah Sohrabi Department of Medical Laboratory Sciences, Para medicine Faculty, Kermanshah University of Medical Sciences, Kermanshah, Iran. Mohammad Erfan Zare Medical Biology Research Center, Kermanshah University of Medical Sciences, Kermanshah, Iran. AND Student Research Committee, Kermanshah University of Medical Sciences, Kermanshah, Iran. Atefeh Nasir Kansestani Medical Biology Research Center, Kermanshah University of Medical Sciences, Kermanshah, Iran. AND Student Research Committee, Kermanshah University of Medical Sciences, Kermanshah, Iran. Nazanin Keshavarz Student research committee, Shiraz University of Medical Sciences, Shiraz, Iran. Samira Gholami Student Research Committee, Kermanshah University of Medical Sciences, Kermanshah, Iran. Amir Hossein Hashemian Department of Biostatistics, Faculty of Public Health, Kermanshah University of Medical Sciences, Kermanshah, Iran. 2015 10 14 Introduction: ITP is an autoimmune blood disorder in which platelet destruction is mediated by anti-platelet antibodies. The mechanisms of anti-platelet antibodies development are still a little known. The rate of some bacterial or viral agents in cause of ITP is well known. Recently, some study proposed that H pylori infection may be associated with ITP and H pylori eradication can improves platelet counts in infected ITP patients. Materials and Method: A baseline platelet count <50×103 µL for 4 weeks prior to study entry were required. These patients were tested for H. pylori infection by urea breath. All positive H pylori patients received triple therapy for 7 or 14 days to eradicate H pylori infection. These patients followed for six months. Results: Of 92 patients with ITP, H pylori infection was found in 59.7% (55/92). After excluding patients with confounding factors, 41 patients were remained. After H pylori eradication, CR wasn’t obtained in any patients. Partial response were obtained only in 3 (7.3%) of the 41 patients and no response in 38 (92.6%) patients. There is a significant difference between the platelet counts of PR and NR groups (P<0.001).  Conclusion: the results of this study and our previously study showed H pylori eradication therapy has beneficial effect for patients with mild thrombocytopenia but the chance of obtaining a response by H pylori treatment is lower in patients with severe thrombocytopenia. https://ijhoscr.tums.ac.ir/index.php/ijhoscr/article/view/450 https://ijhoscr.tums.ac.ir/index.php/ijhoscr/article/download/450/347