Platelet count response to H. pylori treatment in patients with immune thrombocytopenic purpura with and without H. pylori infection: a systematic review

Abstract

Eradication of H. pylori improves thrombocytopenia in some patients with immune thrombocytopenic purpura by mechanisms that remain obscure. Platelet count responses may occur independently of H. pylori infection as a result of the immune modulating effects of macrolide antimicrobials or the removal of other commensal bacteria. We performed a systematic review of the literature to determine the effect of H. pylori eradication therapy in patients with immune thrombocytopenic purpura by comparing the platelet response in patients who were, and who were not infected with H. pylori. MEDLINE, EMBASE, Cochrane central registry and abstracts from the American Society of Hematology (from 2003) were searched in duplicate and independently without language or age restrictions. Eleven studies, 8 from Japan, were included enrolling 282 patients with immune thrombocytopenic purpura who received eradication therapy; 205 were H. pylori-positive and 77 were H. pylori-negative. The odds of achieving a platelet count response following eradication therapy were 14.5 higher (95% confidence interval 4.2 to 83.0) in patients with H. pylori infection (51.2% vs. 8.8%). No study reported bleeding or quality of life. Adverse events were reported in 12 patients. H. pylori eradication therapy was of little benefit for H. pylori-negative patients. These findings strengthen the causal association between H. pylori infection and immune thrombocytopenia in some patients. Randomized trials are needed to determine the applicability of H. pylori eradication therapy across diverse geographical regions.Key words: helicobacter, autoimmunity, purpura, platelets. Citation

Study of host immunity in patients with Helicobacter pylori-related idiopathic thrombocytopenia

“…In support of these hypotheses, a 2009 meta-analysis showed an increase in platelet count following treatment in some patients with ITP regardless of the outcome of eradication therapy [4].…”

“…The improvement in platelet count following H. pylori eradication has been explained by 1) clarithromycin included in eradication regimens has anti-inflammatory properties which may improve platelet autoreactivity by blocking the production of proinflammatory cytokines, and 2) antimicrobials used for H. pylori treatment may eradicate other commensal bacteria that stimulate cross reactive platelet antibodies [4]. In support of these hypotheses, a 2009 meta-analysis showed an increase in platelet count following treatment in some patients with ITP regardless of the outcome of eradication therapy [4].…”

“…the presence of cross reaction between antibodies against the cytotoxinassociated gene (CagA) of H. pylori, and platelet antigens causing accelerated platelet clearance [3]. Another proposed mechanism is modulation of host immunity following colonization by H. pylori to favour the emergence of autoreactive B-1 cells and the enhancement of phagocytic capacity of monocytes together with low levels of the inhibitory Fcγ receptor IIB [4].…”

Correlação entre a bactéria Helicobacter pylori e Púrpura Trombocitopênica Imune- revisão sistemática de literatura dos ultimos cinco anos

“…Porém, há várias hipóteses como, por exemplo, a variação dos genes que expressam CagA a anticorpos que tem reação cruzada com as plaquetas, reação cruzada entre plaquetas e a proteína citotoxina -A, adsorção de antígenos Lewis às plaquetas, ativação das plaquetas e clearance através da interação H.pylori e fator de von Willebrand via glicoproteina plaquetária Ib, variação na frequências de alelos HLA-DRB*11,*14 e HLA-DQB1*03 em pacientes com PT. Em suma, a H. pylori pode ativar os receptores Fcγ em macrófagos e monócitos bem como mimetizar a composição molecular de antígenos plaquetários (CINES et al, 2014) Quanto à indicação de retratamento do H. pylori em casos de pacientes com PTI e reinfecção embora não haja um consenso, a tendência é pelo retratamento (ARNOLD et al, 2009;STASI et al, 2009) sugerem que os pacientes reinfectados possam se beneficiar da terapeutica de erradicação novamente. Os autores questionam o custo/beneficio da triagem do H. pylori e concluem que os gastos para a triagem compensam os do tratamento convencional da PTI.…”

Molecular Epidemiology of Helicobacter pylori in Brazilian Patients with Early Gastric Cancer and a Review to Understand the Prognosis of the Disease

“…In addition, in the last years, H. pylori infection has also been associated with some extradigestive diseases, such as iron-deficiency anemia [20], idiopathic thrombocytopenic purpura [21,22], cardiovascular diseases [23,24], hepatobiliary diseases [25,26], and diabetes mellitus [27], among others.…”