Helicobater Pylori Infection and Clinical Response to Eradication Therapy in Patients with Immune Thrombocytopenic Purpura (ITP).

We performed a prospective study in order to investigate the controversial association between HP infection and immune thrombocytopenic purpura (ITP). We studied the prevalence of HP infection and the efficacy of its eradication in 57 consecutive adult patients admitted to our ward for ITP. Thirty-three patients were females and 24 were males (median age 58 years; mean platelet count 68±42 x109/L). HP infection was demonstrated by the stool antigen test in 28 patients (49.1%). Such prevalence increased with the age. No statistical difference by gender, platelet count, disease duration, presence of specific platelet autoantibodies (MACE) and therapy regimens was observed between HP-positive and negative patients. On the other HP positive patients were significantly older than HP negative ones (62 versus 54 years, p<0,03) and presented more gastroenteric symptoms (32% versus 7%, p<0,05). Thirteen patients with chronic ITP were given HP eradication since their platelet count was above 20x109/L and they do not need for starting or modifying therapy of ITP for at least 6 months. HP eradication was performed by standard triple therapy based on omeprazole plus clarithromycin and amoxicillin for 1 week. The bacteria was eradicated in all cases. Twelve HP negative ITP patients were followed as controls. The mean platelet count was significantly increased in ITP patients after 3 and 6 months from HP eradication. However, considering as end-point, a platelet count increase of more than 50% over the basal value, the platelet response to the HP eradication appears to be better in eradicated patients only after 3 months of follow-up (83% of positive response versus 57%). We also studied in HP-positive patients the presence of antibodies against CagA citotoxic protein by ELISA method. Seventeen of the patients have anti-CagA antibodies (56%) but the positivity did not correlate with platelet response to the eradication. In conclusion the prevalence of HP infection in our patients with ITP was comparable to that observed in the adult population from the same geographic area. Infection is not associated with clinical or laboratory distinctive features with the exception of tan older age and gastroenteric symptoms. The eradication of the HP infection seems to improve mean platelet count in ITP patients but larger prospective studies are required to validate this approach.