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

To test the role of T helper cell Th1 immunity we recruited 24 patients with idiopathic thrombocytopenia associated with H. pylori seropositivity. They were divided into 2 groups: 12 with immune-mediated thrombocytopenia (Group 1) and 12 with non-immune mediated thrombocytopenia (Group 2). We also recruited 10 individuals seronegative for H. pylori (Group 3) as controls. Initial platelet count was significantly lower in Group 1 than Group 2. H. pylori was eradicated in 10 of 12 patients in Group 1 and in all patients in Group 2. Transient improvement (< 3 months) in the platelet count occurred in only 2 patients in Group 1 while improvement for > 6 months was observed in all patients in Group 2. There was a statistically significant direct correlation between platelet count and levels of TNF- and IFN-gamma in both study groups, while a non-significant correlation was seen in Group 3. Thus, H. pylori infection should be considered in the differential diagnosis of all cases of thrombocytopenia, and should be eradicated in all H. pylori-positive patients with thrombocytopenia.