77 IN PATIENTS WITH HELICOBACTER PYLORI INFECTION-RELATED IMMUNE THROMBOCYTOPENIA, IS SEROLOGY A MORE SENSITIVE MARKER OF THE INFECTION?. (1st January 2006) - Sahni, A.
Abstract : Objective: There have been several studies suggesting the association of Helicobacter pylori (H. pylori) infection with immune thrombocytopenia. ELISA has a sensitivity of 86-94% in diagnosing H. pylori infection. We tested the hypothesis that if the thrombocytopenia is a result of autoimmunity, the patients with H. pylori infection and immune thrombocytopenia would generate a higher immune response to the bacterium and should have a higher incidence of positive result by ELISA. Methods: We identified patients at the Coney Island hospital over a period of 5 years (2000-2004) who presented with dyspepsia and were diagnosed with H. pylori infection. These were patients who underwent either serology (IgG ELISA test) or gastric or duodenal biopsy to diagnose H. pylori infection. Patients who did not undergo the serological test were excluded from the study. The patients with low platelet counts from no explainable causes were identified from the group. Patients with an explainable cause for the thrombocytopenia (sepsis, medications, hypersplenism, hematological malignancies, etc) were excluded from the study. Serology was checked to determine the incidence of positive IgG by ELISA in these patients with autoimmune thrombocytopenia compared with the patients with no thrombocytopenia to determine if there was a demonstrable difference in the immune response to the bacterium between the two groups. Results: 238 patients at the Coney Island hospital were diagnosed with H. pylori infection using serology, endoscopy, or both from January 2000 to January 2004. Eighty-seven patients did not have a serology and were excluded from the study. Of the remaining 151, 22 were found to have thrombocytopenia. Of these, 5 of 22 had other possible explainable causes of thrombocytopenia (3 had sepsis, 1 with a hematological malignancy, 1 drug related). All of the 17 (100%) patients with immune thrombocytopenia were positive for IgG ELISA for H. pylori. Compared to this 110/129 (85%) of the patients with the H. pylori infections without thrombocytopenia were positive by serology. The same serological kit was used for all of the patients. Conclusions: In patients with H. pylori-related immune thrombocytopenia, serology appears to be a more sensitive marker of the presence of infection than in the nonthrombocytopenic patients.