Humoral immunity of dTap-IPV vaccine (REPEVAX®) administered one month after dT-IPV vaccine (REVAXIS®) in adults with unknown vaccination history.

This study was to assess the humoral immune response induced by a vaccination schedule routinely used in France in 18-50 year old adults with unknown vaccination history. In this monocentric, prospective study, subjects received one dose of REVAXIS® (dT-IPV, diphtheria, tetanus and poliomyelitis (inactivated) vaccine (adsorbed, reduced antigen(s) content)) (Visit 1) followed by one dose of REPEVAX® (dTap-IPV, diphtheria, tetanus, pertussis (acellular, component) and poliomyelitis (inactivated) vaccine (adsorbed, reduced antigen(s) content)) one month later (Visit 2). Antibodies against diphtheria, tetanus, poliomyelitis types 1, 2 and 3, and pertussis toxin (PT) were measured one month after the administration of REPEVAX® (Visit 3). A total of 136 subjects were included in the study, but blood samples were available for only 73 subjects. Their mean age at inclusion was 33.2 ± 7.3 years. 49.3% of the 73 subjects originated from the WHO African Region, 6.8% from the WHO Western Pacific Region and 5.5% from the WHO European Region. One month after REPEVAX® administration, all subjects had seroprotective antibody titers against diphtheria and tetanus (≥0.1 IU/mL), poliomyelitis types 2 and 3 (≥ 8 1/dil); one subject (1.4%) did not have antibodies against poliomyelitis type 1. The rate of anti-PT seropositivity (≥8 EU/mL) was 94.4%. One dose of REPEVAX® administered one month after a dose of REVAXIS® in subjects with unknown vaccination history induced a high humoral response. These results validate a vaccination schedule routinely used for years that rapidly elicits effective immunization against diphtheria, tetanus, poliomyelitis and pertussis.

Autoimmune thrombocytopenic Purpura and Helicobacter pylori infection.

BACKGROUND: The mechanisms triggering the production of platelet autoantibodies in autoimmune thrombocytopenic purpura (AITP) are poorly understood. Recently, marked improvements in platelet counts have been reported in patients with AITP and concurrent Helicobacter pylori infection after eradication of H pylori by a standard antibiotic regimen. We looked for an association between H pylori infection and AITP in adults. METHODS: Fifty-one adults of white French origin, negative for human immunodeficiency virus (mean +/- SD age, 40 +/- 19.8 years), with AITP and a platelet count of less than 50 x 10(3)/microL at onset were included. Thirty-five consecutive nonthrombocytopenic patients (mean +/- SD age, 43 +/- 22 years) of the same origin and with unknown H pylori status served as control subjects. Antibodies against H pylori were detected by means of an agglutination method in both patients and control subjects. Sex ratio, mean age, hemorrhagic manifestations, response to corticosteroid therapy, and final outcome were compared in H pylori-negative and H pylori-positive patients with AITP. To test for a possible molecular mimicry mechanism, we also used an immunoblot assay to look for specific H pylori antibodies in platelet eluates from 3 H pylori-positive patients with AITP. RESULTS: Seroprevalence of H pylori in patients with AITP (15 [29%]) was not significatively different from that in control subjects (10 [29%]). The H pylori-positive and H pylori-negative patients with AITP did not differ in main characteristics at AITP onset, response rate to corticosteroids, and final outcome. None of the 3 patients investigated had H pylori antibodies in platelet eluates. CONCLUSION: Although the role of H pylori in a subgroup of patients with AITP cannot be excluded, we found no evidence of an association between H pylori infection and AITP.