S100A8 and autoimmune thrombocytopenic purpura: Although the pathogenesis of H. pylori-associated ITP is still uncertain, several studies have suggested that H. pylori virulence factor, cytotoxin-associated gene A (CagA), stimulates the development of anti-CagA antibodies (Abs) that cross-react with platelet surface antigens (Ags), resulting in thrombocytopenia [7–9].