High prevalence of IgG and IgA antibodies to 19-kDa Helicobacter pylori-associated lipoprotein in chronic urticaria

Background: Chronic urticaria has been described in patients with Helicobacter pylori infection. We studied the titer of IgG and IgA type antibodies against H. pylori in patients with and without urticaria of unknown etiology. We also investigated the prevalence of antibodies against H. pylori-associated lipoprotein 20 (lpp20) in patients with and without chronic urticaria. Methods: The concentration of anti-H. pylori antibodies (IgG and IgA) was determined by the RIDA test. The level of anti-lpp20 antibodies was determined by Western blot using various H. pylori antigens (from 19 to 120 kDa). Results: Patients with chronic urticaria and H. pylori infection (subgroup 1, n = 33) had high IgG and IgA titers whereas all patients with chronic urticaria and without H. pylori infection (subgroup 2, n = 23) were seronegative (P = 0.0128 for IgG and P = 0.003 for IgA). Titers in subgroup 1 did not differ significantly from a control group (n = 33) with severe H. pylori-associated gastritis without urticaria. The prevalence of the anti-lpp20 antibodies was significantly higher in subgroup 1 compared to the control group (93.9 vs 21.2%, P < 0.0001 for IgG, and 46.1 vs 6.3%, P < 0.0029 for IgA). Conclusions: We suggest that IgG and IgA antibodies to H. pylori-associated lpp20 may play role in the pathogenesis of chronic urticaria