Vorobjova, Tamara, Ren, Zhigang, Dunkley, Margaret, Clancy, Robert, Maaroos, Heidi-Ingrid, Labotkin, Rait, Kull, Karl, Uibo, Raivo. Blackwell; 2006. Response of IgG1 and IgG2 subclasses to Helicobacter pylori in subjects with chronic inflammation of the gastric mucosa, atrophy and gastric cancer in a country with high Helicobacter pylori infection prevalence.