A role of autoimmune process and its link with bacterial infections in initiation or aggravation of atherosclerosis symptoms has been suggested. Antigenic mimicry and cross-reactivity of circulating antibodies have been indicated as some major factors in this process. In this study, the prevalence and titers of IgG and IgA antibodies reacting with glycine extract of H. pylori surface antigens were determined immunoenzymatically (ELISA) in the group of patients with unstable ischaemic heart disease and in patients with aggravated dyspepsia. Our results reveal that elevated titers of IgG anti-H. pylori are more typical for cardiac patients and lower prevalence of IgA anti-H. pylori--for those with aggravated dyspepsia. This supports the hypothesis that intensed humoral response in immunoglobulins class G against some bacterial antigens may play a role in the aggravation of symptoms of coronary atherosclerosis.