Inflammation
Lp(a) combined with Chlamydia antibodies in immune complexes nearly quadruples heart attack risk, a Swedish study of 78 cases and 156 controls (Eur Heart J 2000)
Original title: The proatherogenic properties of lipoprotein(a) may be enhanced through the formation of circulating immune complexes containing Chlamydia pneumoniae-specific IgG antibodies
This nested case-control study within the Vasterbotten Intervention Program and WHO MONICA project examined 78 patients with acute myocardial infarction and 156 matched controls, analysing circulating immune complexes for Chlamydia pneumoniae IgG antibodies and Lp(a). A significantly larger proportion of cases than controls had both Lp(a) at or above 13 mg/L and a C. pneumoniae IgG titre at or above 1/2 in circulating immune complexes (odds ratio 3.8). The findings suggest Lp(a) proatherogenic effects may be enhanced or partly mediated through circulating immune complexes containing C. pneumoniae-specific antibodies, potentially explaining part of the link between chronic C. pneumoniae infection and atherosclerosis.
Original abstract
Aims: To investigate a possible relationship between the atherogenic properties of lipoprotein(a) (Lp(a)) and Chlamydia pneumoniae infections.
Methods And Results: The study population was nested within the Västerbotten Intervention Program or the WHO MONICA project. In this incident case-control study, 78 patients who had suffered acute myocardial infarction and 156 matched controls were included. The contents of circulating immune complexes were analysed for C. pneumoniae IgG antibodies and Lp(a). A significantly larger proportion of cases than controls had >/=13 mg. l(-1)Lp(a) and a C. pneumoniae specific IgG antibody titre >/=1/2 in circulating immune complexes (odds ratio=3.8).
Conclusion: The proatherogenic effects of Lp(a) may be enhanced and/or partly mediated through the formation of circulating immune complexes containing C. pneumoniae -specific IgG antibodies. The connection between chronic C. pneumoniae infections and atherosclerosis may, at least in part, be explained by an interaction with Lp(a) through the formation of circulating immune complexes.
Summary written by lp-a.org from the published abstract; figures as published. Page updated 18 August 2026. Methods.