IgM antibody level against proinflammatory bacterial peptidoglycan is inversely correlated with extent of atherosclerotic disease.
OBJECTIVE
Atherosclerosis may lead to acute clinical events by rupture of a vulnerable atherosclerotic plaque. Previously, we demonstrated that peptidoglycan (PGN), a major cell wall component of gram-positive bacteria that induces production of proinflammatory cytokines through TLR2 and CD14, is prevalent in atherosclerotic lesions with histological features associated with plaque vulnerability. We hypothesized that in atherosclerotic patients antibody levels against PGN may differ compared with matched controls.


RESULTS
ELISA was performed to measure immunoglobulin levels against PGN in sera of 80 atherosclerotic patients versus 77 control patients with an increased cardiovascular risk, frequency-matched for age, sex and risk factors for atherosclerotic disease. In all patients and controls, intima-media (IMT) thickness was assessed using an array transducer. Significantly lower levels of IgM directed against PGN were found in atherosclerotic patients compared with the control patients without clinically manifested disease (P = 0.02). The IgM levels against PGN decreased with increasing mean common carotid IMT thickness (P = 0.006).


CONCLUSIONS
These results show that patients suffering from atherosclerotic disease have decreased IgM levels against PGN. The data suggest that an antibody response against PGN could have a protective effect against the development or activity of atherosclerotic disease.
Nijhuis
Manon M Oude
MM
Experimental Cardiology Laboratory, Heart Lung Center Utrecht, University Medical Center, The Netherlands.
van der Graaf
Yolanda
Y
Melief
Marie-José
MJ
Schoneveld
Arjan H
AH
de Kleijn
Dominique P V
DP
Laman
Jon D
JD
Pasterkamp
Gerard
G
D000328:Adult; D000368:Aged; D000888:Antibodies, Anti-Idiotypic / Q000032:analysis / Q000276:immunology*; D001161:Arteriosclerosis / Q000276:immunology* / Q000382:microbiology / Q000503:physiopathology*; D015415:Biomarkers / Q000032:analysis; D016022:Case-Control Studies; D003430:Cross-Sectional Studies; D004730:Endothelium, Vascular / Q000378:metabolism / Q000473:pathology; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006094:Gram-Positive Bacteria; D006801:Humans; D007075:Immunoglobulin M / Q000032:analysis*; D007421:Intestine, Small / Q000382:microbiology; D008297:Male; D008875:Middle Aged; D010457:Peptidoglycan / Q000276:immunology / Q000378:metabolism*; D011379:Prognosis; D018570:Risk Assessment; D012680:Sensitivity and Specificity; D012720:Severity of Illness Index
D000888:Antibodies, Anti-Idiotypic; D015415:Biomarkers; D007075:Immunoglobulin M; D010457:Peptidoglycan