Low levels of IgM antibodies against phosphorylcholine predict development of acute myocardial infarction in a population-based cohort from northern Sweden.
OBJECTIVE
Phosphorylcholine (PC) is one important epitope on oxidized low-density lipoprotein that may play an important role by contributing to the atherogenicity of oxidized low-density lipoprotein. IgM antibodies against PC (anti-PC) are present ubiquitously in the population as natural antibodies. We here determine the association between anti-PC and incidence of myocardial infarction (MI).


METHODS
We studied 462 incident cases of first events of MI and 888 age-matched and sex-matched controls identified through 13 years of follow-up (1987-1999) of participants in a population-based study from northern Sweden. Relative risks (RRs) with 95% confidence intervals (CIs) of incident MI with adjustments for age, sex, geographical region, hypertension, diabetes, BMI, smoking habits, s-cholesterol and high-sensitivity C-reactive protein were determined. Anti-PC levels were measured by enzyme-linked immunoassay.


RESULTS
Low anti-PC values were associated with increased risk of MI. Significant associations were found for values below 26.8 U/ml, corresponding to the lowest 25th percentile, and the highest association was seen below 16.9 U/ml. These results remained almost the same after adjustment for confounding factors (RR crude: 1.56, CI: 1.07-2.28 and RR adjusted: 1.69, CI: 1.09-2.54).


CONCLUSIONS
Low levels of natural IgM anti-PC could play an important role as risk markers for development of MI. Adjustment for common confounders only marginally affected the RR, suggesting that the addition of IgM anti-PC add independent information to the more traditional risk factors.
Clinical Immunology and Allergy Unit, Karolinska Institutet and University Hospital, Stockholm, Sweden.
Hans
H
Grönlund
Göran
G
Hallmans
Jan Håkan
JH
Jansson
Kurt
K
Boman
Max
M
Wikström
Ulf
U
de Faire
Johan
J
Frostegård
D000328:Adult; D000368:Aged; D000906:Antibodies / Q000097:blood*; D016022:Case-Control Studies; D015331:Cohort Studies; D015536:Down-Regulation; D000939:Epitopes; D005260:Female; D006801:Humans; D007075:Immunoglobulin M / Q000097:blood*; D015994:Incidence; D008077:Lipoproteins, LDL / Q000276:immunology*; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000453:epidemiology / Q000276:immunology*; D010767:Phosphorylcholine / Q000276:immunology*; D011159:Population Surveillance; D018570:Risk Assessment; D012307:Risk Factors; D013548:Sweden
D000906:Antibodies; D000939:Epitopes; D007075:Immunoglobulin M; D008077:Lipoproteins, LDL; C099252:oxidized low density lipoprotein; D010767:Phosphorylcholine