Synergistic effect of persistent Chlamydia pneumoniae infection, autoimmunity, and inflammation on coronary risk.
BACKGROUND
Given the role of chronic infections, autoimmunity, and inflammation in atherosclerosis, we studied the joint effect of chronic Chlamydia pneumoniae infection, persistently elevated human heat-shock protein 60 (hHsp60) antibodies, and C-reactive protein (CRP) on coronary risk.


RESULTS
The participants for this prospective nested case-control study were obtained from the Helsinki Heart Study, during which 241 nonfatal myocardial infarctions or coronary deaths occurred among 4081 dyslipidemic middle-aged men. Serum samples taken at baseline and 3 to 6 months before the coronary events that occurred during the 8.5-year period were analyzed for antibodies to C pneumoniae and hHsp60 and the CRP concentration. Compared with persistently low levels, the risk of coronary events was 2-fold for persistently elevated immunocomplex (IC)-bound and/or serum IgA antibodies to C pneumoniae (OR, 1.96; 95% CI, 1.14 to 3.36) and also for serum IgA antibodies to hHsp60 (OR, 2.11; 95% CI, 1.08 to 4.13). The risks associated with elevated antibodies were much higher when CRP was also elevated. Compared with low or transiently elevated levels, the risk of coronary events, with adjustment for age and smoking, was 4.5-fold for persistently elevated CRP and C pneumoniae IC/IgA antibodies together (OR, 4.47; 95% CI, 1.84 to 10.83) and was similar for CRP and hHsp60 IgA antibodies together (OR, 4.36; 95% CI, 1.53 to 12.39).


CONCLUSIONS
Persistently but not transiently elevated C pneumoniae IC/IgA and hHsp60 IgA antibodies, especially when present together with an elevated CRP level, predicted coronary events.
Huittinen
Tiina
T
National Public Health Institute, Aapistie 1, PO box 310, FIN-90101 Oulu, Finland. tiina.huittinen@ktl.fi
Leinonen
Maija
M
Tenkanen
Leena
L
Virkkunen
Hanna
H
Mänttäri
Matti
M
Palosuo
Timo
T
Manninen
Vesa
V
Saikku
Pekka
P
D001323:Autoantibodies / Q000097:blood; D015551:Autoimmunity; D002097:C-Reactive Protein / Q000032:analysis; D016022:Case-Control Studies; D018834:Chaperonin 60 / Q000276:immunology; D023521:Chlamydophila Infections / Q000453:epidemiology / Q000276:immunology*; D002908:Chronic Disease; D015897:Comorbidity; D003327:Coronary Disease / Q000453:epidemiology / Q000276:immunology* / Q000382:microbiology; D005387:Finland / Q000453:epidemiology; D006801:Humans; D007070:Immunoglobulin A / Q000097:blood; D007249:Inflammation / Q000276:immunology / Q000382:microbiology; D008297:Male; D008875:Middle Aged; D016017:Odds Ratio; D011446:Prospective Studies; D018570:Risk Assessment
D001323:Autoantibodies; D018834:Chaperonin 60; D007070:Immunoglobulin A; D002097:C-Reactive Protein