Abstract-Heat shock protein 60 (Hsp60) and Chlamydia pneumoniae infection have both been associated with cardiovascular diseases. Our aim was to study the role of Hsp60 antibodies as coronary risk predictors and their association with C pneumoniae infection and inflammation. This was a prospective, nested, case-control study. The cases consisted of 239 middle-aged Finnish men who developed myocardial infarction or coronary death during the follow-up. Baseline levels of IgA and IgG antibodies to human-specific and C pneumoniae-specific Hsp60 were measured by enzyme immunoassay. Human Hsp60 IgA, but not IgG or C pneumoniae Hsp60, antibodies were a significant risk factor for coronary events (odds ratio 2.0, 95% CI 1.1 to 3.6, when the fourth and first quartiles are compared). When an elevated human Hsp60 IgA antibody level (above the second quartile) was present simultaneously with a high C pneumoniae IgA antibody level (the third quartile) and an elevated C-reactive protein level (the second quartile), compared with all factors at low levels, the risk was 7.0 (95% CI 2.6 to 19.1) without adjustment and 5.0 (95% CI 1.8 to 14.2) when adjustment was made for age and smoking. In conclusion, an elevated human Hsp60 IgA antibody level was a risk factor for coronary events, especially when it was present together with C pneumoniae infection and inflammation.

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. Methods and 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.

Host immune response to Chlamydia pneumoniae heat shock protein 60 is associated with asthma. T. Huittinen, D. Hahn, T. Anttila, E. Wahlström, P. Saikku, M. Leinonen. #ERS Journals Ltd 2001. ABSTRACT: Chlamydia pneumoniae infection has been associated with asthma. It has also been suggested that heat shock protein 60 (Hsp60) belonging to a class of highly conserved proteins may play a role in the pathogenesis of chlamydial infections. The purpose was to study whether the host immune response to C. pneumoniae Hsp60 is associated with asthma and decreased pulmonary function.An enzyme immunoassay was used to measure immunoglobulin-(Ig)A and IgG antibodies against recombinant C. pneumoniae Hsp60 and human Hsp60 in a study group consisting of 24 cases of recently symptomatic asthma and 62 nonasthmatic controls.A strong (r~0.50) and significant (pv0.001) correlation was observed between C. pneumoniae and human Hsp60 IgA antibodies, but only C. pneumoniae Hsp60 IgA antibodies were significantly associated with asthma (p~0.02). Pulmonary function, as measured by forced expiratory volume in one second, also inversely correlated (r~-0.23, p~0.04) with the quantity of C. pneumoniae Hsp60 IgA antibodies, suggesting an association with the severity of pulmonary obstruction.By showing an association of Chlamydia pneumoniae heat shock protein 60 immunoglobulin A antibodies with asthma, the results support the hypothesis of an association between Chlamydia pneumoniae infection and asthma and support the need for further investigations on the role of heat shock protein 60 in the pathogenesis of asthma.

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