Chlamydia pneumoniae seropositivity and risk of developing coronary heart disease in Western Saudi Arabia

OBJECTIVE: To estimate the seroprevalence of IgG and IgA antibodies against Chlamydia pneumoniae (C. pneumoniae) among a sample of the Saudi population, and to evaluate whether there is a relationship between seropositivity to chronic infection with C. pneumoniae and the manifestation of symptomatic coronary heart disease (CHD).

METHODS: We collected 273 sera samples from CHD patients and 273 sera samples from healthy matched controls from the Western region of Saudi Arabia during the period from November 2004 to May 2005. We tested anti-chlamydial IgG and IgA antibodies using enzyme-linked immunosorbent assay technique.

RESULTS: We found 239 (87.5%) patients and 213 (78%) controls positive for C. pneumoniae IgG antibodies. However, 58 (21.2%) patients and 55 (23.9%) controls were positive for C. pneumoniae IgA antibodies. These results indicate a significant correlation between the presence of IgG antibodies and the development of CHD (p=0.003). Data of this study showed that the presence of IgG antibodies has a 2-fold increase risk in development of CHD. We found no significant correlation between the existence of IgA antibodies and CHD.

CONCLUSION: Our study indicates that C. pneumoniae infection plays an important role in the development of CHD in the Saudi community, emphasizing the importance of developing strategies for prevention and control against this type of bacterial infection. However, we need further study throughout the Kingdom to approve these results in all regions.