Inflammation and Chlamydia pneumoniae infection correlate with the severity of peripheral arterial disease

Our aim was to investigate the association of inflammation and Chlamydia pneumoniae infection with the presence and severity of peripheral arterial disease.

Twenty-eight patients whose initial claudication distance (ICD) in the traditional constant-load treadmill test was <200 m, underwent femoral endarterectomy as part of their interventional treatment (group A). Group B consisted of 23 patients whose ICD was >200 m and were put on medication and a daily exercise program. The control group consisted of 30 non-vascular patients of the Ophthalmology Department (group C). We measured the levels of C-reactive protein, fibrinogen, vascular cell adhesion molecule-1 and tumor necrosis factor-alpha, and the titers of IgA and IgG antibodies against C. pneumoniae in the serum of all the patients. Finally, the atheromas and vein segments of group A patients, were immunohistochemically (IHC) examined for the presence of C. pneumoniae.

Peripheral arterial disease (PAD) patients, had significantly higher CRP (p=0.026) and anti-Cp IgA levels (p=0.001) when compared to control subjects, after a multiple linear regression analysis. The odds ratio for the prevalence of femoral atherosclerosis was 3.16 for IgA seropositive patients (CI 1.15-8.67). When comparing group A and group B patients, CRP (p=0.003) and IgA (p=0.011), were significantly correlated with severe PAD. Group A patients with positive immunohistochemical examination of the plaque, had higher anti-Cp IgA levels (p=0.023) and TNF-alpha values (p=0.031), compared to the IHC negative patients. C. pneumoniae was detected in 50% of the femoral atheromas, but in only 3.6% of the veins.

This study supports the hypothesis that inflammation (CRP) and chronic C. pneumoniae infection (IgA seropositivity), have an important role in lower limb atherosclerosis and correlate with the severity of the disease.