Author(s): Blasi F, Raccanelli R, Cosentini R, Erba M, Denti F
Recent reports suggest an association between Chlamydia pneumoniae and Helicobacter pylori bacteria and atherosclerosis. We studied 51 patients (mean age, 68.3 years) who underwent abdominal aortic aneurysm surgery.ForeachpatientweperformedamicroimmunofluorescencetestforimmunoglobulinG(IgG),IgA,and IgM antibodies to C. pneumoniae specific antigen (TW-183). Anti- H. pylori antibodies were determined by meansofanEIA-Gtest.Eachaorticaneurysmsurgicalspecimenwassampledintomultiplesectionsof0.3cm 2 each and frozen at 2 20 & C. Two samples of each aneurysm were used for a nested PCR with two sets of C. pneu- moniae and two sets of H. pylori specific primers. Specimens were treated with a solution containing 20 mM Tris-HCl, Tween 20–Nonidet P-40 (0.5% [vol/vol] each), and 100 m g of proteinase K per ml and incubated at 60 & C for 1 h and at 98 & C for 10 min. DNA was extracted twice with phenol-chloroform-isoamylic alcohol and precipitated with sodium acetate-ethanol by standard methods. Forty-one patients were seropositive for C. pneu- moniae with past-infection patterns in 32 patients (16 < IgG < 512; 32 < IgA < 256) and high antibody titers in 9 patients (IgG > 512). In 26 of 51 patients, C. pneumoniae DNA was detected in aortic aneurysm plaque specimens. Of these patients, 23 had a serologic past-infection pattern, 2 had an acute reinfection pattern, and 1 was seronegative. Forty-seven of 51 patients were seropositive for H. pylori . In all cases PCR showed no evidence of H. pylori presence in plaque specimens. This study provides data on a possible C. pneumoniae involvement in the pathogenesis of aortic aneurysm and additional evidence for an association between this agent and atherosclerosis. Conversely, notwithstanding a high H. pylori seroprevalence observed, our results tend to rule out the possibility of a direct involvement of H. pylori in atherosclerosis.