Failure to correlate <i>C. pneumoniae</i> with late onset Alzheimer’s disease

Abstract

<i>Chlamydia pneumoniae</i> is a common cause of community acquired respiratory infections such as pharyngitis, bronchitis, and pneumonia. The detection of <i>C. pneumoniae</i> in 17 of 19 brain samples from patients diagnosed with AD using PCR, RT-PCR, culture, electron microscopic and immunohistochemical analysis recently has been reported.¹ We conducted a pilot study to confirm these observations. Brain samples, from AD cases (n = 9, including parahippocampal gyrus, entorhinal cortex, and temporal cortex) and non-AD cases (n = 2, temporal cortex and hippocampus) were examined as a blind panel using PCR and immunohistochemistry. Immunohistochemistry (figure) was performed on impression slides taken from the frozen brain samples using a <i>C. pneumoniae</i>–specific monoclonal antibody (DAKO). Nested PCR procedures were performed using sets of primers specific for <i>C. pneumoniae</i>, namely the 76-kd protein gene1 and the rpoB gene encoding the RNA polymerase beta subunit (see the figure),² as well as broadly reactive pan-<i>Chlamydia</i> primers targeting the 16S ribosomal RNA gene in <i>Chlamydia</i> and <i>Chlamydia</i>-like organisms.³