Chlamydophila (Chlamydia) pneumoniae in the Alzheimer's brain


  • Present address: Ute Dreses-Werringloer, Litwin-Zucker Research Center for the Study of Alzheimer's Disease and Memory Disorder, North Shore-Long Island Jewish Institute for Medical Research, Manhasset, NY, USA

  • Editor: Patrik Bavoil

Correspondence: Alan P. Hudson, Department of Immunology and Microbiology, Wayne State University School of Medicine, Gordon H. Scott Hall, 540 East Canfield Ave., Detroit, MI 48201, USA. Tel: +313 993 6641; fax: +313 577 1155; e-mail:


We assessed the presence and characteristics of the intracellular pathogen Chlamydophila (Chlamydia) pneumoniae in brain-tissue samples from 25 patients with late-onset Alzheimer's disease (AD) and 27 non-AD control individuals. 20/27 AD patients, but only 3/27 controls, were PCR-positive in multiple assays targetting the Cpn1046 and Cpn0695 genes. Culture of the organism from brain-tissue homogenate from one AD patient, and assessment of various chlamydial transcripts in RNA preparations from several patients, demonstrated that the organisms were viable and metabolically active in those samples. Immunohistochemical analyses showed that astrocytes, microglia, and neurons all served as host cells for C. pneumoniae in the AD brain, and that infected cells were found in close proximity to both neuritic senile plaques and neurofibrillary tangles in the AD brain. These observations confirm and significantly extend our earlier study suggesting that this unusual pathogen may play a role in the neuropathogenesis characteristic of AD.