Researchers from the Medical University of Lubeck in Germany say that they have failed to replicate the tantalizing evidence from a study published two years ago that found Chlamydia in almost all the Alzheimer's brains examined. The German authors used PCR and immunocytochemistry in an attempt to detect either chlamydia DNA or antigens in tissue samples from 20 deceased AD patients. They found no evidence of the bacterium, thereby replicating similar negative results published by a group from the University of Washington last year.
Brian Balin of the Philadelphia College of Osteopathic Medicine, lead author of the report that had found chlamydia in 17 of 19 Alzheimer's brains (and only one of 19 controls), sticks by his original findings. "Unfortunately, the two studies that have been performed have assumed that techniques found successful for other tissue samples could be applied to brain samples that were formalin-fixed and paraffin-embedded," says Balin, whose study used frozen tissue. Because of this and a number of other methodological concerns (see below), Balin believes comparing these studies to his is like comparing apples to oranges.
"Our findings hold such great implications as to how inflammation in the AD brain may be triggered by infection with C pneumoniae that we must demand that studies to replicate and/or validate our first report should be performed with the rigor and comparable techniques that will provide data that can truly be compared and analyzed," says Balin.—Hakon Heimer
No Available References
No Available Further Reading
- Balin BJ, Gérard HC, Arking EJ, Appelt DM, Branigan PJ, Abrams JT, Whittum-Hudson JA, Hudson AP. Identification and localization of Chlamydia pneumoniae in the Alzheimer's brain. Med Microbiol Immunol. 1998 Jun;187(1):23-42. PubMed.
- Gieffers J, Reusche E, Solbach W, Maass M. Failure to detect Chlamydia pneumoniae in brain sections of Alzheimer's disease patients. J Clin Microbiol. 2000 Feb;38(2):881-2. PubMed.
- Nochlin D, Shaw CM, Campbell LA, Kuo CC. Failure to detect Chlamydia pneumoniae in brain tissues of Alzheimer's disease. Neurology. 1999 Nov 10;53(8):1888. PubMed.