Background: Chlamydia pneumoniae infection is associated with chronic diseases such as asthma, reactive arthritis, and atherosclerosis. Several investigations and experimental results indicate an excessive immune response to heat shock protein (hsp) 60 as a possible common pathogenetic link between Chlamydia pneumoniae infection and the associated chronic diseases.
Case Report: A 46-year old woman with persistent C. pneumoniae infection and Reiter’s syndrome had been treated for three years with antibiotics and nonsteroidal anti-inflammatory drugs without success.
However, she was repeatedly free of complaints for several months following two-week cycles taking oral dilutions of Chlamydia trachomatis daily.
Conclusions: The placebo effect does not seem sufficient to explain the clinical benefits obtained repeatedly by drinking dilutions of C. trachomatis. Induction of oral tolerance (immune modulation) to
hsp60 may have occurred, leading to the clinical benefits. The known risk factors for atherosclerosis do not account for all cases of atherosclerosis. If autoimmunity to hsp60 is involved in
the pathogenesis of atherosclerosis, so natural acquisition of oral tolerance to hsp60 may contribute to the geographical differences in atherosclerosis prevalence.

Keywords: Administration, Oral, Antigens, Bacterial - administration & dosage, Autoimmunity, Chaperonin 60 - immunology, Chlamydia Infections - complications, Chlamydia Infections - immunology, Chlamydia trachomatis - immunology, Chlamydophila pneumoniae, Chronic Disease, Immune Tolerance, Models, Immunological, Reiter Syndrome - etiology, Reiter Syndrome - immunology, Reiter Syndrome - therapy