High risk of schizophrenia and other mental disorders associated with chlamydial infections: hypothesis to combine drug treatment and adoptive immunotherapy.

Many microbial factors have been implicated as pathogenic factors in mental disorders. Occurrence of such microbial factors also in the mentally unaffected population raised skepticism against such findings, although each microbial factor may cause mental problems only in some individuals, depending on the individual's immunogenetic disposition. Skepticism against the role of infection in schizophrenia was also fostered by the low impact of antiinfections treatment on the course of disease progression in schizophrenia. We discovered previously that neurotrophins like neurotrophin3 (NT-3) and brain-derived neurotrophic factor (BDNF), involved in processes of neuroplasticity, are also secreted by immune cells, but only by subpopulations of immune cells. Therefore, infection of the immune cell subpopulation, specialized in secreting BDNF, or of another subpopulation, specialized in secreting NT-3, could distort communication of immune cells with the central nervous system (CNS). Chlamydiaceae could cause disbalancement of immune cell sub-populations and, in some individuals with a vulnerable disposition, symptoms of mental illness. Based on previous observations of persisting IgA titers in some patients with mental illness we hypothesize that the intracellular parasites Chlamydiaceae are main pathogenic factors in schizophrenia. We hypothesize furthermore that antiinfectious treatment has to be accompanied by adoptive immunotherapy because antibiotics alone will not restore the balance of immune subpopulations. Our hypothesis is supported by examination of patients with schizophrenia and other mental disorders. Using nested PCR we found a significant prevalence of the intracellular parasites Chlamydophila psittaci, C. pneumoniae and Chlamydia trachomatis (9/18, 50%), as compared to controls (8/115, 6.97%) (chi(2)=25.86, Fisher's exact p two-tailed=5x10(-5)). Treatment with in vitro-activated immune cells together with antibiotic modalities showed sustained mental improvements in patients that did not depend on treatment with antipsychotic drugs. Future controlled studies including sham treatment of patients have to be carried out to prove our hypotheses.