Thimerosal Alters Immune Function

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Mercury Containing Preservative Alters Immune Function

By Neil Osterweil, Senior Associate Editor, MedPage Today
Reviewed by Zalman S. Agus, MD; Emeritus Professor at the University of Pennsylvania School of Medicine.

DAVIS, Calif., March 21 - Thimerosal, a mercury-containing organic no longer used as a preservative in many pediatric vaccines, can disrupt certain antigen presenting cells and may affect the immune response to external factors, reported investigators here.

...They found that at concentrations of 20 parts per billion, exposure of the dendritic cells to thimerosal altered the normal cross-talk between the calcium channels RyR12 and IP3R1, thereby "garbling the normal signaling system between them."

In addition, exposure to the compound resulted in irregular secretion by the dendritic cells of the pro-inflammatory cytokine interleukin-6...

The finding suggests that in addition to its known neurotoxic properties, ethylmercury may also be an immunotoxicant, the authors said.

"A practical implication of the present findings has relevance to the commercial uses of thimerosal as an antimicrobial agent in vaccines and consumer products since they identify dendritic cells as sensitive targets for thimerosal and ethylmercury-mediated dysfunction," they wrote. "Given the importance of dendritic cells as a front line in regulating lymphocyte mediated immunity and tolerance, altering dendritic cell functions by forms of ethylmercury should be considered when assessing contributions to altered immune function."

http://www.medpagetoday.com/InfectiousDisease/Vaccines/tb/2900

In other studies:

Mutter J, Naumann J, Schneider R, Walach H, Haley B
Mercury and autism: accelerating evidence?
Neuro Endocrinol Lett. 2005 Oct;26(5):439-46.

...Recently, it was found that autistic children had a higher mercury exposure during pregnancy due to maternal dental amalgam and thimerosal-containing immunoglobulin shots. It was hypothesized that children with autism have a decreased detoxification capacity due to genetic polymorphism. In vitro, mercury and thimerosal in levels found several days after vaccination inhibit methionine synthetase (MS) by 50%. Normal function of MS is crucial in biochemical steps necessary for brain development, attention and production of glutathione, an important antioxidative and detoxifying agent.

Repetitive doses of thimerosal leads to neurobehavioral deteriorations in autoimmune susceptible mice, increased oxidative stress and decreased intracellular levels of glutathione in vitro. Subsequently, autistic children have significantly decreased level of reduced glutathione. Promising treatments of autism involve detoxification of mercury, and supplementation of deficient metabolites.

http://www.neurotransmitter.net/autismgenetic.html

Cohly HH, Panja A
Immunological findings in autism.
Int Rev Neurobiol. 2005;71317-41.

The immunopathogenesis of autism is presented schematically in Fig. 1. Two main immune dysfunctions in autism are immune regulation involving pro-inflammatory cytokines and autoimmunity. Mercury and an infectious agent like the measles virus are currently two main candidate environmental triggers for immune dysfunction in autism. Genetically immune dysfunction in autism involves the MHC region, as this is an immunologic gene cluster whose gene products are Class I, II, and III molecules. Class I and II molecules are associated with antigen presentation. The antigen in virus infection initiated by the virus particle itself while the cytokine production and inflammatory mediators are due to the response to the putative antigen in question. The cell-mediated immunity is impaired as evidenced by low numbers of CD4 cells and a concomitant T-cell polarity with an imbalance of Th1/Th2 subsets toward Th2. Impaired humoral immunity on the other hand is evidenced by decreased IgA causing poor gut protection. Studies showing elevated brain specific antibodies in autism support an autoimmune mechanism...

http://www.neurotransmitter.net/autismgenetic.html