Polysorbate 80 and Histidine, a marriage of disaster by Cynthia A. Janak  The addition of L-histidine in the vaccine Gardasil I believe was a bad idea.....So what is happening here? It is my opinion that low levels of histidine could be part of the overall problem that the girls are experiencing. Now my question to the medical research community is what could have caused this drop in histidine levels to cause all these problems?  I have my theory and that is that the immune response that was produced by the vaccine along with the infusion of histidine produced an unexpected reaction in all the girls that have a family history of allergies.
    What happened is that because of this history it stands to reason that these girls already had a higher than normal level of histidine/histamine to begin with. Now we have just added more histidine into their systems therefore overloading and creating a dangerous situation. The immune system now has to deal with the dangerous levels of histidine along with the virus like particles and aluminum. Now we have a programmed immune response to the histidine and the immune system is going to attack it.  Another thing that L-histidine does is that it can pass through the placental wall to the fetus. This could be the direct cause to the spontaneous miscarriage and birth defects in some of the babies. Here is the MSDS (material safety data sheet) quote. Section 11: Toxicological Information, Special Remarks on Chronic Effects on Humans: Passes through the placental barrier in humans. http://www.sciencelab.com/xMSDS-L_Histidine-9927189 
    ....Now this is where it gets interesting. I am going to tell you about the marriage of Polysobate 80 a surfactant and histidine. This is one marriage that was doomed to failure from the start. Let me show you what I just found out a few days ago.  The one thing that I realized after reading it several times is that if you are depleted in your histamine production you have a good chance of having Encephalomyelitis symptoms which is an autoimmune disease.