Vaccines, Immune Function and Disease
By Jacob Schor, ND
Many believers in alternative medicine, especially many of our patients, devoutly avoid vaccinations. The point of this article is not to argue the pros and cons of vaccinations but to review some fascinating data on immune function and disease.
Before scientists knew that endotoxins in cow manure dust stimulated the immune system and lowered risk of lung cancer, they already knew of another dust that was protective. Back in the 1970s, data showed that people working in cotton factories had a lower risk of lung cancer. Cotton dust, like cow manure, contains endotoxins.
Harvey Checkoway at the University of Washington has published a series of papers about this. He and his colleagues have followed the cancer rates of female cotton textile workers in Shanghai, China, for years. The more dust these women breathed, the lower their incidence of cancers. Note that I wrote the plural – cancers. The women had a lower risk for several cancer types including pancreatic, liver, lung and breast cancer.
Not all dust is protective. For example, workers in paper mills are at greater than average risk for cancer. This increase might be due to the dust or because of exposure to some chemicals used in the mill. Similar increased risk occurs in hard-metal workers.
One unexpected way to trigger the immune system to prevent cancer is through vaccines. Klaus Kolmel of the University of Gottingen has written some fascinating papers about this. He has concluded that Vaccinia (the virus that was once used to vaccinate against smallpox) and the BCG vaccine used against tuberculosis had a protective effect. He and his colleagues had produced a series of papers that suggest childhood vaccinations protect those who got them decades later from cancer. I say had because these vaccines rarely are given these days.
In a 2002 paper, Kolmel compared vaccinations received by 603 people diagnosed with melanoma with those of 627 controls. The people given the TB vaccine, the smallpox vaccine or both, were less likely to develop melanoma (overall risk 0.44). For people less than 50 years old, the protective effect was stronger. The risk dropped by a factor of four, suggesting the cancer protective effect of the vaccines weakens with age.
In 2003, Kolmel published data suggesting that vaccination against tuberculosis lowers the risk of leukemia. Here's where it gets interesting. Using the same people as in the 2002 paper, Kolmel published a paper in 2003 examining the combined effect of vaccination and a feverish illness as protecting against cancer. The risk of developing melanoma decreased by 63 percent if someone had experienced a high fever (>38.5 C or >101.3 F). If they had a fever and also had been vaccinated either against TB or smallpox, their risk of melanoma dropped even further; a decrease of 71 percent compared to those who were unvaccinated and had not experienced high fevers. Not only did the vaccinations protect against getting melanoma, if vaccinated people were unlucky enough to get melanoma, they had a smaller chance of dying from it than their unvaccinated counterparts. Only people who received the vaccine as babies appeared to gain protection. Vaccinating patients already diagnosed with melanoma appears to be too late to help.
Other vaccines also might provide benefit. No one has yet run studies to ask if they do. The simplest explanation as to why these vaccines provide such long-lasting protection against cancer goes back to that same endotoxin exposure theory used to explain how manure and cotton exposure provides protection.
There is little argument that the immune system can provide protection against cancer. The immunosuppressant drugs used by organ transplant patients increase their risk of getting melanoma by 300-400 percent. Lin Zhang of the University of Pennsylvania in Philadelphia reported in 2003 that patients whose ovarian tumors contained immune cells had a 38 percent chance of surviving at least five years, compared with just 5 percent for those whose tumors contained none.
It also might be that endotoxins act as an adjuvant. An adjuvant is a substance added to vaccines that increases the strength of the immune response. The main portion of a vaccine is a protein specifically isolated from the disease that teaches the immune to recognize that specific disease-causing agent. The adjuvant makes the immune system wake up and pay attention. Vaccine makers have long known that adding an adjuvant will create a stronger response. The immune system already might recognize the tumor cells, but it takes the adjuvant, in these cases the endotoxins or the vaccines, to trigger these immune cells to actually attack the cancer.
Another theory to explain all this is that infections balance immune- system function. Exposure to various infections and triggers keeps the immune system functioning better. Then there is this business about fever. Any mention of fevers and cancer has to mention Coley toxins. In the 1890s, an American doctor named William Coley started treating cancer by inducing fevers with bacterial preparations. He injected these mixtures directly into the tumors until the patient spiked a fever. Apparently, if the patient survived the infection and the fever, they had an improved chance of surviving the cancer. This story is interesting, but I'm going to skip it now and write about it in detail in the future.
Kolmel's data suggest that fever lowers melanoma risk. Cancer cells are more vulnerable to heat than normal cells. Dying cancer cells produce extra antigen that is recognized by the immune system. There might be a more specific mechanism going on in melanoma to explain this. Whether or not someone develops melanoma apparently depends on an ancient viral gene in our genome. We carry genetic material from some retroviruses in our genes. They are referred to as human endogenous retroviruses (HERVs), and they are linked to developing some cancers.
The HERV genes get turned on in certain cancers. Melanoma cells produce lots of a protein called HERV-K-MEL. The TB bacterium, the Vaccinia virus and other pathogens all produce proteins containing very similar sequences to HERV-K-MEL. A colleague of Kolmel has proposed that the immune response to the pathogens in the vaccines also could trigger an attack on cells producing HERV-K-MEL. None of this is fool-proof; vaccines, fever, cotton or manure don't protect against all cancers. It is even possible that some cancers could increase. As I've written before, biology tends to be messy.
I'm reminded of a recent article that is probably interesting only to certain minds. John Kappelman, from the University of Texas, wrote about finding a chunk of human-like skull preserved in a piece of Turkish tile. The skull dates back half a million years. Although the fragment was small, scientists were able to determine the original owner suffered from tuberculosis.
Our kind has been living with tuberculosis for a long time and it's not so outlandish to think our immune systems need a dose of TB to be at their best. Of course, this paper also suggests the next time you are shopping for tile at Home Depot, look carefully; you never know what you will find.
Smallpox vaccination was stopped in the 1970s (except for U.S. military personnel who started getting it again in 2002). The BCG vaccine was stopped in many countries in the 1990s. BCG was never used in the U.S.
It's predicted that the protective effect against melanoma provided by these vaccines will wear off around 2010 as people who were born after these vaccines get old enough to develop melanoma. We should hope these theories prove wrong or else we might see an unexplained surge in the number of cases of melanoma in the next few years.
About the Author: Dr. Jacob Schor graduated with a bachelor of science degree from Cornell University and received his naturopathic training at National College of Naturopathic Medicine. He currently practices at the Denver Naturopathic Clinic. E-mail Dr. Schor at firstname.lastname@example.org.
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All Rights Reserved, Naturopathy Digest, 2011.
Date Last Modified - Friday, 17-Oct-2008 12:11:18 PDT