Definition/Components: The immune system protects the body from pathological bacteria, foreign cells, cancerous cells and certain infectious diseases. This defense system begins with the skin and mucosa, which is the body’s first barrier of protection. Both produce antimicrobial secretions which are found in saliva and in tears. When a foreign substance passes through the skin an immune response is initiated. Then efforts to neutralize the invader occur with the help of very specialized cells and molecules. Cells that take part in this response are lymphocytes, (white blood cells formed in lymph nodes which help to produce antibodies; there are two types: B and T lymphocytes), and macrophages (a type of lymphocyte that ingests foreign substances and is either fixed or wandering). Other components of the immune system are: substances released from lymphocytes (antibodies), complement (part of blood plasma), and other cell types and substances. Moreover, there are several organs that belong to the immune system; they are the thymus (this organ produces lymphocytes that are ready to engage to immunological needs), the spleen, and the tonsils.
Action of Immune System: Once inside the internal tissues, the invader is selected by the lymph and carried into the lymphatic system, a group of interconnected lymph nodes which are located throughout the body. Each lymph node contains specialized immunological cells which engage in the battle to detect and eradicate invading agents; this is part of our immune response, of which there are any several types of responses depending on what type of defense is needed. But with the advent of pesticides our immune system is being challenged often unbeknownst to unsuspecting consumers.
Moreover, pesticide use is so widespread and increasing, it is becoming apparent that serious adverse heath effects on humans, animals, and the environment are the direct result of exposure. And while it is important to be concerned with many of the disease states that are linked with pesticides, there are other risks as well, that are not as obvious, but could be much more sinister than we realize. That is, evidence suggests strongly that our immune system, which is our body’s line of defense against disease, is being compromised (weakened) due to the toxic nature of pesticides. Without a strong immune system we cannot effectively protect our bodies from both external and internal invaders, such as fight bacteria, viruses, parasites, or abnormal cell growth (both benign and malignant tumors) leaving us vulnerable to the ravages of disease.
Pesticides cause immunosuppression. Without an effective immune system, people are considered immunosuppressed. Immune suppression can occur for a variety of reasons such as chemotherapy, certain disease states, such as cancer. Likewise, immune suppression can result from the variety of solvents, inert ingredients, and other ingredients and contaminants that comprise pesticide mixtures. And it is this resulting immune suppression that may also play a key role in the development of certain cancers. Take for example a particular group of people, farmers; that are often test subjects for studies on pesticides; they are heavily exposed to pesticides and their rates cancer exceed the general population. Moreover, they are more likely to have Hodgkin’s disease (lymphoma), multiple melanoma, myeloma, and leukemia; these are all cancers of the immune system. The same holds true for increased cancer rates among those who dwell near agricultural areas where crops are routinely sprayed with pesticides.
The limits of Research and the Promise: Research studies on animals indicate that a variety of pesticides do suppress mammalian immune systems. While the studies are not conducted on humans, the results obtained from animal models are relevant since the immune system of both mammals and man are similar structurally. But despite some pretty convincing evidence, research studies that focus on the effects of pesticides and their immunosuppressive properties are not without issue. For example: little work has been completed that elucidate the relationship between a particular individual pesticide dose and its accompanying effect. That, is we still don’t know how much of a pesticide is required to exert a devastating effect on a person’s immune system, enough to induce not just weakness and vulnerability, but trigger a disease state, like cancer. Additionally, we are only starting to understand what chronic low dose (or short dose) exposure to pesticides might do. Likewise we need to understand, over time, what the accumulative effect in the body might be, which will also tell us, if pesticides can have a detrimental effect on a person’s immune system.
The following list will provide adequate evidence that exposure to common pesticides is, in fact, is not only damaging our immunes systems, but weakening our body’s ability to fight infectious disease or remain free of cancer. This list compliments the research summaries we have provided in this report. Additionally, all the entries below are taken from a work sheet entitled: Pesticides And The Immune System – Overview, which presents highlights of Dr. Robert Repetto and Sanjay Baliga’s book: Pesticides And The Immune System: The Public Health Risks. The pages are referenced.
 Studies utilizing accepted scientific methods demonstrate that pesticides change an animal’s immune system. Pesticides evidently reduce disease not only the population of disease fighting white blood cells called lymphocytes, but seem to impair their role as bacterial and viral killers. Key developmental changes have been observed in both the liver and spleen which are immune system organs. (p.21).
 Both Canadian and former Soviet Union epidemiological studies have revealed that children and adults after pesticide exposure develop impaired immune systems increasing their susceptibility to infectious disease. Pesticide induced immunosuppression impacts infants and children especially as well as the elderly, those who are chronically ill and malnourished more seriously. (p.18 and 56)
 Restrictions and or bans on certain pesticides utilized in both the former European Union (EU) and here in America have occurred because of tests that reveal they are acutely toxic and are associated with a significant cancer risk. Unfortunately, many of these pesticides are freely used in developing countries including the former Soviet Union. (p.4)
 Pesticides increase a person’s likelihood of developing certain cancers as pesticides weaken your immune system and its ability to fight/detect against cancer cells.
 “Farmers generally have lower risks of cancer than other men, but have a higher risk for the kinds of cancers found in immune-deficient patients (those with AIDS and those taking immuno-suppressive drugs): Hodgkin’s disease, multiple myeloma, leukemia (all cancers of the immune system) and cancers of the lip, stomach, and prostate. Farmers most heavily exposed to pesticides have the highest relative rates.” (p.41-42).
 “Russian research in the cotton, tobacco, and vegetable-growing regions of Samarkand found that people exposed to organo-chloride and organo-phosphate pesticides harbored auto-immune antibodies. Factory workers elsewhere in Russia showed similar symptoms.” (p.44) Note: Some pesticides are associated with the development of auto-immune antibodies, where the body attacks itself, this is a good example of an altered immune system, the end result, of which is the possible trigger of an autoimmune disease. Antibodies are substances that naturally occur in the body; they attack foreign substances (i.e. bacteria).
Throughout our report we have included research summaries of laboratory studies that clearly demonstrate that a number of pesticides tend to increase a person’s risk of developing a particular disease and/or underlying medical condition such as infertility, birth defects and a variety of other reproductive health issues. Diseases range from asthma, brain cancer, breast cancer, to leukemia (both child and adult), lymphoma (non-Hodgkin’s), Parkinson’s disease, to uterine cancer, etc. More recently, even depression and diabetes has been linked to pesticide exposure.