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Your amazing immune system battles for your life every day

Have you ever wondered why a child can pick up candy off the floor, eat it and not get sick? Or, why you could step into an elevator, bus or plane filled with sneezing, coughing people and go home cold free? It's because your immune system is at work. At this second, it is waging a silent war against billions of harmful bacteria, viruses, pathogens, fungi and parasites that could threaten your survival at any time.

How does the immune system work?
Martin Topiel, MD, chief of infectious diseases at Virtua Memorial Hospital explains: “Immunity is a highly evolved, astonishingly sophisticated defense system of cells and organs. Together they work to recognize foreign invaders or antigens and to react against them. Each time a foreign substance enters our bodies the immune system mobilizes and creates antibodies to fight off the offending substances.”

Your immune response starts here
The first line of defense against many bacteria or viruses is the skin, our largest organ and a nearly impenetrable physical barrier. Supporting the skin are the fine hairs that line the nose and the secretions from the mucous membranes in the mouth, stomach and intestines. Their job is to trap or kill bacteria or viruses before they multiple or make us seriously ill. These natural immune mechanisms hinder the entrance and spread of disease but can't prevent disease completely.

If an invader gets past these barriers, our lymph nodes remove the bacteria and foreign particles from the body. Found on the sides of the neck, under the arms, in the groin area as well as internally, lymph nodes also supply the bloodstream with lymphocytes. These are the cells that develop our immunity toward harmful invaders. Some lymphocytes, called B cells, attach themselves to foreign substances and serve as a marker for other immune cells to step in and kill them. Another class of lymphocytes, T cells, create a cytotoxic reaction — directly attacking and destroying cells they recognize as harmful. While greatly simplified, all of this helps our bodies to ward off illnesses that range from colds, flu and SARS to tuberculosis, hepatitis, and HIV.

A malfunction of the immune system
While the immune system is an extraordinarily sophisticated mechanism, it can go haywire and cause a variety of disorders and diseases. One of the most familiar is allergy. This occurs when our system responds to a false alarm – to substances that are not inherently harmful such as shrimp, cats or ragweed.

Stanley Lane, MD, chief of allergy at Virtua Memorial Hospital explains: “In an allergic reaction, the body mistakenly treats the offending pollen, pet dander or peanut as an invader and mobilizes to attack. It generates large amounts of a type of antibody called immunoglobin E. This, in turn, releases histamines that cause sneezing, itching and wheezing. In an anaphylactic reaction, a massive — even life threatening — amount of histamines are released.”

Sometimes the immune system breaks down and recognizes its own cells and organs as foreign or an invader. This is called autoimmune disease, a condition in which the body creates antibodies against itself. Rheumatoid arthritis is an example. There are also times when the immune system lacks one or more of its components, resulting in immunodeficiency disorders such as AIDS.

Mobilizing the immune system to fight cancer
Another important job of our immune system is to patrol our cells for developing malignancies. Sometimes, the process breaks down and fails to stop the growth of cancer cells. Researchers are now working on new approaches to cancer treatment that use antibodies to enhance the immune system.

“Immunotherapy is the most advanced cancer treatment available,” says Alan Weinstein, MD, medical and administrative director, Fox Chase Virtua Health Cancer Program at Memorial Hospital. “One form uses interferon, a naturally occurring substance which, some data has shown, can heighten the body’s own immune response against cancer cells. Interferons are FDA-approved for the treatment of melanoma, a serious form of skin cancer and certain types of leukemia."

Another type of immunotherapy is monoclonal antibody therapy — laboratory-produced antibodies designed to attach to a certain part of cancer cells and disable them. When a radioactive isotope is combined with the antibody, a lethal dose of radiation is delivered to the cancer cells. This highly targeted approach minimizes damage to surrounding cells and organs. Rituxan and Zevalin therapy are new monoclonal antibody therapies for low-grade, non-Hodgkin’s lymphoma, and are available through the Fox Chase Virtua Health Cancer Program.

Dr. Topiel says: “The real miracle of our immune systems is the fact that we don’t become ill more often — and that so many of us live long, productive, relatively healthy lives.”