Peyer's Patches

Named for the seventeenth century Swiss anatomist, Hans Conrad Peyer, Peyer's patches are a collection of large oval lymph tissues that are located in the mucus-secreting lining of the human small intestine. These lymph nodules are especially abundant in the ileum, the lowest portion of the small intestine.

Peyer's patches are more numerous in younger individuals and become less prominent with age. Approximately 30 to 40 patches or bundles occur in an individual's intestine, and they appear as elongated thickened areas lacking the villi that are typical of intestinal membrane. However, because they are composed of networking tissues, the nodules are not easily distinguished from surrounding connective tissue.

The lymph system and associated tissues and structures present a strong line of defense against invading bacteria, parasitic microbes, viruses, and other foreign or harmful bodies such as cancer cells. The Peyer's patches contain high concentrations of white blood cells (or lymphocytes) that help protect the body from infection and disease. Because mucus-secreting surfaces of almost any organ, but especially the digestive, genital, and respiratory tracts, are constantly exposed to a wide variety of harmful microorganisms, they are supported by secondary lymph structures. The specialized lymphoid tissues in the small intestine, Peyer's patches, detect antigens such as bacteria and toxins and mobilize highly specialized white blood cells termed B-cells to produce protein structures called antibodies that are designed to attack foreign entities.


Inadequately digested food molecules, not digested well enough to be absorbed across the gut wall, are acted upon by "unfriendly" bacterial growth in the bowel. When this happens, toxic chemicals, known collectively as "Indican," are formed. Most of these compounds can be excreted in the feces. However, since they are toxic, they cause a number of problems, not the least of which is inflammation of the bowel.

Unfortunately, the patient is usually only aware of increased lower bowel gas and constipation. These symptoms of putrefaction are usually dismissed and only if they continue are over-the-counter remedies purchased. Seldom is a doctor consulted.

This process has been widely underestimated as a stressor of the immune system. It is the function of the phagocytic cells found in Peyer's patches and other lymphatic aggregate follicles, to attack these foreign invaders while they are still in the bowel.

When the intestinal mucosa becomes inflamed it becomes more permeable. When the functioning of any aspect of the gut mucosal barrier is sufficiently compromised, the integrity of the bowel itself becomes compromised, resulting in increased permeability to foreign or gut-derived antigens, allowing them to "leak" through the gut into the lymphatics and the systemic circulation.

Obviously, once they have entered the blood they are no longer subjected to the action of the digestive tract and must be eliminated by the immune system. Acting as foreign invaders, they can target specific organs, produce pain, and an inflammatory immune response. This process is enhanced by the deposition of immune complexes in the tissues.

The union between these remnants and the phagocytic cells have been referred to as circulating immune complexes. This can lead to the symptoms of fibromyalgia as well as symptoms of infection, even without an infectious agent, because immune responses to foreign invaders are identical, be they infectious or not.

Circulating immune complexes (systemic foreign antigens) are the leading cause of fibromyalgia and can retard healing, promote and prolong pain from inflammatory processes and reduce the competency of the immune system. Only an intact intestinal mucosal barrier protects the body from entry by foreign antigens and their systemic effects.

Therapy with prostaglandin inhibitors such as Nsaids or aspirin, and steroids such as prednisone and cortisone are the major factors that compromise the mucosal barrier. Prostaglandin inhibitors suppress repair and have been shown to increase gut permeability with moderate use. Long-term steroid use can cause stomach and duodenal ulcers and immune suppression contributing significantly to gut hyperpermeability and its complications.

Antacids decrease the acidity of the stomach, reduce the activity of pepsin and limit the stomach's ability to adequately digest proteins. This compromise increases the number of undigested, large molecules entering the bowel and systemic circulation. By decreasing stomach acidity, antacids can also impair the absorption of minerals.

Antibiotics disrupt the normal balance of bacterial microflora in the gut, as well as the mouth, skin and vagina. This often leads to serious overgrowth of pathogenic microflora in these areas resulting in infection and inflammation. Proliferation and overgrowth of Candida and other yeasts in the gastrointestinal tract can result in a complex of symptoms from gas, bloating and gastrointestinal distress to unexplained chronic fatigue, depression and various systemic inflammatory disorders.


  • Cynthia D. Kelly, Thomas J. Fellers and Michael W. Davidson - National High Magnetic Field Laboratory, 1800 East Paul Dirac Dr., The Florida State University, Tallahassee, Florida, 32310.

  • (Dr. Loomis welcomes input on the subjects covered in this column. To make a comment, or ask a question, write to him at 6421 Enterprise Lane, Madison, WI 53719. Or, call 800-662-2630.)


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