Immune Function and the Lymphatic System


The lymphatic system is a collective name for the various lymph tissues and cells in the body.  The central lymph tissues include the thymus gland, the bone marrow, the lymph nodes, the spleen and tonsils, and compartments found behind the epithelial layer of the gastrointestinal mucosa called gut associated lymphoid tissue (GALT).

Understanding of the importance of lymph tissue in immunological function throughout the body is gradually increasing, with researchers focussing on the functions of LALT (larynx-associated lymphoid tissue), MALT (mucosa-associated lymphoid tissue), and VALT (vascular-associated lymphoid tissue). I think of these lymph tissues as immune governments or police stations, where lymphocytes go to get their orders, identify criminals, coordinate activities, transmit information and receive nutritional paychecks.

Lymph System Components

Lymph is a clear, colorless, alkaline fluid that circulates through body along our lymph vessels. TAM doctors call lymph “sweet water.” The liver produces about one third of the lymph, and the intestine another sixth. The rest is produced in tissue spaces throughout the body.

The lymph vessels contain filtration nodes where immune system cells gather to destroy foreign bodies, especially bacteria and cancer cells. They also drain the villi in the intestinal tract.  Tiny lymph capillaries originate in distant parts of the body, and form into lymph vessels as they flow, in one direction only. The vessels get larger as they move toward the center of the body, finally converging into the large thoracic lymph duct which emptys into the largest vein in the body, the vena cava.

Thymus Gland

The thymus gland is a soft pinkish-gray gland that sits above the heart and serves as the maturation host for T-cells.  It helps in the production of T lymphocytes, strong white blood cells that help the body resist infection by bacteria, fungus and viruses. The thymus also secretes hormones that regulate immune function. The thymus gland requires a sufficient supply of zinc in order to function properly. Oysters are a rich source of this mineral, providing approximately 150 mg. in a 3.5-oz serving.

Many herbs have been shown to enhance thymus activity, including echinacea, ginseng root, neem leaf, Siberian ginseng root bark and licorice root.  Herbs containing triterpenoid saponins also generally stimulate the thymus gland. These herbs include ganoderma and poria mushrooms, ginseng root, bupleurum root and licorice, as well as herbs found in many Yin tonics for the lung, such as opiopogon and anemarrhena rhizome (zhi mu or Anemarrhena asphodeloides). (Kim YR et al., 1999,  Nanahoshi M., 1967, Plohmann B et al., 1997, Ray A et al., 1996, Dharmananda, 1998)

GALT

The most voluminous lymph-related (lymphoid) organ in the body is the GALT or gut-associated lymphoid tissue. This tissue is a separate mesoderm-derived compartment located directly behind your intestinal membranes, and its function is to maintain a diverse population of healthy lymphocytes capable of responding to the enormous numbers of antigen s that enter your body every time you eat. Special M-cells efficiently envelop these macromolecules and microorganisms from the intestine and deliver them to the underlying GALT.  This process produces a huge quantity of immunoglobulins, which are necessary for your immune system to properly tag each and decide whether to allow it safe passage (tolerance) or mark it for destruction. Think of the GALT as your body’s Immigration and Naturalization Service. (Miura S et al., 1998, Mayer L, 2000, Niedergang, 2000, Pulverer et al., 1997)

According to an article appearing in the Journal of the American Medical Association, problems in the GALT have been associated with “inflammatory bowel disease, Whipple disease, autoimmune gastritis, Helicobacter pylori infection, immunoproliferative small intestinal disease, hepatitis A, B, C, D, E, F, and G, autoimmune hepatitis, primary biliary cirrhosis, progressive sclerosing cholangitis, and vanishing bile duct syndrome” (Galperin and Gershwin, 1997).

GALT health is maintained with methods such as use of castor oil packs, carotenoids, vitamin B-complex, vitamin A, avoiding food you are allergic to, healthy diet, and attention to proper digestion and elimination.

Spleen

The spleen is the “heart” of the lymph system. It is a filtration organ, and participates in immune response to blood borne pathogens.  It is the site where the body traps and digests upwards of 50% of all dying red blood cells and platelets.  The spleen also serves as a blood reservoir, for both phagocytic cells and lymphoid cells, releasing blood cells in cases of sudden blood loss or infection. Spleen problems are almost always secondary to other systemic problems, and the main symptom is enlargement. This usually resolves as the causative problems are treated.

As a general rule for treating the spleen, 60-70% of your main formula should focus on the specific causative factor. Additionally 30-40%% can include herbs specifically for the secondary spleen enlargement. Ayurvedic doctors use shilajatu, eclipta, rohitaka stem (Rhododendron arboreum), hemaksiri (Argemone mexicana)  and condensed aloe gum for spleen enlargement.  TCM doctors use moving blood herbs, especially tortoise shell (gui ban), zedoaria root (e zhu or Curcuma zedoaria) , salvia root and prepared rhubarb root. Western herbalists use milk thistle seed, blue flag root (Iris versicolor), red root (Ceanothus americanus), barberry root bark (Berberis vulgaris), bear’s foot leaf or root (Polymnia uvedalia), and dandelion root.

Tonsils
The tonsils, a mass of lymphatic tissue, are located on the sides of the throat. Like all lymph components, the tonsils act as a filter, and aid in the formation of white blood cells. The close-by adenoids act in a similar way.
Echinacea, honeysuckle flower (jin yin hua or Lonicera japonica), forsythia fruit (Lian qiao or F. suspensa), isatis root and leaf (very effective), white sage (Salvia apiana), and elderberry are effective treatments for infected tonsils.  Drinking tea high in tannin concentration can be useful. Fresh or dried honeysuckle flower tea with honey is a pleasant and palatable tonsil treatment.