The immune system is your body’s defense against intruding foreign organisms that cause disease. White blood cells called leukocytes seek out and destroy threatening organisms.
Chemotherapy and treatments to prevent rejection of grafts or transplants or control autoimmune diseases can suppress or weaken the immune system. Hematological cancers, such as leukemia, suppress normal immune system function.
You can inherit a genetic conditon that weakens your immune system. Collectively, this is called immunosuppression.
The Immune System
In order to comprehend the significance of immunosuppression, it is important to understand how the immune system functions.
The immune system is made up of white blood cells called leukocytes, which are produce and stored in many locations including the thymus, spleen and bone marrow.
Lymphoid tissue, primarily the lymph nodes, store leukocytes. Leukocytes circulate through the body between the organs and lymph nodes via blood vessels and lymphatic vessels. They continuously monitor for harmful germs and substances.
The two basic types of leukocytes are phagocytes, which digest the invading organisms, and lymphocytes. Bone marrow and the thymus are called lymphoid organs, because they store lymphocytes. Both are organs of the immune system. The two types of lymphocytes are B and T lymphocytes.
B lymphocytes remain in the bone marrow and produce antibodies. T lymphocytes leave the bone marrow and travel to the thymus. They destroy antigens identified by the antibodies or cells that have become infected or altered. (1)
The Immune Response
A healthy immune system distinguishes the body’s own cells from foreign cells. But, when foreign intruders, called antigens, are detected, the immune system attacks. This is called the immune response. An antigen is any substance that can trigger the immune response.
Viruses, bacteria, tissue grafts and organ transplants acts as foreign antigens. In some situations, allergens such as tree pollen, triggers an immune response. In abnormal circumstances, the immune system mistakenly identifies the body’s own cells as foreign and launches an attack The result is called an autoimmune disease. (2)
Causes and Consequences of Immunosuppression
Common variable immunodeficiency is the most common inherited cause of immunosuppression. It is a condition in which the body cannot produce antibodies to fight infections. The age of onset is the 20s and 30s but rarely before the age of six.
Individuals often experience recurrent infections, particularly of the respiratory tract, develop autoimmune disorders, such as rheumatoid arthritis, and have an increased risk for developing certain cancers, such as gastric carcinoma and lymphoma. (3)
Chronic lymphocytic leukemia and lymphoma are two types of blood cancer in which lymphocytes reproduce uncontrollably and outnumber normal cells. Multiple myeloma is a cancer of the plasma cells, which produce antibodies.
The cancerous plasma cells reproduce uncontrollably and increase the number of plasma cells to a higher than normal level. Increased risk for infection is associated with these three hematological cancers. (4,5, 6, 7)
Chemotherapy medications, such as Cisplatin, Cyclophosphamide and Vinblastine, work by killing fast-growing cancer cells. However, these myelosuppressive drugs also suppress the production of white blood cells.
Neutropenia is a potential side effect. Abnormally low levels of neutrophils, a specific type of white blood cell, puts patients receiving chemotherapy at high risk for developing infections. (8)
Medications, such as Interferons and Methotrexate, are prescribed to control autoimmune disorders. Medications like Tacrolimus are used to prevent the rejection of transplanted organs. Immunosuppression is a side effects of these types of medications. (4)
Coping with Immunosuppression
There are measures you can take to reduce your risk of infection. Getting enough protein in your diet helps keep the immune system strong. Lean meats, fish, eggs and pasteurized tofu are good sources of protein. It is very important to check the internal temperature of these foods with a thermometer to be sure it is at the correct temperature to kill bacteria.
Avoid eating raw vegetable sprouts, raw eggs, unpasteurized eggnog, uncooked dishes containing eggs, such as Caesar salad dressing, unpasteurized fruit and vegetable juices such as cider, raw or uncooked meat, poultry and shellfish and tofu packed in water. It is wise to avoid soft cheeses such as feta and brie, raw honey, sun tea and unpasteurized beer. (9)
Wash your hands frequently, especially after using the bathroom, before eating and when handling food. Avoid eating foods from salad bars, buffets and sidewalk vendors. Avoid crowded situations, especially during peak influenza season. Take a daily multivitamin.
(1) KidsHealth from Nemours: Immune System, Nov. 2, 2011
(2) NIAID Science Education @ National Institute of Allergy and Infectious Diseases:
Understanding the Immune System/ How it Works. Nov. 2, 2011
(3) PEDBASE.org: Common Variable Immunodeficiency (CVID), Nov. 3, 2011
(4) The Merck Manual: Appendix II: The Immunosuppressed Patient, Nov. 3, 2011
(5) Lab Tests Online: Lymphoma, Nov. 3, 2011
(6) Mayo Clinic: Chronic Lymphatic Leukemia, Nov. 3, 2011
(7) Mayo Clinic: Multiple Myeloma, Nov. 3, 2011
(8) Neulasta: About Low White Blood Cell Counts, Nov. 3, 2011
(9) BreastCancer.org: Eating When You Have a Weakened Immune System, Nov. 6, 2011
Reviewed November 7, 2011
by Michele Blacksberg RN
Edited by Jody Smith