Weakened Immune System

Weakened immune system is a quite popular term in modern society that is in my opinion a little bit overused. The immune system is a highly complex mechanism consisting of mutually coordinated actions of defense cells (neutrophils, lymphocytes, macrophages and many others) and various protein substances (complement, antibodies, etc.). These reactions lead to targeting, labeling and disposal of foreign substances, foreign cells and in addition also of body own cells that are no longer under its control mechanisms (cancer cells). Main result of immune system disruption is obvious - poor ability to fight infections. This results not only in frequent infections, but also in disability to defend against common and otherwise relatively benign microorganisms. In addition, long-term immunocompromised patients have higher incidence of malignant diseases.


There are many possible causes of immune system weakening. We can distinguish congenital and acquired disorders. Congenital disorders are very rare and they manifest by frequent infections in childhood. This article is dedicated to acquired immune disorders that develop during life. Their number rapidly grows mainly because of increasing AIDS occurrence and use of immunosuppressive drugs.

Immunosuppressive drugs

There is a wide range of drugs that suppress the immune system. These drugs are used in therapy of inflammation conditions, autoimmune diseases and after organ transplants to prevent transplant rejection. Corticosteroids are probably the most often used drugs of this group while so-called biological therapy represents more modern (and expensive) group of drugs.


The HIV infection affects some types of lymphocytes that are essential in coordination of global immune response. When those lymphocyte numbers drop under certain level, AIDS occur accompanied with immunodeficiency.


Patients with diabetes have worse function of immune system. Apart from that, elevated level of blood sugar (glucose) and sugar presence in urine cause more frequent bacterial infections as glucose is a welcome bacterial food.

"Blood tumors"

These diseases include for example leukemia, lymphoma and multiple myeloma. Although many of these diseases cause uncontrolled proliferation of white blood cells, these malignant cells are non-functional. In addition tumor cells invade blood marrow and suppress production of healthy blood cells. The result may be severe deterioration of immune system.

Inadequate nutrition

Insufficient supply of nutrients, especially protein and vitamin deficiency, has an adverse effect on the immune system. Proteins are essential components of the immune system and their deficiency disrupts its function very seriously. Negative effect has also the absence of certain trace elements such as selenium.


Advanced age is associated with a gradual deterioration of organism including its immune system. It is an irreversible and natural process of aging.

Chronic stress

While acute stress condition can have many positive effects, long-term stress is demonstrably harmful to our organism. Immune system may be affected either by suppression or inadequate strong activation leading to autoimmune reactions.

Jiri Stefanek, MD  Author of texts: Jiri Stefanek, MD
 Contact: jiri.stefanek@seznam.cz
 Sources: basic text sources