Normal and Poor Immune System

The immune system comprises from immune cells, like white blood cells, antibodies and other substances that fight against microbes and thus defend us against infections.

We may suspect that our immune system is low (poor, weak, deficient) when we suffer from frequent infections (like having influenza several times a year), when infections heal slowly (like common cold lasting a month), when they affect unusual sites (like Candida albicans yeast appearing in the mouth) or infections that usually do not affect people with normal immunity (like Pneumocystis carinii fungus is harmless for healthy people but can cause pneumonia in AIDS patients).

People with chronic diseases, like diabetes or cancer, or those exhausted from long lasting hard work, starvation or  psychological stress may also have lowered immunity and therefore frequent infections. Because of stress or disease, an old herpetic infection may re-activate and appear as oral herpes (itchy blisters around the mouth), genital herpes (on genital mucosa) or shingles (rash in a band-like distribution, affecting one side of the trunk, limbs or face). 

When we know exact substance, like chemotherapy drugs or steroids, which causes low immunity, we say that immune system is suppressed or compromised.

A term immune deficiency is usually reserved for severely weakened immunity, which may be temporary, like most of acquired immune deficiences, or permanent, like most of hereditary immune deficiences and AIDS.

Diagnosis of Low Immunity

When low immunity is suspected, amount of immune cells (leukocytes and their subtypes: neutrofils, eosinophils and lymphocytes), antibodies (immunoglobulins, especially IgG and IgM) and complement (special proteins contributing in immunity) in the blood have to be checked.

Treatment of the cause, if possible and successful, usually results in normal immunity. If chemotherapy drugs or steroids severely affect immunity, they should be discontinued but only with doctor’s approval. In AIDS, which can not be treated for now, avoiding of infections is extremely important.  In certain hereditary immune deficiences, components of immune system, like immunoglobulins, can be injected intravenously, or transplantation of bone marrow, from which immune cells may grow, can be done.

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Article reviewed by Dr. Greg. Last updated on December 1, 2009