3. • Immunodeficiency disorders involve
• malfunction of the immune system, resulting in infections that
develop and recur more frequently, are more severe, and last
longer than usual.
4.
5. • Immunodeficiency disorders impair the immune system’s ability to
defend the body against foreign or abnormal cells that invade or attack
it (such as bacteria, viruses, fungi, and cancer cells). As a result,
unusual bacterial, viral, or fungal infections or lymphomas or other
cancers may develop.
• Another problem is that up to 25% of people who have an
immunodeficiency disorder also have an autoimmune disorder (such
as immune thrombocytopenia). In an autoimmune disorder, the
immune system attacks the body's own tissues. Sometimes the
autoimmune disorder develops before the immunodeficiency causes
any symptoms.
6. There are two types of
immunodeficiency disorders:
• Primary: These disorders are usually present at birth and are genetic
disorders that are usually hereditary. They typically become evident during
infancy or childhood. However, some primary immunodeficiency disorders
(such as common variable immunodeficiency) are not recognized until
adulthood. There are more than 100 primary immunodeficiency disorders. All
are relatively rare.
• Secondary: These disorders generally develop later in life and often result
from use of certain medications or from another disorder, such
as diabetes or human immunodeficiency virus (HIV) infection. They are more
common than primary immunodeficiency disorders.
• Some immunodeficiency disorders shorten life span. Others persist
throughout life but do not affect life span, and a few resolve with or without
treatment.
7. Causes of Immunodeficiency Disorders
• Primary immunodeficiency
• Primary immunodeficiency disorders may be caused by mutations,
sometimes in a specific gene. If the mutated gene is on the X (sex)
chromosome, the resulting disorder is called an X-linked disorder. X-
linked disorders occur more often in boys. About 60% of people with
primary immunodeficiency disorders are male.
8. • Primary immunodeficiency disorders are classified by which part of the immune system is affected:
• Humoral immunity, which involves B cells (lymphocytes), a type of white blood cell that produces antibodies
(immunoglobulins)
• Cellular immunity, which involves T cells (lymphocytes), a type of white blood cell that helps identify and destroy
foreign or abnormal cells
• Both humoral and cellular immunity (B cells and T cells)
• Phagocytes (cells that ingest and kill microorganisms)
• Complement proteins (proteins that help immune cells kill bacteria and identify foreign cells to destroy)
• The affected component of the immune system may be missing, reduced in number, or abnormal and
malfunctioning.
• Problems with B cells are the most common primary immunodeficiency disorders, accounting for more than half.
9. Secondary immunodeficiency disorders
• These disorders can result from
• Prolonged (chronic) and/or serious disorders such as diabetes or cancer
• Drugs
• Rarely, radiation therapy
• For example, diabetes can result in an immunodeficiency disorder because
white blood cells do not function well when the blood sugar level is
high. Human immunodeficiency virus (HIV) infection results in acquired
immunodeficiency syndrome (AIDS), the most common severe acquired
immunodeficiency disorder.
10. • Many types of cancer can cause an immunodeficiency disorder. For
example, any cancer that affects the bone marrow (such
as leukemia or lymphoma) can prevent the bone marrow from
producing normal white blood cells (B cells and T cells), which are part
of the immune system.
• Undernutrition—whether of all nutrients or only one—can impair the
immune system. When undernutrition causes weight to decrease to
less than 80% of recommended weight, the immune system is often
impaired. A decrease to less than 70% usually results in severe
impairment.
11. Immunodeficiency in older people
• As people age, the immune system becomes less effective in several
ways (see Effects of Aging on the Immune System). For example, as
people age, they produce fewer T cells. T cells help the body recognize
and fight foreign or abnormal cells.
• Undernutrition,
• Two nutrients that are particularly important to immunity—calcium and
zinc—may be deficient in older people.
• Certain disorders (such as diabetes and chronic kidney disease), and
certain therapies (such as immunosuppressants), can also impair the
immune system.
12. Symptoms of Immunodeficiency
Disorders
• People with an immunodeficiency disorder tend to have one infection after another.
Usually, respiratory infections (such as sinus and lung infections) develop first and recur
often
• severe bacterial infections that persist, recur, or lead to complications. For example, sore
throats and head colds may progress to pneumonia.
• Infections of the mouth, eyes, and digestive tract are common. Thrush, a fungal infection
of the mouth, may be an early sign of an immunodeficiency disorder. Sores may form in
the mouth. People may have chronic gum disease (gingivitis) and frequent ear and skin
infections. Bacterial infections (for example, with staphylococci) may cause pus-filled
sores to form (pyoderma).
• Many people have fevers and chills and lose their appetite and/or weight.
• Abdominal pain may develop, possibly because the liver or spleen is enlarged.
• Infants or young children may have chronic diarrhea and may not grow and develop as
expected
14. Prevention of Immunodeficiency
Disorders
• Some of the disorders that can cause secondary immunodeficiency
can be prevented and/or treated, thus helping prevent
immunodeficiency from developing. The following are examples:
• HIV infection
• Cancer
• Diabetes
15. Treatment of Immunodeficiency
Disorders
• General measures and certain vaccines to prevent infections
• Antibiotics and antivirals when needed
• Sometimes immune globulin
• Sometimes stem cell transplantation
• Treatment of immunodeficiency disorders usually involves preventing
infections, treating infections when they occur, and replacing parts of
the immune system that are missing when possible.
