Some causes of acquired immunodeficiency

Hereditary and metabolic diseases

- diabetes - Down syndrome - kidney failure - malnutrition - sickle cell anemia

Chemicals and treatments that suppress the immune system

- cancer chemotherapy - corticosteroids - immunosuppressive drugs - radiation therapy

Infections

- chickenpox - cytomegalovirus infection - German measles (congenital rubella) - AIDS - infectious mononucleosis - measles - severe bacterial infection - severe fungal infection - severe tuberculosis

Blood diseases and cancer

- agranulocytosis - all cancers - aplastic anemia - histiocytosis - leukemia - lymphoma - myelofibrosis - myeloma

Surgery and trauma

- bums - removal of the spleen

Miscellaneous

- alcoholic cirrhosis - chronic hepatitis - normal aging - sacroiditis - systemic lupus erythematosus

Symptoms

Most healthy infants have 6 or more minor respiratory tract infections a year, particularly when exposed to other children. In contrast, infants with impaired immunity usually develop severe bacterial infections that persist, recur, or lead to complications. For example, sinus infections, chronic ear infections, and chronic bronchitis commonly follow sore throats and head colds in these infants. The bronchitis may progress to pneumonia.

The skin and mucous membranes lining the mouth, eyes, and genitals are susceptible to infection. Thrust, a fungal infection of the mouth, along with mouth sores (ulcers) and inflammation of the gums, may be an early sign of impaired immunity, inflammation of the eyes (conjunctivitis), hair loss, severe eczema, and areas of enlarged, broken capillaries under the skin are also signs of a possible immunodeficiency disorder. Infections in the gastrointestinal tract may lead to diarrhea, extreme gassiness, and weight loss.

Signs of chronic infection

- pale, thin appearance	- skin rash
- pustules	- eczema
- broken blood vessels	- hair loss
- purple biotches	- redness of the lining of the eye (conjunctivitis)
- enlarged lymph nodes, such as those in the neck, armpits, and groin	- scarred and perforated eardrums
- crusted nostrils (from discharge)	- enlarged liver and spleen
- in infants, redness around the anus from chronic diarrhea

Diagnosis

At first, a hereditary problem with the immune system may be difficult to diagnose. When severe or rare infections occur repeatedly, in either young children or adults, a doctor suspects an immunodeficiency disorder. Since immunodeficiency disorders in very young children are often hereditary, the presence of recurring infections in other children in the family is an important clue. Infections with common organisms that normally don’t make people sick, such as Pneumocystis or cytomegalovirus, suggest a problem with the immune system.

In older children and adults, the doctor reviews the medical history to determine if a drug, an exposure to a toxic substance, a previous surgery (such as a tonsillectomy or adenoidectomy) or another medical condition might be the cause. A sexual history is also important, since human immunodeficiency virus (HIV) infection, a common cause of immune dysfunction in adults, is often acquired through sexual contact. Newborns can be infected with HIV if their mothers are infected; older children can be infected through sexual abuse.

The type of infection gives the doctor clues to the type of immunodeficiency. For example when infections are caused by certain bacteria such as Streptococcus, the problem is likely to be that the B-lymphocytes don’t produce enough antibodies. Severe infections from viruses, fungi and unusual organisms such as Pneumocystis usually result from T-lymphocytes problems. Infections with the bacteria Staphylococcus and Escherichia coli usually indicate that phagocytic white blood cells (cells that kill and ingest invading microorganisms) aren’t moving properly or aren’t effectively killing the invaders. Infections with the bacterium Neisseria art often a sign of problems in the complement system, proteins in the blood that help rid the body of infection.

The age at which problems begin is also important. Infections in infants under 6 months of age usually indicate T-lymphocyte abnormalities; infections in older children usually indicate problems with antibody production and B-lymphocytes. Immunodeficiency that begins in adulthood is rarely hereditary; a much more likely cause is AIDS or other conditions such as diabetes, malnutrition, kidney failure and cancer.

Defining the exact nature of the immunodeficiency disorder requires laboratory testing, usually of the blood. First, a doctor determines the total number of white blood cells and the number of specific types of white blood cells. The white blood cells are examined under a microscope for abnormalities in appearance. Antibody (immunoglobulin) levels are checked, as are the numbers of red blood cells and platelets. The levels of complement can also be measured.

If any test results are abnormal, additional tests are generally needed. For example, if the number of lymphocytes (a type of white blood cell) is low, the doctor may measure the levels of T- and B-lymphocytes. Laboratory tests can even determine which type of T- or B-lymphocyte is affected. In AIDS, for example, the number of CD-4 T-lymphocytes is decreased in comparison to the number of CD-8 T-lymphocytes.

Another useful laboratory test helps determine whether white blood cells are functioning normally by measuring their ability to grow and divide in response to certain chemical stimuli called mitogens. Their ability to destroy foreign cells and organisms can also be tested.

The function of T-lymphocytes can be tested by using a skin test to analyze the body’s ability to react to foreign substances. In this test, small amounts of protein from common infectious organisms such as yeast are injected under the skin. Normally, the body reacts by sending T-lymphocytes to the area, causing the area to become slightly swollen, red and warm. This test isn’t used until a child is 2 years old.

Prevention and Treatment

Some of the diseases that impair the immune system later in life can be prevented or treated. For example, close control of blood sugar levels in people with diabetes helps improve the ability of white blood cells to prevent infections. Successfully treating cancer is likely to restore the function of the immune system. Safe sex practices help prevent the spread of HIV (the virus that causes AIDS). Attention to diet can prevent immune disorders that arise from malnutrition.

People who have immunodeficiency disorders should maintain excellent nutrition. Have good personal hygiene, and avoid eating undercooked food and being in contact with people who have infectious diseases. Some people must drink only bottled water. They should avoid smoking, inhaling secondhand cigarette smoke, and using illegal drugs. Fastidious dental care helps prevent infections in the mouth. Those who are able to produce antibodies are vaccinated, but only killed viral and bacterial vaccines rather than live vaccines (such as oral polio vaccine, measles-mumps-rubella vaccine, and BCG vaccine) are used in people with a B- or T-lymphocyte deficiency.

Antibiotics are given at the first sign of an infection. An infection that’s rapidly worsening requires prompt medical attention. Some people, particularly those with Wiskott-Aldrich syndrome and those without a spleen, are given preventive antibiotics as a prophylactic measure before infections occur. Trimethoprim-sulfamethoxazole is often used to prevent pneumonia.

Drugs that enhance the immune system, such as levamisole, inosiplex, and thymic hormones, haven’t been successful in treating people who have low numbers of poorly functioning white blood cells. Low antibody levels can be raised with infusions or injections of immune globulin, usually given monthly. Injections of interferon gamma are beneficial in treating chronic granulomatous disease.

Experimental procedures, such as transplantation of fetal thymic cells and fetal liver cells, have occasionally been helpful, particularly for people with the DiGeorge anomaly. In severe combined immunodeficiency disease with adenosine deaminase deficiency, enzyme replacement is sometimes possible. Gene therapy shows promise for this and a few other congenital immunodeficiency disorders in which the genetic defect has been identified.

A bone marrow transplant sometimes corrects a severe, congenital immune system defect. This procedure is generally reserved for the most severe disorders, such as severe combined immunodeficiency disease.

Most people who have abnormal white blood cells aren’t given blood transfusions unless the donated blood has first been irradiated, because white blood cells in the donated blood may attack those in the recipient’s blood, creating a serious, even fatal, illness (graft-versus-host disease).

People whose families are known to carry the genes for inherited immunodeficiencies may seek counseling to avoid children with the disorders. Agammaglobulinemia, the Wiskott-Aldrich syndrome, severe combined immunodeficiency disease, and chronic granulomatous disease are some disorders that can be diagnosed in the fetus by testing a sample of fetal blood or amniotic fluid. For many of these disorders, the parents or siblings can be tested to determine if they carry the defective gene.

Notes:

congenital immunodeficiency врожденный иммунный дефицит

hereditary наследственный

Human Immunodeficiency Virus вирус иммунодефицита человека

(HIV)

Acquired Immunodeficiency синдром приобретенного

Syndrome (AIDS) иммунодефицита

impair повреждать, ослаблять; причинять вред

prolonged продолжительный, длительный

trap задерживать, поглощать, нейтрализовать

sickle cell disease серповидно-клеточная болезнь (анемия)

susceptible восприимчивые, чувствительные

malnutrition недоедание, недостаточное питание

chickenpox ветряная оспа

German measles (rubella) краснуха

measles корь

miscellaneous смешанный

crusted nostrils (from discharge) ноздри, покрытые коркой (образующиеся из отделяемого из носа)

DiGeorge syndrome аплазия тимуса

graft-versus-host disease реакция «трансплантат против хозяина»

 

2. Allergic Reactions