Red blood cells make up about 40 percent of the blood. The body must have red blood cells to supply oxygen to the tissues of the body; these are produced by the bone marrow. Anemia is when the body does not have enough healthy red blood cells. The white blood cells produce antibodies, which attach themselves to red blood cells and are transported to sequester germs and other foreign substances that should not be there. In some people, however, antibodies are attached to red blood cells but are not recognized by the body, but are targeted as extraneous and destroyed substances. In the process of destruction of antibodies, even the red blood cells are destroyed, causing autoimmune hemolytic anemia (ANEI). There are two main types of ANEI. The exact cause of the primary form is not known. With secondary ANEI, the cause can be attributed to another disease such as: lymphomas, rheumatoid arthritis, ulcerative colitis, lupus erythematosus, chronic renal failure, thyroid disease and some immunodeficiency syndromes. The condition can also be determined by respiratory virus infections; in this case the antibodies and the anemia disappear once the infections are resolved. It is also possible that people acquire antibodies from their mother at birth, but this is often only temporary.
Symptoms and diagnosis
The symptoms of autoimmune hemolytic anemia can vary from person to person, but there are some common symptoms of the disease: pallor, fatigue, tachycardia, shortness of breath, muscle pain, diarrhea and appearance of dark urine (dark yellow or brownish). This is due to the metabolism of hemoglobin in pigments that give this typical color to the urine. There are several tests and tests on blood and urine used to diagnose ANEI; many of these tests are often used together or with additional tests.
Direct Coombs Test: This test looks for antibodies that are attached to the patient’s red blood cells and could cause their premature death.
Indirect Coombs Test: This form of the Coombs test looks for any free antibodies in the body that are against certain red blood cells.
Hemoglobin in the urine: this blood test measures the amount of hemoglobin present in the blood. Less than normal ranges may be due to anemia.
Hemochromocytometric test: this blood test determines how many red blood cells are present in the body. A low level of red blood cells can signal anemia.
Serum hemoglobin: it is a blood test that is used to determine the level of free hemoglobin in the liquid part of the blood. Free hemoglobin is the term used to describe hemoglobin outside the red blood cells.
Reticulocyte count: this test measures the amount of reticulocytes, which are slightly immature red blood cells. It is done to determine if red blood cells are created at the appropriate production rate. The interval will be higher if the body has low hemoglobin levels due to bleeding or destruction of red blood cells and may be a sign of anemia.
Serum bilirubin. Bilirubin is a pigment that is found in bile, which is produced by the liver. A blood test can measure the amount of bilirubin in the blood. High levels can be a direct sign of damage or liver disease.
Serum aptoglobin. Haptoglobin is a protein produced by the liver. The amount of haptoglobin present in the blood shows the rate of destruction of the red blood cells.
Test of cold agglutinins. Agglutinins are antibodies that cause red blood cells to form. Cold agglutinins are active at low temperatures and warm agglutinins are active at normal body temperatures. Determining if there are hot or cold agglutinins can sometimes help explain why the disorder is occurring. Hot agglutinins can occur with some infections and reactions to drugs including penicillin. Cold agglutinins can occur with infections such as Mycoplasma pneumonia.
Therapies for ANEI
Treatment for AIHA may vary based on a number of reasons, including: age, health and general patient history; the cause and severity of the disease; and patient tolerance for specific treatments. Treating the underlying cause of AIHA can help treat AIHA. This includes the treatment of underlying diseases (infections, tumors, cancer, sensitivity to drugs). Steroids can be used to weaken the immune response, which can help improve common AIHA types. This is generally the first type of treatment for those suffering from primary AIHA. If these drugs are not effective, other immunosuppressant drugs may be used. This pharmacological treatment helps to lower the body’s immune response, helping to prevent the immune system from attacking the bone marrow. This allows the stem cells of the cord to grow, increasing the number of red blood cells. If the drugs are not effective, surgery can be used. The spleen is responsible for the removal of abnormal red blood cells from the bloodstream, including those with attached antibodies. By removing the spleen, red blood cells can be preserved, helping to prevent anemia. If the ANEI can not be treated, a blood transfusion may be necessary.
Age and autoimmune hemolytic anemia
Adults often have long-term ANEIs with anemia that frequently returns. In children, anemia is generally temporary and short-lived. ANEI is very rare in children and usually occurs after a viral disease; generally occurs during the first year of life or during adolescence. The highest rates are seen in preschoolers. Depending on what has triggered the production of antibodies, ANEI can be resolved in a few months or last for years. Long-term ANEI is more commonly found in adolescents and children under 2 years. This group is more likely to have relapses and is generally related to a secondary cause that should be investigated. Children have the same treatment options as adults but often need blood transfusions. This helps to correct severe anemia and prevents complications. But the transfusion does not correct the underlying cause, so further treatment is required. The daily routine and activities of children with ANEI are disturbed: they might be often tired, irritable, angry or scared. Parents must ensure that they follow a well-balanced diet, adequate hydration and have plenty of rest.
Some types of ANEI can not be prevented. Physicians pay special attention to potential side effects in patients with viral infections or specific drug therapies. Severe anemia can worsen heart disease or underlying lung diseases. Those who are suffering from ANEI can discuss with their doctor to help them reduce the risks and the possibility of infections. People with ANEI are often sensitive to cold, which can trigger the rupture of red blood cells. Suggestions to reduce risks include: avoiding sudden exposure to cold, taking care to keep the house warm and wear warmer clothes; avoid people with overt infections and run the annual flu vaccination.
- edited by Dr. Gianfrancesco Cormaci, PhD specialist in Clinical Biochemistry.