Lymphocyte Immune Globulin

Lymphocyte immune globulin

Definition

Lymphocyte immune globulin is a drug used to suppress the immune system. Lymphocyte immune globulin is also known by the generic name anti-thymocyte globulin (ATG) and the brand names Atgam and Thymoglobulin. Atgam first received FDA approval in 1981 and Thymoglobulin in 1999. As of 2001, no generic preparations are available.

Purpose

Lymphocyte immune globulin is used to treat aplastic anemia and to prevent rejections during bone marrow transplantation . This drug has also been used experimentally to treat advanced non-Hodgkin's lymphomas and cutaneous T-cell lymphoma .

Description

This drug suppresses the immune system by slowing down T cells, cells critical in immunity. Without them, the immune system is essentially paralyzed. Lymphocyte immune globulin contains antibodies that attach to T cells and prevent them from working properly. This drug also decreases the number of T cells in the blood.

Lymphocyte immune globulin is made by vaccinating an animal with immature human T cells, then collecting the antibodies made against them. Atgam is made in horses and Thymoglobulin in rabbits.

Atgam is labeled for use only in kidney transplantation and aplastic anemia, and Thymoglobulin is specifically approved only for kidney transplantation. The effectiveness of either drug for treating aplastic anemia in cancer patients, however, is unknown.

Lymphocyte immune globulin is often used off-label to treat graft-versus-host disease (GVHD) after bone marrow transplantation. The drug has been beneficial for GVHD patients in some studies, but its effectiveness has not been conclusively demonstrated. In some clinical trials , it is also being used to prepare the patient's body for bone marrow transplantation. This drug produces short partial remissions of some lymphomas in published experiments.

Recommended dosage

The usual dose of Atgam in adults is 10-30 mg/kg (1 kilogram is 2.2 pounds). Doses of 5-25 mg/kg have been given to a few children. Thymoglobulin, which is about 10 times stronger, has a recommended dose of 1-1.5 mg/kg in adults. Typically these drugs are given daily or every other day for several days or weeks. They are injected into the blood over several hours, under close supervision in the hospital or clinic.

Precautions

Patients should not take Atgam if they are allergic to horse proteins or Thymoglobulin if they are allergic to rabbit proteins. Patients should tell their doctor about any current or previous blood cell problems and about all their prescription and over-the-counter drugs.

Lymphocyte immune globulin can make infections more serious. Patients should check with their doctor if they have any symptoms of an infection, such as chills, fever , or sore throat. They should also avoid people with contagious diseases and anyone recently vaccinated with an oral polio vaccine. The drug decreases the effectiveness of vaccinations given just before or during treatment. Some types of vaccines are not safe to receive while taking this drug.

Lymphocyte immune globulin does not interact with any specific foods. However, patients should check with their doctor for specific recommendations for eating and drinking before the treatment.

Patients should be careful in planning their activities, as this drug can cause dizziness.

Side effects

Thymoglobulin and Atgam have very similar side effects. However, Thymoglobulin is approximately twice as likely to decrease the number of white blood cells and three times as likely to result in malaise. Dizziness is much more common with Atgam. Other numerous side effects caused by both drugs include:

• Chills or fever in most patients
• Risk of developing an infection, which has been seen in up to 30% of patients, and sepsis in approximately 10%
• Risk of bleeding, due to thrombocytopenia (seen in 30-45% of patients)
• Rarely, anemia or the destruction of white blood cells other than T cells
• Pain, swelling, and redness where the drug is injected (minimized by injecting the drug into the faster-moving blood in a large vein)
• Allergic reactions (Serious allergic reactions can cause difficulty breathing, swelling of the tongue, a drop in blood pressure, or pain in the chest, sides, or back. Severe allergic reactions are potentially life-threatening, but rare; milder allergic reactions can result in itching , hives, or rash. Skin tests are often done to predict the likelihood of an allergic reaction, but are not foolproof.)
• Serum sickness, an immune reaction against the drug (Can result in fever, chills, muscle and joint aches, rash, blurred vision, swollen lymph nodes, or kidney problems; serum sickness is common when lymphocyte immune globulin is used alone for aplastic anemia, but fairly rare when it is combined with other drugs that suppress immunity.)
• Headaches, pain in the abdomen, diarrhea , nausea or vomiting, fluid retention, weakness, rapid heartbeats, or an abnormal increase in blood potassium (these side effects develop in more than a fifth of all patients during treatment)
• Uncommon side effects such as kidney damage, high blood pressure, heart failure, lethargy, abnormal sensations such as prickling in the skin, seizures, pulmonary edema, and adult respiratory distress syndrome
• Risk of developing lymphoma or leukemia, if the immune system is greatly suppressed for a long time

Side effects in pregnant or nursing women

The effects of this drug on an unborn child are unknown. Doctors are not sure if this drug reaches breast milk.

Methods of preventing or reducing side effects

Drugs such as antihistamines, acetaminophen, and corticosteroids can prevent or decrease some side effects, including fevers, chills, and allergic reactions. Antibiotics may help to prevent infections.

Interactions

Combining this drug with other medications that suppress the immune system (including chemotherapy ) can severely suppress immunity. Drugs that slow blood clotting, such as aspirin, can increase the risk of bleeding. Any drug that reduces the symptoms of an infection, including aspirin and acetaminophen, can increase the risk that a serious infection will go undetected.

See Also Myelosuppression; Immune response; Infection and sepsis; Neuropathy

Anna Rovid Spickler, D.V.M., Ph.D.

KEY TERMS

Adult respiratory distress syndrome (ARDS)

—A lung disease characterized by widespread lung abnormalities, fluid in the lungs, shortness of breath, and low oxygen levels in the blood.

Antibodies

—Proteins made by the immune system that attach to targeted molecules and cells.

Aplastic anemia

—Failure of the bone marrow to make enough blood cells.

Blood cells

—Cells found in the blood, including red blood cells that carry oxygen, white blood cells that fight infections, and platelets that help the blood to clot.

Bone marrow

—A group of cells and molecules found in the centers of some bones. It makes all of the cells found in the blood, including the cells involved in immunity.

Graft-versus-host disease (GVHD)

—A disease that develops when immune cells in transplanted bone marrow attack the body.

Immune system

—The cells and organs that defend the body against infections.

Pulmonary edema

—A disease characterized by excessive fluid in the lungs and difficulty breathing.

Sepsis

—An infection that has spread into the blood.

Serum sickness

—A type of allergic reaction against blood proteins. Serum sickness develops when the immune system makes antibodies against proteins that are not normally found in the body.

Skin test

—A test used to diagnose allergies.

T lymphocyte or T cell

—A type of white blood cell. Helper T cells aid other cells of the immune system, while cytotoxic T cells destroy abnormal body cells, including those that have been infected by a virus.

Thrombocytopenia

—Too few platelets in the blood.