ATG

ATG antithymocyte globulin.

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ATG,

abbreviation for antithymocyte globulin.

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globulin [glob´u-lin]

any of numerous proteins that are insoluble in water or highly concentrated salt solutions but soluble in moderately concentrated salt solutions. All plasma proteins except albumin and prealbumin are globulins. The plasma globulins are separated into five fractions by serum protein electrophoresis (SPE). In order of decreasing electrophoretic mobility these fractions are the alpha₁-, alpha₂-, beta₁-, and beta₂-globulins, and the gamma globulins.

The globulins include carrier proteins, which transport specific substances; acute phase reactants, which are involved in the inflammatory process; coagulation factors; complement components; and immunoglobulins. Examples are transferrin, a beta₁-globulin that transports iron, and alpha₁-antitrypsin, an acute phase reactant that inhibits serum proteases. The gamma globulin fraction is almost entirely composed of immunoglobulins.

accelerator globulin factor V, one of the coagulation factors.

antihemophilic globulin (AHG) factor VIII, one of the coagulation factors.

antilymphocyte globulin (ALG) the gamma globulin fraction of antilymphocyte serum; used as an immunosuppressant in organ transplantation. The term is sometimes used interchangeably with antithymocyte globulin.

antithymocyte globulin (ATG) the gamma globulin fraction of antiserum derived from animals (such as rabbits) that have been immunized against human thymocytes; an immunosuppressive agent that causes specific destruction of T lymphocytes, used in treatment of allograft rejection. The term is sometimes used interchangeably with antilymphocyte globulin.

bacterial polysaccharide immune globulin (BPIG) a human immune globulin derived from the blood plasma of adult human donors immunized with Haemophilus influenzae type b, pneumococcal, and meningococcal polysaccharide vaccines; used for passive immunization of infants under 18 months of age.

cytomegalovirus immune globulin a purified immunoglobulin derived from pooled adult human plasma selected for high titers of antibody against cytomegalovirus; administered intravenously for treatment and prophylaxis of cytomegalovirus disease in transplant recipients.

gamma globulin

1. see gamma globulin.

2. immune globulin.

hepatitis B immune globulin (HBIG) a specific immune globulin derived from plasma of human donors with high titers of antibodies against hepatitis B surface antigen (HBsAg); used for postexposure prophylaxis following contact with HBsAg-positive materials, also administered to infants of HBsAg-positive mothers.

hyperimmune globulin any of various immune globulin preparations especially high in antibodies against certain specific diseases.

immune globulin

1. immunoglobulin.

2. a concentrated preparation containing mostly gamma globulins, predominantly IgG, from a large pool of human donors; used for passive immunization against measles, hepatitis A, and varicella and for treatment of hypogammaglobulinemia or agammaglobulinemia in immunodeficient patients, administered intramuscularly. See also immune g. intravenous (human).

immune globulin intravenous (human) a preparation of immune globulin suitable for intravenous administration; used in the treatment of primary immunodeficiency disorders and idiopathic thrombocytopenic purpura, and as an adjunct in the treatment of Kawasaki disease and the prevention of infections associated with chronic lymphocytic leukemia, bone marrow transplantation, and pediatric human immunodeficiency virus infection.

immune human serum globulin immune globulin (def. 2).

immune serum globulin immune g. (def. 2).

pertussis immune globulin a specific immune globulin derived from the blood plasma of human donors immunized with pertussis vaccine; used for the prophylaxis and treatment of pertussis.

rabies immune globulin a specific immune globulin derived from plasma of human donors hyperimmunized with rabies vaccine; administered in conjunction with rabies vaccine in cases of bite or scratch exposure to known or suspected rabid animals.

respiratory syncytial virus immune globulin intravenous a preparation of immunoglobulin G from pooled adult human plasma selected for high titers of antibodies against respiratory syncytial virus; used for passive immunization of infants and young children.

Rh₀(D) immune globulin a specific immune globulin derived from human blood plasma containing antibody to the erythrocyte factor Rh₀(D); used to prevent Rh-sensitization of Rh-negative females and thus prevent erythroblastosis fetalis in subsequent pregnancies; administered within 72 hours after exposure to Rh-positive blood resulting from delivery of an Rh-positive child, abortion or miscarriage of an Rh-positive fetus, or transfusion of Rh-positive blood. It is also used as a platelet count stimulator in the treatment of idiopathic thrombocytopenic purpura.

serum g's all plasma proteins except albumin, which is not a globulin, and fibrinogen, which is not in the serum. The serum globulins are subdivided into alpha-, beta-, and gamma-globulins on the basis of their relative electrophoretic mobilities.

specific immune globulin a preparation of immune globulin derived from a donor pool preselected for high antibody titer against a specific antigen, such as hepatitis B immune globulin.

tetanus immune globulin a specific immune globulin derived from the blood plasma of human donors who have been immunized with tetanus toxoid; used in the prophylaxis and treatment of tetanus.

thyronine-binding globulin (TBG) (thyroxine-binding globulin) an acidic glycoprotein that is the main binding protein in the blood for thyroxine, and less firmly for triiodothyronine.

vaccinia immune globulin a specific immune globulin derived from the blood plasma of human donors who have been immunized with vaccinia virus smallpox vaccine; used as a passive immunizing agent.

varicella-zoster immune globulin (VZIG) a specific immune globulin derived from plasma of human donors with high titers of varicella-zoster antibodies; used for prevention or amelioration of varicella in immunocompromised patients exposed to the disease and in neonates whose mothers develop varicella in the perinatal period.

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lymphocyte immune globulin (antithymocyte globulin equine, ATG, ATG equine, LIG)

Atgam

Pharmacologic class: Immunoglobulin

Therapeutic class: Immunosuppressant

Pregnancy risk category C

FDA Boxed Warning

• Give drug under supervision of physician experienced in immunosuppressive therapy for treatment of renal transplant or asplastic anemia patients, in facility with adequate laboratory and supportive resources

Action

Unknown. Thought to inhibit cell-mediated immune response by altering function of or eliminating T lymphocytes in circulation.

Availability

Injection: 50 mg /ml in 5-ml ampules

⊘Indications and dosages

➣ To prevent acute renal allograft rejection

Adults: 15 mg/kg/day I.V. for 14 days, then switch to alternate-day dosing for 14 days (for a total of 21 doses in 28 days). Give first dose within 24 hours of transplantation.

➣ Acute renal allograft rejection

Adults and children: 10 to 15 mg/kg/day I.V. for 14 days, then may switch to alternate-day dosing for 14 days (for a total of 21 doses in 28 days). Start therapy at first sign of rejection.

➣ Aplastic anemia in patients ineligible for bone marrow transplantation

Adults: 10 to 20 mg/kg/day I.V. for 8 to 14 days; then may give additional alternate-day doses for a total of up to 21 doses in 28 days

Off-label uses

• Bone marrow, liver, and heart transplantation
• Multiple sclerosis
• Myasthenia gravis
• Scleroderma

Contraindications

• History of severe systemic reaction to lymphocyte immune globulin or other equine preparation

Precautions

Use cautiously in:
• severe renal or hepatic disease
• pregnant or breastfeeding patients
• children.

Administration

☞ Know that drug should be given only by health care professionals experienced in immunosuppressive therapy for treating aplastic anemia or renal transplant patients, in facilities equipped and staffed with adequate laboratory and supportive resources.
☞ Because of high risk of anaphylaxis, perform intradermal skin test before first dose. Inject 0.1-ml dose of 1:1,000 dilution of LIG intradermally; a control test using 0.9% sodium chloride injection is injected contralaterally. Observe site every 15 to 20 minutes during first hour after injection, and monitor patient for systemic manifestations. Local reaction of 10 mm or greater with wheal, erythema, or both (with or without pseudopod formation and itching or marked local swelling) indicates positive test (which warrants consideration of alternate therapy). Systemic reaction (such as tachycardia, dyspnea, hypotension, or anaphylaxis) precludes LIG therapy.
• Premedicate with antipyretic, antihistamine, or corticosteroid, as prescribed, to minimize reactions.
• For I.V. infusion, dilute prescribed dose in 250 to 1,000 ml of 0.45% or 0.9% sodium chloride injection. (Don't dilute in dextrose solutions or highly acidic solutions.) Final concentration shouldn't exceed 4 mg/ml. Infuse total daily dose over at least 4 hours.
• When adding drug to infusion container, invert container so air doesn't enter. Gently swirl or rotate container to mix solution.
• Using in-line filter with pore size of 0.2 to 1 micron, infuse into central vein, shunt, or arteriovenous fistula over at least 4 hours.
• Be aware that drug is usually given concurrently with azathioprine and corticosteroids when used for allograft rejection.

Route	Onset	Peak	Duration
I.V.	Immediate	5 days	Unknown

Adverse reactions

CNS: malaise, agitation, headache, dizziness, weakness, syncope, encephalitis, seizures

CV: hypotension, hypertension, chest pain, bradycardia, tachycardia, cardiac irregularities, phlebitis, myocarditis, thrombophlebitis, heart failure

EENT: periorbital edema

GI: nausea, vomiting, diarrhea, stomatitis

Hematologic: leukopenia, agranulocytosis, thrombocytopenia, aplastic anemia

Hepatic: hepatosplenomegaly

Metabolic: hyperglycemia

Musculoskeletal: joint pain or stiffness, myalgia, back pain

Respiratory: dyspnea, pleural effusion

Skin: rash, pruritus, urticaria, diaphoresis, night sweats

Other: burning soles and palms, fever, chills, pain at infusion site, edema, lymphadenopathy, hypersensitivity reactions including serum sickness and anaphylaxis

Interactions

Drug-diagnostic tests. Creatinine, glucose, hepatic enzymes: increased values

Hemoglobin, platelets, white blood cells: decreased values

Kidney and liver function tests: abnormal results

Patient monitoring

☞ During infusion, watch for signs and symptoms of hypersensitivity reaction, such as rash, respiratory distress, or chest, flank, or back pain. Be aware that this reaction may occur even with a negative skin test.
☞ Discontinue drug if renal transplant patient develops signs or symptoms of anaphylaxis or severe thrombocytopenia or leukopenia.
• Be aware that product derives from equine and human blood components and may transmit infections.
• Monitor for signs and symptoms of infection, such as fever, malaise, and sore throat (caused by immunosuppression).

Patient teaching

☞ Tell patient to immediately report adverse reactions during infusion (such as pain at infusion site) as well as systemic complaints (such as easy bruising or bleeding or signs of hypersensitivity reaction).
• Instruct patient to avoid sources of infection, such as people with known infections. Tell him to promptly report signs or symptoms of infection.
☞ Advise patient to immediately report evidence of serum sickness, including fever, joint pain, nausea, vomiting, lymphadenopathy, and rash.
☞ Caution female patient not to take drug if she is pregnant.
• Tell female patient to inform prescriber if she is breastfeeding.
• As appropriate, review all other significant and life-threatening adverse reactions and interactions, especially those related to the tests mentioned above.

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ATG

1 Angiotensinogen 2 Antithymocyte globulin, see there 3. Antithyroglobulin–antibodies