Antithymocyte globulins are the preferred treatment for patients with aplastic anemia and in prevention and treatment of renal, cardiac, kidney, and bone marrow graft rejection. Several commercial preparations from different animal serums exist (horse, rabbit, murine).
Anaphylaxis < 1% of treatments.
Allergy to horses, rabbits, or murine species.
Cutaneous eruptions, periorbital edema.
Skin tests must be performed before use of antithymocyte globulins in order to detect at-risk patients.
Intradermal skin tests give false positive results.
Skin prick-tests with dilutions to 1/1000 to pure have a better predictive value.
IgE-mediated hypersensitivity (immediate reactions).
Circulating immune complexes (serum sickness).
Skin prick-tests must be performed in all patients treated with heterologous antisera.
For patients with positive skin prick-tests:
- use a preparation from other mammalian origin (horse <—> rabbit).
- Desensitization may be performed:
0.02 ml intradermal 5 µg/ml, 50 µg/ml, 500 µg/ml, 5 000 µg/ml at ten minutes intervals then
0.5 ml subcutaneous 50 µg/ml, 100 µg/ml, 300 µg/ml, 1 000 µg/ml,
3 000 µg/ml,
5 000 µg/ml at ten minutes intervals then
0.5 mg/min, 1 mg/min, 2 mg/min intravenous for ten minutes each with the therapeutic dose of ATG at 15 mg/kg constantly infused over 24 hours.