ABSTRACT
BACKGROUND: Horse antithymocyte globulin (ATG) is a useful treatment for aplastic anemia and for bone marrow transplantation from HLA-mismatched donors. Mortality due to anaphylactic reaction to horse ATG has been reported. We evaluated the clinical significance of skin test and specific IgE measurement for the prediction of immediate type hypersensitivity reaction to horse ATG. SUBJECTS AND METHODS: The study subjects consisted of 25 patients who received horse ATG. Underlying diseases of the 25 patients included aplastic anemia (n=20), leukemia (n=3), lymphoma (n=1), and Gaucher's disease (n=1). Skin prick test was done on these patients using undiluted ATG solution (Upjohn, USA) with duplication. Specific IgE to ATG was detected by enzyme-linked immunosorbent assay and immunoblot analysis. RESULTS: Skin prick test was positive in 7 (28%) of 25 patients. None of the patients showing negative skin prick test experienced immediate type hypersensitivity reaction to ATG. All patients showing positive skin prick test received desensitization before the administration of a full dose of ATG. However, 3 of 7 patients showing positive skin prick test experienced immediate type hypersensitivity reaction; one of them died of anaphylaxis. Specific IgE measurement using enzyme-linked immunosorbent assay was not useful in predicting immediate type hypersensitivity reaction to ATG because of nonspecific bindings. Specific IgE measurement using immunoblot analysis was only positive in the one patient who died of anaphylaxis. CONCLUSION: Skin prick test was clinically useful in the prediction of immediate type hypersensitivity reaction to horse ATG, but specific IgE measurement was not. Further studies might be needed to develop an in vitro test for the prediction of immediate type hypersensitivity reaction to horse ATG.