The appearance of macrophage migration-inhibition factor in drug reactions.

Drug-induced adverse reactions were suspected in 2030 patients with known exposure to 243 different drugs. A modified direct macrophage migration-inhibition factor (MIF) test for the different drugs was carried out on blood samples from these patients. There was a positive MIF response toward one or more of the suspected drugs in 53.4% of the patients as compared to 4.9% of the control group; 155 of the 243 drugs elicited a positive MIF response. The percentage of positive responses for each particular drug was not related to the number of patients tested, reflecting the variability in specific immunogenicity of the different drugs. The high percentage of positive MIF reactions in relation to the clinical diagnosis suggests that this test can be a useful aid in the detection of the offending drug in cases of suspected drug-induced reactions.