Human Leukocyte Migration Inhibition as an Indicator of Cellular Hypersensitivity to Soluble Antigens

We evaluated delayed hypersensitivity in humans to three soluble an < tigens (tuberculoprotein, coccidioidin, and Candida extract) with the leukocyte migration inhibition test. Skin reactivity and migration inhibition correlated to a high degree with all the antigens. Cell migration was not inhibited in subjects without a positive skin test or clinical history. Sensitivity to tuberculin measured in vitro after vaccination with Bacillus of Calmette and Guerin correlated well with 25 tuberculin PPD skin test units, and indicates that the LMI test is more sensitive in detecting cellular hypersensitivity than skin tests with intermediate strength tuberculin PPD.