• A direct assay using the mixed leukocyte migration inhibition technique for leukocyte inhibition factor (LIF) production has shown that nickel-sensitive subjects can be distinguished from nonallergic controls. The difference between the two groups' migrating indexes was obtained with nickel sulfate in 199 medium at a concentration of 150 μg/ml and without prior coupling to a carrier protein. A concise review of the principal in vitro assays for cell-mediated immunity is included.
(Arch Dermatol 112:1741-1744, 1976)