Leukocyte migration inhibition factor test as a diagnostic tool for cow's milk allergy

Peripheral blood lymphocytes of children suspected of having cow's milk allergy (CMA) were incubated with cow's milk proteins (β-lactoglobulin, α-lactalbumin and casein) to study release of lymphokines as a result of a specific cell-mediated immunity response to these allergens. LIF (leukocyte migration inhibition factor) production was evaluated by measuring migration areas of leukocytes of healthy donors packed in capillary tubes and added by the the supernatant of whole blood cultures, with and without allergens. Of 57 children studied, 10 were normal controls, 12 had chronic diarrhea, 16 were suspected of CMA not confirmed by milk challenge, 19 had CMA confirmed by one of two milk challenges. LIF Test was positive in 68% of patients with CMA and in 8% of other children. The LIF results are more correlated with the diagnosis than other tests commonly employed. Five patients with CMA reexamined when able to tolerate milk had a decreased production of lymphokines. This study emphasizes the role of cellmediated immunity reactions in the pathogenesis of cow's milk allergy. LIF TEst is proposed as a valid and specific aid for the diagnosis of CMA and as a useful tool in documenting the loss of hypersensitivity.