Differences in protein fraction from goat and cow milk and their role on cytokine production in children with cow's milk protein allergy

Garganica goat milk was characterized for protein composition and the impact of milk protein mixture, casein and β-lactoglobulin fraction on cytokine production by cultured peripheral blood mononuclear cells from infants with cow's milk protein allergy. Bulk milk samples were collected in a dairy goat farm located in the Gargano area (Southern Italy), cow milk was used as control. Ten patients with cow's milk protein allergy (6 males; mean age 8.4 ± 6.4 months) and ten non-allergic control subjects (6 males; mean age 7.4 ± 3.1 months) were consecutively included in the study. Although the amount of total casein was comparable in cow and goat milk (56.08% vs. 55.33%, respectively) the distribution of principal casein fractions was different according to species. α-CN on total casein was more than 50% both in raw and pasteurized cow milk whereas it was always lower than 40% in goat milk and an opposite trend was observed for β-CN. Production of tumor necrosis factor-α after exposure to goat milk casein and β-lactoglobulin was lower than after exposure to the same fractions from cow milk. Goat milk induced higher levels of regulatory interleukin-10 by peripheral blood mononuclear cells than cow milk. Results on tumor necrosis factor-α evidenced that it is important to test the immune reactivity against each protein fraction before considering goat milk as a safe substitute for feeding infant with cow's milk protein allergy.