Background: The precise role of leucocytes in human milk is still unresolved.
Objective: To assist in clarifying the immune mechanisms involved in the development of CMA in suckling infants, we studied the role of immunoregulatory leucocytes and their mediators in human breast milk.
Methods: The study population consisted of 43 lactating mothers and their infants, aged 0.25-8.0 months, followed-up prospectively from birth. Of these mothers, 27 had an infant with challenge-proven cow's milk allergy manifested with either skin (n = 23), gastrointestinal (n = 2) or skin and gastrointestinal symptoms (n = 3). Sixteen mothers with a healthy infant served as controls. We evaluated the spontaneous and mitogen-induced tumour necrosis factor-alpha (TNFalpha) and interferon-gamma (IFNgamma) production of human milk leucocytes and isolated peripheral blood lymphocytes in vitro with a commercial ELISA kit.
Results: TNFalpha production of breast milk leucocytes was significantly lower in the mothers with a cow's milk-allergic infant, whereas IFNgamma production of these cells was comparable in the two groups.
Conclusion: Our results suggest that in the breast milk of mothers having an infant with cow's milk allergy, the number and function of TNFalpha-producing cells is defective. This might lead to a disturbance in the development of oral tolerance and thereby to the development of CMA in suckling infants. These novel results may help in clarifying the etiopathogenesis of CMA.