Cow's milk challenge through human milk evokes immune responses in infantswith cow's milk allergy

Objectives: In order to measure the immune response evoked in breast-fed in fants with cow's milk allergy (CMA) by cow's milk challenge through human m ilk, mothers were given increasing doses of cow's milk after they had been on a cow's milk elimination diet. Another objective was to study the secret ion of beta-lactoglobulin (BLG) into human milk before and during milk chal lenge in relation to the appearance of symptoms in infants. Study design: Seventeen asymptomatic mothers who had infants with challenge -proven CMA and 10 asymptomatic mothers who had healthy infants were recrui ted. Infants ranged in age from 1.8 to 9.4 months. A solid-phase enzyme-lin ked immunoassay (ELISPOT) was used to assess the total number of immunoglob ulin-secreting and specific antibody-secreting cells. Flow cytometry was us ed to enumerate different lymphocyte subpopulations among peripheral blood lymphocytes primed during provocation by cow's milk antigens. BLG levels we re assessed in human milk before the challenge and 1, 2, 3, and 4 hours aft er the commencement of the challenge. Results: All but one of the infants with CMA showed symptoms of CMA during cow's milli. challenge through human milk. There was a significant rise in the total number of immunoglobulin-secreting cells in the IgA and IgG class es associated with a positive cow's milli: challenge response; but the prop ortions of peripheral blood B cells bearing CD19, CD23, CD19 and 23, CD5, o r CD19 and CD5 were comparable. BLG levels were comparable in both study gr oups. Conclusions: Most of the infants with CMA reacted to cow's milk challenge t hrough human milk. Hypersensitivity reactions to food antigens through huma n milk may be more common than previously thought.