Background: Breast milk is thought to contain its own complex immune system. Whether or not this is altered in allergic individuals is not yet known.
Methods: By ELISA techniques, inflammatory markers (MIP-1alpha, sICAM-1) and T(H)1 (interferon-gamma [IFN-gamma]), as well as T(H)2 cytokines (interleukin [IL]-4, IL-10), were investigated in serum and milk samples from nonallergic (n = 23) lactating women and those with respiratory allergies (n = 19) during the first week postpartum.
Results: IFN-gamma was not detected in either serum or milk. IL-10 was more often found to be above the detection limit in both milk and serum samples from allergic mothers. IL-4 was detected in almost all serum samples with a wide variation. In milk, IL-4 was found in about 20% of the samples. MIP-1alpha was not detected in the serum but was detected in the milk of 23% of the nonatopic and 53% of the allergic mothers. Soluble ICAM-1 was present in all samples. Surprisingly, serum levels of sICAM-1 in allergic mothers (271+/-97 ng/ml) were significantly lower (P<0.001) than in nonatopic subjects (375+/-86 ng/ml). Concentrations of sICAM-1 in milk were similar in both groups.
Conclusions: The concentrations of proinflammatory markers and cytokines in breast milk did not differ significantly between allergic and nonatopic mothers. In some individuals, high levels of MIP-1alpha, IL-10, and sICAM-1 could be found. However, the significance of these components for the breastfed infant is still unclear.