Objective: To examine innate IL-10 production in response to microbial stimuli and intestinal Bifidobacterium colonization in association with the development of infantile eczema.
Methods: We measured released levels of IL-10 from 68 cord blood mononuclear cells (CBMCs) samples by 24 hour stimulation with standard strains of Bifidobacterium (B. bifidum and B. adolescentis), Lactobacillus rhamnosus GG (LGG), peptidoglycan (PGN) by ELISA. Toll like receptor (TLR) 2 expression on CD14 positive CBMC was analyzed by flow cytometry. Fecal Bifidobacterium at 4 days and 1 month of age were assessed by real-time PCR. The neonates were followed at 1, 4, and 7 month to determine development of infantile eczema.
Results: Frequency and count of Bifidobacterium at 4 days and 1 month were not different between infants with eczema (n = 16) and non-eczema (n = 52). Released levels of IL-10 from CBMCs were significantly lower by B. bifidum, B. adolescentis, LGG and PGN in eczema than in non-eczema. TLR2 expression on CD14 positive cells of CBMCs was not different between the two groups. In 40 infants colonized with Bifidobacterium at 4 days, the incidence of eczema was 45% in 20 infants in whom IL-10 was not detected by stimulation with PGN, whereas it was 5% in 20 infants in whom IL-10 was detected (P = 0.0084). Similar results were observed with all bacterial stimuli.
Conclusions: These results suggest that an impaired regulatory innate immune response to beneficial bacteria is associated with the development of infantile eczema, even in the presence of intestinal commensals.