Expression of the T-cell markers CB3, CB4 and CD8 in healthy and atopic children during the first 18 months of life

Background: There is little information available about the development of T-cell immunity in healthy and atopic children. We have studied prospective ly the mean fluorescence intensity of the T-cell receptor complex-associate d CD3, CD4 and CD8 in relation to atopic family history (AFH) and the devel opment of atopic disease. Methods: Children with a defined AFH (n = 172) we re followed from birth to 18 months and the cumulative history of atopic di sease was recorded. Blood samples were obtained at birth and at 18 months, and in a subgroup of 78 children also at 3, 6 and 12 months. Multicolour fl ow cytometry was used to analyse pan T-cells (CD3+CD45+CD14-), T-helper-(CD 3+CD4+) and T-cytotoxic-(CD3+CD8+) cells. Results: At 18 months, 31 childre n were atopic and 118 non-atopic. Children who developed atopic disease had a higher CD4 expression (mean fluorescence intensity, MFI) on CD4+CD3+ lym phocytes at birth and at 3 months, particularly as compared with non-atopic children without AFH. Furthermore, the CD3 expression on CD3+CD45+CD14- ly mphocytes increased more slowly with age in children with double atopic her edity, as compared with children with no or only one atopic family member. Conclusions: The higher expression of the CD4 receptor in early infancy in children who developed atopic disease compared with non-atopics suggests a delayed expression in T-helper cells. Children with a strong AFH had a slow er increase in the expression of CD3, indicating a delayed T-cell maturatio n.