[Lymphocyte phenotyping in the cord blood of newborn infants]

Ontogeny and development of phenotypically defined T-cell subsets in humans, are the source of controversy. Cord blood represents a relevant model for the study of the normal T-cell differentiation pathway. We identified T lymphocytes subsets with monoclonal antibodies (Mab) in human cord blood and adults controls in an indirect immunofluorescence assay and B lymphocytes in a direct immunofluorescence assay. No difference was noted between the two populations with followed Mab: CD3-CD4-CD8-HLA class II-IL2 receptor, with a normal ratio CD4-CD8. The percentage of CD2+ cells was lower in neonatal blood. Double labeling studies characterized a lymphocyte population CD4-CD8 positive. This study revealed absence of immature T cells with CD1 monoclonal antibodies.