Lymphocyte subpopulations in the neonate: high percentage of ANAE+ cells with low avidity for sheep erythrocytes.

In the present study we have stained for alfa-naphthyl acetate esterase (ANAE) cord blood lymphocytes (CBL) as well as cord blood E rosetting cells. The results obtained showed that the percentage of E rosettes (E+) is lower in cord blood than in adult peripheral blood when rosetting is carried out with untreated sheep red blood cells (SRBC), while there is no significant difference if SRBC are previously treated with 2-aminoethylisothiouronium bromide (AET). ANAE-positive cells (A+) were higher in cord than in adult blood. ANAE staining of E+ cells showed that CBL include a high percentage of A+ cells with low avidity for SRBC which could represent immature lymphocytes related to the T-cell lineage.