Peripheral blood T lymphocyte subsets in children with congenital asplenia.

The aim of the current study was to examine whether a congenital lack of the spleen changes distribution, state of activation and function of peripheral lymphocyte T subsets. Seven children with congenital asplenia (CA) aged 1.5-17 years and seven age-matched controls were tested. By triple-color flow cytometry we examined: (1) the expression of CD3(+), CD4(+), CD8(+), CD19(+), and CD56(+) on lymphocytes; (2) the distribution of CD45RA(+) and CD45RO(+) in CD4(+) and CD8(+); (3) the expression of CD27(+) in the CD4(+) and CD8(+) T-cell-bearing CD45RA(+), CD45RO(+), or CD45RB(+). Lymphocyte proliferative responses and cytokines production (IFN-gamma, IL-6, TNF-alfa, and IL-10) in anti-CD3-induced peripheral blood mononuclear cells were tested. The results indicate (1) a normal distribution of the basic lymphocyte subsets, (2) low CD3(+)/CD8(+) percentage but expressing CD8(+high) and non-significantly elevated CD4(+)/CD8(+) ratio, (3) CD45RA(+high) and CD27(+high) in the CD4(+) and CD8(+) T cell, and (4) CD45RB(+high) in the CD4(+) and CD45RO(+high) in the CD8(+). The distribution of CD27(+) in the CD45RA(+) and CD45RO(+) CD4(+) T cells remained unchanged. However, the percentage of CD8(+)/CD45RO(+)/CD27(+) T cells tended to be elevated. Altogether, these data indicate that CA is connected with (1) the presence CD4(+) T cells expressing the "naive" phenotype (CD45RA(+high) RB(+high) and CD27(+high)), (2) high numbers of activated CD8(+) T cells shifted toward the memory phenotype (CD45RO(+high)) but still showing high CD27(+) expression, which may indicate failure in T CD8(+) cytotoxic effectors differentiation, and (3) a tendency to the rather pro-inflammatory status of cells, low IL-10 expression, and suboptimal lymphocytes responses to mitogenic stimulation.