T cell receptor Vβ repertoire of T lymphocytes and T regulatory cells by flow cytometric analysis in healthy children

Evaluation of the T cell receptor (TCR) V beta repertoire by flow cytometric analysis has been used for studying the T cell compartments for diseases in which T cells are implicated in the pathogenesis. For the interpretation of these studies information is needed about V beta usage in healthy individuals and there are few data for normal usage in paediatric populations. We examined the T lymphocyte (sub)populations in 47 healthy controls (age range: 3 months-16 years). We found non-random V beta usage with skewed reactivity of some families towards CD4(+) or CD4(-) T cells. Importantly, there appeared to be no significant change in V beta usage according to age group. Some controls showed expansions in some V beta families, although incidence of such expansions was low. We went on to examine the repertoire of CD4(+)CD25(Bright) T regulatory cells in 25 healthy controls. We found overlapping quantitative usage for each of the V beta families between CD4(+)CD25(-) and CD4(+)CD25(Bright) T cells. However, there was a significant preferential usage for five V beta families and decreased usage of two V beta families in the CD4(+)CD25(Bright) T cells, suggesting that although they overlap there may be subtle but important differences in the TCR repertoire of T regulatory cells.