Expression of naive/memory (CD45RA/CD45RO) markers by peripheral blood CD4+ and CD8 + T cells in children with asthma.

Background: The role of CD4+ T cells in the immunopathogenesis of asthma is well documented. Little is known about the role of CD8+ T cells. The aim of this study was to assess peripheral blood subsets of CD4+ and CD8+ T cells expressing naive/memory markers (CD45RA+/RO+) and the activation marker (CD25+) in children with allergic asthma.

Methods: Peripheral blood mononuclear cells were isolated from children with allergic asthma and healthy children. T cell subsets were analyzed by flow cytometry for the expressions of CD45RA, CD45RO, and CD25. In this study, some differences in the memory compartment of peripheral blood T cells between asthmatic children and healthy controls were detected.

Results: The absolute number of CD8+ T cells expressing CD45RO was significantly elevated and the percentages of CD3+ T cells expressing activation marker CD25 and of CD4+ T cells expressing memory marker CD45RO were significantly lower in children with asthma compared with controls. No correlation was found between severity of asthma and peripheral blood lymphocyte subsets.

Conclusions: There were some differences in the memory compartment of peripheral blood T cells between asthmatic children and healthy controls. The increase in the number of CD8+ T cells expressing the memory marker (CD45RO) in children with allergic asthma may indicate that CD8+ T cells play a role in the pathogenesis of asthma.