Evidence for T-cell involvement during the acute phase of echovirus meningitis.

Little is known about the cellular immune response during the acute phase of enterovirus infection. This was studied in patients with echovirus meningitis by analysing changes in the lymphocyte subset distribution both in blood and in cerebrospinal fluid (CSF) and their stage of activation. A significant increase of whole T-cell and CD4+ T-cell counts was observed in CSF in parallel with a slight decrease of T-cell percentage in blood. Activation of the cellular immune response is supported by the observation of elevated neopterin levels in serum and CSF. However, the phenotypic markers of T-cell activation, IL-2 receptor (CD25), and HLA-DR antigens were not detected in blood or in CSF.