[Serum soluble CD2, CD4 and CD8 levels in infectious mononucleosis]

Acute infectious mononucleosis (IM) is a lymphoproliferative disease caused by the Epstein-Barr virus (EBV) infection. It has been reported that soluble T cell antigens are released from cells in response to T cell activation. In the present study, we investigated whether soluble antigen levels of CD2, CD4 and CD8 in serum increase during acute IM. Soluble CD2, CD4 and CD8 levels in serum were measured by a sandwich enzyme immunoassay. In addition, peripheral blood T cell subsets were analyzed by single and two color flow-cytometric analyses in IM. Patients with IM had increased levels of soluble CD2, CD4 and CD8 in serum samples obtained during acute stages. We found a positive correlation between serum levels of soluble CD8 and absolute counts of HLA-DR+CD8+T cells during acute IM. In addition, the correlation between soluble CD8 levels and serum GOT or GPT levels was shown to be positive during acute IM. Our findings suggest that the soluble antigen levels of CD2, CD4 and CD8, in particular CD8, in serum are an important immunologic parameter for determining the activation of T cells during acute IM.