Changes in the level of soluble CD-2 molecules in the serum of HIV-infected individuals.

It has been shown previously that the level of soluble CD-2 determinants (E-receptors) is elevated in the serum of patients with various immunodeficiency states. The aim of the present preliminary study was to determine the level of soluble CD-2 in the sera of individuals infected with human immunodeficiency virus (HIV), in order to assess the contribution of soluble CD-2 molecules to the immunological deterioration of these patients. The serum CD-2 concentration was determined by an enzyme-linked immunosorbent assay, using a monoclonal CD-2 antibody. Considerable levels of CD-2 were detected in the sera of 15.9% of 63 normal controls tested, with a mean absorbance at 492 nm of 0.154 +/- 0.033. In contrast, in none of the 13 asymptomatic HIV-infected individuals tested could soluble CD-2 be detected (mean absorbance of 0.00093 +/- 0.0048). Elevated concentrations of CD-2 were found in the sera of 3 of 12 patients tested who were suffering from acquired immunodeficiency syndrome (AIDS). Thus, following HIV infection there is an initial phase of reduction of soluble CD-2, probably reflecting diminished T-cell activation. Thereafter, in some AIDS patients episodes of T-cell destruction seem to be correlated with the release of CD-2 molecules into the serum.