CD4 MASKING DURING HUMAN-IMMUNODEFICIENCY-VIRUS TYPE-1 INFECTION, QUANTIFIED ON PERIPHERAL-BLOOD LYMPHOCYTES, IS A POTENTIAL MARKER OF DISEASE PROGRESSION

In human immunodeficiency virus type 1 (HIV-1)-infected adults, the pr oportion of gp120-free CD4 molecules on the surface of T lymphocytes w as measured by double-epitope EIA and expressed as a CD4 epitope conce ntration ratio. In 51% of these patients (n = 81), CD4 T cells showed a significant decrease (up to 100%) in the accessibility of the CD4 ep itope corresponding to the gp120 binding site (CDR2-like region), wher eas another epitope in the D1 domain remained accessible. Of interest, a significant increase in the CD4 gp120 binding site concentration, w ithout a change in T cell counts, was observed within 10 days after in itiation of zidovudine treatment. Furthermore, CD4 masking by gp120 wa s associated with a poor clinical patient status. The assessment of th e CD4 epitope concentration ratio is proposed as a surrogate marker of disease progression in HIV-1-infected patients.