Five human immunodeficiency virus type 1 phenotypic variants with different MT-2 cell tropisms correlate with prognostic markers of disease

OBJECTIVES: We correlated virologic and immunologic parameters of disease progression with cytopathogenicity of HIV isolates. STUDY DESIGN/METHODS: Human immunodeficiency virus type 1 (HIV-1) isolates from 207 patients with CD4+ cell counts < 500/mm3 were examined for biologic phenotype in MT-2 cells. We used a cross-sectional study design. RESULTS: Three subtypes of syncytium-inducing (SI) strains with different times of appearance of syncytia formation in cell culture and two subtypes of non-syncytium-inducing (NSI) isolates, with (NSI/MT2+) or without (NSI/MT2-) replicative capacity in MT-2 cells, were identified. Early SI strains were associated with the lowest CD4+ cell counts and the highest levels of viral load, and NSI/MT2- isolates correlated with the highest CD4+ cell counts and the lowest viral loads. Patients with late SI and NSI/MT2+ strains showed minimal differences in immunologic and virologic markers. CONCLUSIONS: Five HIV phenotypic variants that correlate significantly (P < 0.001) with markers of disease progression were identified.