Conversion rate towards a syncytium-inducing (SI) phenotype during different stages of human immunodeficiency virus type 1 infection and prognostic value of SI phenotype for survival after AIDS diagnosis

The presence of syncytium-inducing (SI) human immunodeficiency virus type 1 (HIV-1) variants is predictive for accelerated progression to AIDS. This s tudy showed that a 4-year survival with AIDS also occurred significantly mo re often for patients who lacked SI variants. However, multivariate Cox ana lysis excluded the predictive value of SI viruses for rapid death as being independent from low CD4(+) T cell counts. Incidence of appearance of Sr va riants was increased in persons with CD4(+) T cell counts <500/mu L but rem ained constant in the strata of CD4(+) T cell counts <500/mu L, excluding t he possibility that loss of immune control is the only prerequisite for the development of SI HIV-1 variants.