Transmission of multidrug-resistant HIV-1: 5 years of immunological and virological survey.

Multidrug resistant HIV-1 acquired at the time of primary infection in two patients persisted for at least 5 years with and without treatment. In each patient, only one back mutation to wild-type codon in the protease gene occurred, and that was concomitantly associated with a marked CD4 cell count decrease. In both cases, infection was caused by CCR5 viruses and no rapid clinical progression to AIDS after primary infection was observed.