Long term non-progressor patients (LTNPs) are characterized by the natural control of HIV-1 infection. This control is related to host genetic, immunological and virological factors. In this work, phylogenetic analysis of the proviral nucleotide sequences in env gene from a Spanish HIV-1 LTNPs cohort identified a cluster of 6 HIV-1 controllers infected with closely-related viruses. The patients of the cluster showed common clinical and epidemiological features: drug user practices, infection in the same city (Madrid, Spain) and at the same time (late 70’s-early 80’s). All cluster patients displayed distinct host alleles associated with HIV control. Analysis of the virus envelope nucleotide sequences showed ancestral characteristic, lack of evolution and presence of rare amino-acids. Biological characterization of recombinant viruses with the envelope proteins from the cluster viruses showed very low replicative capacity in TZMbl and U87-CD4/CCR5 cells. The lack of clinical progression in the viral cluster patients with distinct combinations of protective host genotypes, but infected by low replicating viruses, indicate the important role of the virus in the non-progressor phenotype in these patients.

We studied viral evolution in three HIV-1 ancestral patients from a group of LTNPs; although some minor sequences showing viral evolution were detected in all patients, the extremely low viral evolution of their viruses was shown by the phylogenetic analysis of the env sequences. Complete nucleotide sequencing of viral DNA showed the major presence of deletions. In two patients, deletions of 1088 and 228 nucleotides mapped to 5' LTR-gag region; in the other, a 247 nucleotide deletion was positioned in pol gene up to the vif ORF. These deleted genomes became dominant during follow up. Patient's viruses displayed 13 common mutations in conserved residues, from the 5' LTR to the nef gene. These mutations provided evidence of a common origin. Regarding host characteristics, one patient had HLA B2705/B5801; another B1402/B5701; whereas a third showed B3901/B4402 and was Delta32-CCR5 heterozygous. These HIV controllers presented a combination of deleted viral genomes and host protective factors.

A subset of human immunodeficiency virus type 1 long-term non-progressors is characterized by the unique presence of ancestral sequences in the viral population b 2 m level, and they were also associated with better use of safe-sex practices and higher presence of the HLA sB58 supertype than the modern subset. Viral dating has therefore permitted the segregation of LTNPs into two subsets that show very different virological, immunological, host and clinical-epidemiological characteristics. Moreover, whereas the modern subset displayed low levels of virus replication, the ancestral group displayed not only a very limited virus replication, often to undetectable levels, but also very slow or arrested viral evolution, maintaining the close relationship of the viral population to the transmitted virus. INTRODUCTIONThe natural history of human immunodeficiency virus type 1 (HIV-1) infection is heterogeneous because of the diverse duration of the AIDS-free period, although the median time of appearance of AIDS clinical symptoms is between 8 and 10 years after infection (Bacchetti & Moss, 1989; Hendriks et al., 1993; Muñoz et al., 1989). However, cohort studies have identified a small fraction of infected people, about 5-10 % (Buchbinder et al., 1994;Keet et al., 1994; Lefrère et al., 1997; Sheppard et al., 1993), who, despite infection for more than 10 years, remain symptomless and maintain a relatively high CD4 + cell count (>500 CD4 + cells ml 21 ) without antiviral therapy (Buchbinder et al., 1994;Keet et al., 1994;Learmont et al., 1992;Lifson et al., 1991; Sheppard et al., 1993). Different designations have been used for these patients, such as non-progressors (Lifson et al., 1991; Sheppard et al., 1993), long-term survivors (Levy, 1993), long-term asymptomatics (Keet et al., 1994) and long-term non-progressors (LTNPs) (Buchbinder et al., 1994).LTNPs have been associated with a low viral burden (Barker et al., 1998;Cao et al., 1995;Hogervorst et al., 1995;Pantaleo et al., 1995;Rinaldo et al., 1995) and a strong cellular (Barker et al., 1998;Cao et al., 1995;Harrer et al., 1996;Hogervorst et al., 1995;Klein et al., 1995;Pantaleo et al., 1995;Rinaldo et al., 1995)