12th International AIDS Conference Geneva, Switzerland - June 28-July 3, 1998

Int Conf AIDS 1998 Jun 28-Jul 3; 12:11 (abstract no. 11146)

Klein A, Kupfer B, Brackmann HH, Rockstroh JK, Kasper P, Matz B, Kaiser R
Institut F. Medizinische Mikrobiologie, Bonn, Germany.

BACKGROUND: In 1989/90 eight hemophilia B patients were clonally infected with HIV-1 from one lot of clotting factor concentrate. The evolution of these initially unique viral strains was observed and followed-up by analyses of several viral sequences (env-V3 and V1/2, vif, and gap-p17).

OBJECTIVES: The divergent courses of disease could not be correlated to HIV-1 sequence diversifications as analyzed so far. To investigate, whether the progress in clinical course is correlated to diversifications in HIV-1 regulatory genes, we have analyzed the nef-gene and the vpu-gene in six clonally infected patients.

METHODS: Nef- and vpu-specific PCR-products were generated from longitudinal samples of proviral DNA and from viral plasma RNA of 6 clonally infected patients. Genotypes were analyzed by solid phase sequencing of the amplicons. HIV-1 RNA was quantified using the NASBA HIV-1 QT system. Viral phenotypes were determined by peripheral blood mononuclear cell (PBMC)-cocultivation. CD4+ T-cells were quantified by flow cytometry.

RESULTS: Vpu showed a heterogeneous distribution of mutations. Most mutations occurred in the region encoding the transmembrane domain (TMD), however the hydrophobic character was not affected. The cytoplasmic domains were more conserved. The TMD and the C-terminus showed a parallel evolution. In 4 of 6 patients an insertion in the nef-gene was observed. In 2 isolates a disrupted nef open reading frame was noticed. The genetic evolution within the nef-gene was not directed. No correlation was found between the different genetic variations and viral load or CD4(+)-cell count.

CONCLUSIONS: Although the patients were clonally infected, the clinical course, viral load and CD4(+)-cell count differed significantly. In all patients vpu seemed to be biologically active. Vpu and nef showed advanced but different diversification. Within these genes some regions were subjected to a higher selection pressure than others.

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