The aim of this study was to detect and determine the genetic variation of
HIV-1 in Greece and to analyze the phylogenetic relationships and transmiss
ion dynamics of identified variants. Eighty-six blood samples from HIV-1 se
roconverted patients of different risk groups were collected from the AIDS
clinic, AHEPA Hospital, Thessaloniki, Greece. Retroviral DNA was extracted
from uncultured peripheral blood mononuclear cells. HIV-1 DNA sequences enc
oding a 500-bp fragment of the gp120 C2-C3 region were amplified from each
study subject, and they were genetically subtyped by heteroduplex mobility
assay and DNA sequencing. Genetic distances and phylogenetic relationships
of DNA sequences were estimated using PHYLIP software. Our results revealed
that 82 out of 86 (95%) subjects carried subtype B sequences, while four (
4.7%) carried subtype A sequences. Subtype A in Greek individuals not havin
g traveled abroad was documented. An average of intrasubtype B genetic dive
rgence of 15% was noted. Our findings demonstrate the presence of at least
two genetic subtypes of HIV-1 in northern Greece - subtype B and subtype A.
The predominant subtype is subtype B, which was transmitted into Greece by
multiple sources. Our observations lend support to the argument that the d
istribution of HIV-1 subtypes is determined by founder effects or other pro
cesses rather than any tropism for particular cell types or mode of transmi
ssion. (C) 2000 Editions scientifiques et medicales Elsevier SAS.