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8th Annual Conference Of The British HIV Association [BHIVA]19 – 21 April 2002, University of York, York |
[AUTHOR(S):] Y Mazen, AL Pozniak, D Pillay, S Mandalia, A Wildfire, BG Gazzard
Chelsea and Westminster Hospital, London, UK
BHIVA Conf 2002 Apr 19-21;8:O11
INTRODUCTION: A viral load between 50 and 400 copies/mL in patients previously undetectable (<50 copies/mL) on highly active antiretroviral therapy (HAART) may be due to laboratory factors, a true virological blip or the portent of imminent virological failure. We have examined whether low level viraemia (LLV) values are repeatable on the same sample and whether there is evidence of prior ongoing virological replication in those who subsequently fail virologically (viral load >400 copies/mL).
METHODS: Patients on stable HAART who had at least two values of viral load <50 copies/mL (Chiron assay), then >50 but <400 copies/mL (LLV) and subsequently became undetectable (<50 copies/mL) had their viral loads remeasured on the same plasma sample. Those whose repeated value was still >50 but <400 copies/mL were called repeatable blips (RB), and those with a repeat <50 copies/mL were called non-repeatable blips (NRB). These were compared with a group who developed >400 copies/mL immediately after the LLV sample, called the viral failure (VF) group. The optical density normalized for background was measured in at least two samples of <50 copies/mL prior to LLV as an indirect measure of ongoing viral replication.
RESULTS: Of 247 blip patients, 102 patients were RB (41%) and 145 were NRB (59%). 139 were in the VF group. At the time of LLV there was a significant difference in viral load between the VF group and both NRB and RB groups (P<001) There was evidence of greater ongoing viral replication at <50 copies/mL in the VF group from samples taken a median of 5.8 and 2.8 months before LLV. This was not seen in the NRBs, but in the RB group, the sample immediately prior to the LLV showed evidence of viral replication as well, but not in the previous sample taken at a median of 5.6 months.
CONCLUSION: 59% of all blips are non-repeatable on the same sample.
PRESENTING AUTHOR: Y Mazen
020419
O11
Copyright © 2002 - British HIV Association (BHIVA) Reproduction of this abstract (other than one copy for personal reference) must be cleared through the BHIVA Organising Secretariat 1 Mountview Court, 310 Friern Barnet Lane, London N20 0LD