final program.qxd - Parallels Plesk Panel

SS 1.1
The importance of HIV drug resistance testing in daily practice
Vincent Soriano
Department of Infectious Diseases, Hospital Carlos III, Madrid, Spain
Background
Optimal care of antiretroviral therapy in HIV-infected individuals requires the integration of
CD4 counts, plasma HIV-RNA and drug resistance testing. Recent guidelines
recommends resistance testing before initiation of antiretroviral therapy, since 10-15% of
drug-naïve individuals may harbour drug resistance as consequence of transmission of
resistant viruses. Drug resistance testing is also required to optimize rescue interventions
in patients experiencing virological failure under any treatment regimen.
Patients and Methods
The resistance database of Hospital Carlos III records clinical information along with
resistance mutations in samples submitted from different hospitals across Spain since
year 1996. Several studies of prevalence, trends over time and clinical correlates of
resistance mutations have been performed over the last decade in HIV-1 seroconverters,
chronically drug-naïve individuals, persons infected with non-B subtypes and treatmentexperienced
patients.
Results
Nearly 4,000 genotypes have been recorded until mid 2006, of whom 350 belongs to
HIV-1 seroconverters, 300 to chronically drug-naïve individuals and the remaining vast
majority to antiretroviral-experienced patients. Real and/or virtual phenotypes are
available for a substantial number of samples. Clinical correlates (viral load and CD4
counts) following antiretrovirals used after genotyping are available for nearly 2000
patients. Among the main findings are the original recognition of the antagonism between
rtK65R and TAMs, the role of proI47A in causing lopinavir resistance, and the differential
transmission of drug resistance mutations.
Conclusions. Drug resistance will continuous to challenge HIV therapy. A better
knowledge of the mechanisms of resistance by clinicians and how to optimally use
resistance information will translate in a better HIV management. Both phenotypic and
clinical correlates of drug resistance mutations will help to interpret more appropriately
resistance mutations for the older and new coming antiretrovirals.
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