Prevalence and virologic consequences of HIV-1 genotype mutations detected in a cohort of 161 Italian patients receiving a nelfinavir-based highly active antiretroviral therapy

[Study of resistance using the TRUGENE HIV-1 genotyping system and analysis of agreement between rule-based algorithms and virtual phenotyping]

INTRODUCTION

This study attempts to describe the results obtained in the HIV resistance study performed with clinical samples obtained from patients receiving "HAART" therapy and to compare the results using different interpretation algorithms.

METHODS

397 samples have been analysed (TRUGENE HIV-1 GENOTYPING kit). The results were interpreted with the algorithms Visible Genetics and Retrogram. The concordance interalgorithm was done for 105 of these samples, including the virtual phenotype interpretation.

RESULTS

The samples corresponded to multi regimen failure (39%), first and second failure (30.7% and 27.1% respectively). A 27.6% of the samples were wild type. The more frequent mutations to the ITIAN were T215Y/F (37.2%) and M184V (32.9%) following by other NAMS. The 69 insertion and Q151M complex had low representativity. For the ITINN K103N (25.8%), Y181C (11.2%) and G190A (10.9%). For the IP: key mutations L90M (26.1%), M46I (18.1%) and V82AFTS (12.9%); and accessory mutations L63P (50.5%), A71V (27.2%), L10I (25.2%) and M36I (19.2%). Low correlation was observed between interpretation systems, mainly for ITIAN and IP, being the virtual phenotype more flexible in the assignation of resistance.

CONCLUSIONS

The requests for HIV resistance testing were similar for the three groups of patients. Many of the failures were the consequence of a poor adherence to the therapy. The mutation pattern found corresponded with the "TARGA" therapy. The low correlation found between interpretation systems, makes necessary the elaboration of a consensus algorithm.