Title
Genotypic tropism testing by massively parallel sequencing: qualitative and quantitative analysis.
Abstract
Inferring viral tropism from genotype is a fast and inexpensive alternative to phenotypic testing. While being highly predictive when performed on clonal samples, sensitivity of predicting CXCR4-using (X4) variants drops substantially in clinical isolates. This is mainly attributed to minor variants not detected by standard bulk-sequencing. Massively parallel sequencing (MPS) detects single clones thereby being much more sensitive. Using this technology we wanted to improve genotypic prediction of coreceptor usage.Plasma samples from 55 antiretroviral-treated patients tested for coreceptor usage with the Monogram Trofile Assay were sequenced with standard population-based approaches. Fourteen of these samples were selected for further analysis with MPS. Tropism was predicted from each sequence with geno2pheno[coreceptor].Prediction based on bulk-sequencing yielded 59.1% sensitivity and 90.9% specificity compared to the trofile assay. With MPS, 7600 reads were generated on average per isolate. Minorities of sequences with high confidence in CXCR4-usage were found in all samples, irrespective of phenotype. When using the default false-positive-rate of geno2pheno[coreceptor] (10%), and defining a minority cutoff of 5%, the results were concordant in all but one isolate.The combination of MPS and coreceptor usage prediction results in a fast and accurate alternative to phenotypic assays. The detection of X4-viruses in all isolates suggests that coreceptor usage as well as fitness of minorities is important for therapy outcome. The high sensitivity of this technology in combination with a quantitative description of the viral population may allow implementing meaningful cutoffs for predicting response to CCR5-antagonists in the presence of X4-minorities.
Year
DOI
Venue
2011
10.1186/1472-6947-11-30
BMC Med. Inf. & Decision Making
Keywords
Field
DocType
phenotype,false positive rate,health informatics,viral tropism,genotype
Massive parallel sequencing,Tropism,Data mining,Genotype,Maraviroc,Tissue tropism,Computational biology,Virology,Medicine
Journal
Volume
Issue
ISSN
11
1
1472-6947
Citations 
PageRank 
References 
0
0.34
0
Authors
6
Name
Order
Citations
PageRank
Martin Däumer18815.64
Rolf Kaiser221347.27
Rolf Klein300.34
Thomas Lengauer43155605.03
Bernhard Thiele500.34
Alexander Thielen6111.51