Comparison of mass spectrometric analysis and TRUGENE HBV genotyping for monitoring lamivudine resistance in chronic hepatitis B patients.
BACKGROUND
There is an increasing need for the early detection of emerging mutations in the tyrosine-methionine-aspartate-aspartate (YMDD) motif of hepatitis B virus (HBV) DNA polymerase with using sensitive molecular methods.


METHODS
We evaluated the usefulness of monitoring lamivudine resistance using a matrix-assisted laser desorption/ionization time-of-flight mass spectrometry-based assay (the restriction fragment mass polymorphism; RFMP) in comparison with the direct sequencing assay, the TRUGENE ' HBV genotyping kit. We also investigated the treatment responses in relation to the presence of YMDD mutants. The sera from 50 chronic HBVs patients were analysed for the presence of YMDD mutants by performing RFMP and TRUGENE. The results at codons 180 and 204 were compared for 46 patients.


RESULTS
The concordance rate between the two assays was 65.2% (30/46). All the discordance corresponded to the detection of additional virus populations by RFMP. Early detection of mutants before viral breakthrough was accomplished by RFMP in two patients. Persistence of very low viraemia was observed in five patients who harboured mutant virus populations. Additional information was provided by TRUGENE in eight patients.


CONCLUSIONS
RFMP showed a superior ability for detecting minor mutant virus populations compared with TRUGENE. However, the results of highly sensitive RFMP should be interpreted carefully because lamivudine could be effective despite the presence of mutants. RFMP could be a practical tool in conjunction with regular measurements of the HBV viral load for the early detection of lamivudine resistance and the timely introduction of new antiviral drugs.
Woo
Hee-Yeon
HY
Department of Laboratory Medicine, Kangbuk Samsung Hospital, Sungkyunkwan University School of Medicine, Seoul, Korea.
Park
Hyosoon
H
Kim
Byung-Ik
BI
Jeon
Woo-Kyu
WK
Cho
Yong Kyun
YK
Kim
Young Jae
YJ
D000328:Adult; D000368:Aged; D020816:Amino Acid Motifs / Q000235:genetics; D003062:Codon; D004252:DNA Mutational Analysis / Q000379:methods*; D004279:DNA, Viral / Q000097:blood*; D004259:DNA-Directed DNA Polymerase / Q000097:blood / Q000235:genetics; D016903:Drug Monitoring / Q000379:methods; D024882:Drug Resistance, Viral / Q000235:genetics*; D005260:Female; D005838:Genotype; D006515:Hepatitis B virus / Q000201:enzymology / Q000235:genetics*; D019694:Hepatitis B, Chronic / Q000097:blood / Q000175:diagnosis* / Q000188:drug therapy / Q000235:genetics; D006801:Humans; D019259:Lamivudine / Q000627:therapeutic use*; D008297:Male; D008875:Middle Aged; D009154:Mutation; D012150:Polymorphism, Restriction Fragment Length; D011237:Predictive Value of Tests; D018894:Reverse Transcriptase Inhibitors / Q000627:therapeutic use*; D012680:Sensitivity and Specificity; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization / Q000379:methods*; D016896:Treatment Outcome; D019562:Viral Load
D003062:Codon; D004279:DNA, Viral; D018894:Reverse Transcriptase Inhibitors; D019259:Lamivudine; D004259:DNA-Directed DNA Polymerase