Prognostic significance of hepatitis C virus RNA detection by transcription-mediated amplification with negative polymerase chain reaction during therapy with peginterferon alpha and ribavirin

[To consider negative viral loads below the limit of quantification can lead to errors in the diagnosis and treatment of hepatitis C virus infection]

INTRODUCTION

For years many clinical laboratories have routinely classified undetectable and unquantifiable levels of hepatitis C virus RNA (HCV-RNA) determined by RT-PCR as below limit of quantification (BLOQ). This practice might result in erroneous clinical decisions.

AIM

To assess the frequency and clinical relevance of assuming that samples that are BLOQ are negative.

MATERIAL AND METHOD

We performed a retrospective analysis of RNA determinations performed between 2009 and 2011 (Cobas/Taqman, lower LOQ: 15 IU/ml). We distinguished between samples classified as «undetectable» and those classified as «<1.50E+01IU/mL» (BLOQ).

RESULTS

We analyzed 2.432 HCV-RNA measurements in 1.371 patients. RNA was BLOQ in 26 samples (1.07%) from 23 patients (1.68%). BLOQ results were highly prevalent among patients receiving Peg-Riba: 23 of 216 samples (10.6%) from 20 of 88 patients receiving treatment (22.7%). The clinical impact of BLOQ RNA samples was as follows: a) 2 patients initially considered to have negative results subsequently showed quantifiable RNA; b) 8 of 9 patients (88.9%) with BLOQ RNA at week 4 of treatment later showed sustained viral response; c) 3 patients with BLOQ RNA at weeks 12 and 48 of treatment relapsed; d) 4 patients with BLOQ RNA at week 24 and/or later had partial or breakthrough treatment responses, and e) in 5 patients the impact were null or could not be ascertained.

CONCLUSIONS

This study suggests that BLOQ HCV-RNA indicates viremia and that equating a BLOQ result with a negative result can lead to treatment errors. BLOQ results are highly prevalent in on-treatment patients. The results of HCV-RNA quantification should be classified clearly, distinguishing between undetectable levels and levels that are BLOQ.

Hepatitis C virus viral assays in the direct-acting antiviral era

In the direct-acting antiviral (DAA) era of hepatitis C virus (HCV) therapy, health care providers must be knowledgeable about genotype and subtype of HCV infection and interpretation of quantitative HCV viral assays to monitor treatment responses. They may also choose to assess interleukin 28B genotypes or resistance-associated variants after ineffective DAA therapy. DAA therapies require understanding of performance characteristics of quantitative HCV RNA assays and the definitions of terms used to report results. Only quantitative HCV RNA assays with a limit of detection of 10 to 15 IU/mL are appropriate for managing patients on DAA therapy.

Clinical significance of discordant positive hepatitis C virus transcription-mediated amplification following end of treatment response

BACKGROUND

Polymerase chain reaction (PCR) assays are the standard for detecting hepatitis C virus viremia. The transcription-mediated amplification (TMA)-based assay is more sensitive.

METHODS

We retrospectively reviewed the charts of patients with a post-end of treatment (EOT) PCR-/TMA+ result to assess the clinical significance of a positive TMA result after a PCR negative EOT response or sustained viral response (SVR). Patients were divided into Group 1: PCR-/TMA+ after EOT response but during 24 week follow-up (n = 4); and Group 2: PCR-/TMA+ after SVR (n = 11).

RESULTS

All Group 1 patients achieved SVR. No Group 2 patients became PCR positive or had a rise in ALT. The TMA subsequently became negative in 6/7 patients with follow-up evaluation.

CONCLUSIONS

A discordant positive TMA post-EOT response or SVR did not seem to be clinically significant. This finding supports the possibility that patients with SVR have an acquired immune surveillance that prevents low-level viremia from progressing to clinical relapse.

Hepatitis C virus RNA assays: current and emerging technologies and their clinical applications

Molecular diagnostic assays represent a cornerstone in the management of hepatitis C virus (HCV) patients. Qualitative and quantitative HCV molecular assays are used for the diagnosis of acute and chronic HCV infections, viral genotyping, viral-load determination, treatment monitoring and prognosis. Reverse-transcription PCR, transcription-mediated amplification and branched DNA amplification are commonly employed for detection of HCV RNA. Recently, new HCV molecular assays that employ nanostructures have emerged and have been proposed as suitable for both low- and high-resource settings, without sacrificing sensitivity and specificity. This article will present current and future HCV molecular diagnostic assays with a focus on their clinical applications.

Elevations in alanine aminotransferase levels late in the course of antiviral therapy in hepatitis C virus RNA-negative patients are associated with virological relapse

The incidence and clinical meaning of elevated alanine aminotransferase (ALT) in chronic hepatitis C patients who are hepatitis C virus (HCV)-RNA negative during pegylated interferon (PEG-IFN) and ribavirin therapy have not been completely characterized. In this study our aim was to assess the incidence, pattern, predictive factors, and clinical meaning of elevated ALT in a cohort of 173 chronic hepatitis C patients who obtained viral clearance during either PEG-IFNalpha2(a) or alpha2(b) and weight-based ribavirin therapy. Patients were defined sustained viral responders (SVRs) or relapser responders (RRs) on the basis of a serum HCV-RNA result at 24-week follow-up. SVR and RR were obtained in 141 (58%) and 32 patients (13%), respectively. Among the 173 study patients, 57 patients (33%) had undetectable serum HCV-RNA and elevated ALT in at least one evaluation (weeks 2, 4, 12, 24 in all genotypes, and week 48 in HCV genotype 1 and 4 alone), and this phenomenon was not differently distributed between SVRs and RRs. No pretreatment demographic (age, gender), clinical (ALT levels, histological grade and stage, body mass index) and viral (load, genotype) parameter was associated with this phenomenon. The incidence of elevated ALT levels was not associated with type of PEG-IFN and ribavirin dose. Elevated ALT levels showed a different longitudinal pattern, occurring more frequently between week 12 and the end of treatment in RR as compared to SVR patients (90% versus 9%, P = 0.000001).

CONCLUSION

The occurrence of elevated ALT levels in HCV-RNA-negative patients during PEG-IFN and ribavirin therapy is a fairly frequent and unpredictable phenomenon. Although ALT elevation per se is not associated with a greater risk of relapse, its occurrence in the later phases of therapy is more common in relapsing patients.

Molecular diagnostics of infectious diseases

PURPOSE OF REVIEW

The purpose of this article is to review the molecular methods commonly used in medical microbiology as well as to update the clinician as to newer molecular technologies that show promise in the identification of microorganisms as well as evaluation of the presence of virulence factors and antibiotic resistance determinants.

RECENT FINDINGS

Numerous molecular assays have been developed recently using a variety of technologies. Direct hybridization techniques have allowed analysis of blood culture bottles for organisms such as methicillin-resistant Staphylococcus aureus. Target amplification methods allow postamplification analysis using a variety of technologies depending on the clinical needs for the assay. Postamplification analysis includes methods such as Sanger sequencing, pyrosequencing, reverse hybridization, and Luminex analysis, which are becoming more widely utilized. In the future, whole genome sequencing, mass spectrometry, and microarray analysis may provide a wealth of information that can be used to specifically tailor the treatment of infectious diseases.

SUMMARY

The implications of current trends in molecular infectious diseases are moving towards high-throughput, simple, array-type technologies that will provide a wealth of data regarding types of organisms present in a sample and the virulence factors/resistance determinants that influence the severity of disease. As a result of these developments, infectious diseases will be more accurately and effectively treated.

Interpretation of positive transcription-mediated amplification test results from polymerase chain reaction-negative samples obtained after treatment of chronic hepatitis C

The Siemens VERSANT transcription-mediated amplification (TMA) assay is extremely sensitive for the detection of hepatitis C virus (HCV) RNA in serum. Eleven of 180 subjects in the Hepatitis C Antiviral Long-term Treatment against Cirrhosis (HALT-C) Trial who achieved polymerase chain reaction (PCR)-defined sustained virological response (SVR) at week 72 also had TMA-positive results from the same blood draw; six were positive on repeat testing. We report the follow-up on these 11 patients, and the reproducibility of TMA test results from PCR-negative samples in relationship to antiviral treatment outcome. Peginterferon and ribavirin treatment was initiated in 1145 prior interferon nonresponders with advanced hepatic fibrosis. Treatment was continued for 48 weeks if patients had undetectable HCV RNA by PCR at treatment week 20. Frozen serum samples from weeks 12, 20, 24, 48, and 72 were subsequently tested by TMA. Nine of the 11 patients returned for testing (median, 30 months after the week 72 visit), and all had undetectable HCV RNA by TMA and PCR. Among 759 PCR-negative samples obtained during treatment that were tested twice by TMA, 17% overall exhibited consistently positive results, and 21% exhibited inconsistently positive results. SVR was more likely if TMA was consistently negative than if consistently or inconsistently positive. With continued treatment, patients with inconsistently positive TMA results were more likely to become TMA-negative than TMA-positive (P < 0.0001).

CONCLUSION

In PCR-negative samples, positive TMA results may indicate the presence of low levels of HCV RNA. However, because patients with positive TMA results may achieve SVR, management decisions during therapy should not be based on a single positive TMA test result.