Microwave treatment of serum facilitates detection of hepatitis B virus DNA by the polymerase chain reaction. Results of a study in anti-HBe positive chronic hepatitis B

A comparative study of extraction free detection of HBV DNA using sodium dodecyl sulfate, N-lauroylsarcosine sodium salt, and sodium dodecyl benzene sulfonate

This study aimed to develop an extraction-free method for quantitative and qualitative detection of HBV DNA compared to traditional nucleic acid extraction. Paired serum and dried blood spot (DBS) samples from 67 HBsAg-positive and 67 HBsAg-negative individuals were included. Two samples with known HBV DNA titers (~ 109 copies/mL) were examined by extraction-free detection using three surfactants (0.2 to 1% of Sodium dodecyl sulfate:SDS, N-Lauroylsarcosine sodium salt:NL, Sodium dodecyl benzene sulfonate:SDBS), two stabilizing agents (0.1 or 0.01% 2-Mercaptoethanol:2ME and 3.5 or 7% Bovine Serum Albumin:BSA) and two Taq polymerases (Fast Advanced and Prime Direct Probe). HBV DNA in all 67 HBsAg-positive and 67 HBsAg-negative serum and DBS samples was directly quantified by Rt-PCR using 0.4% SDS or 0.4% NL with Fast Advance or Prime Direct Probe Taq. Extraction-free amplification was also performed. Detection limits were varied by different surfactants and Taq. SDS combined with Fast Advanced Taq showed lower detection limits, while SDS with Prime Direct Probe Taq outperformed NL or SDBS-based detection. Adding 2ME to SDS improved detection limit with Prime Direct Probe Taq but not significantly compared to SDS alone. BSA did not significantly enhance detection limits but provided insights into sample stability. The senitivity and specificity of 0.4% SDS and NL in combination with either Fast advanced or Prime Direct Probe Taq polymerase in serum samples were > 90% and 100% resepctively, while it was > 80% and 100% respectively in DBS samples. Extraction-free HBV DNA amplification provided 100% identity with original genomes. Our study suggests that SDS, NL or SDBS-based extraction-free HBV DNA detection strategies using Prime Direct Probe Taq have potential to simplify and accelerate HBV DNA detection with high sensitivity and specificity in both serum and DBS samples, with implications for resource-limited settings and clinical applications. Utilizing surfactants with 2ME is optional, and further research and validation are necessary to broaden its application in real-world diagnostics.

Advances in Directly Amplifying Nucleic Acids from Complex Samples

Advances in nucleic acid amplification technologies have revolutionized diagnostics for systemic, inherited, and infectious diseases. Current assays and platforms, however, often require lengthy experimental procedures and multiple instruments to remove contaminants and inhibitors from clinically-relevant, complex samples. This requirement of sample preparation has been a bottleneck for using nucleic acid amplification tests (NAATs) at the point of care (POC), though advances in “lab-on-chip” platforms that integrate sample preparation and NAATs have made great strides in this space. Alternatively, direct NAATs—techniques that minimize or even bypass sample preparation—present promising strategies for developing POC diagnostic tools for analyzing real-world samples. In this review, we discuss the current status of direct NAATs. Specifically, we surveyed potential testing systems published from 1989 to 2017, and analyzed their performances in terms of robustness, sensitivity, clinical relevance, and suitability for POC diagnostics. We introduce bubble plots to facilitate our analysis, as bubble plots enable effective visualization of the performances of these direct NAATs. Through our review, we hope to initiate an in-depth examination of direct NAATs and their potential for realizing POC diagnostics, and ultimately transformative technologies that can further enhance healthcare.

Anti-viral therapy can be delayed or avoided in a significant proportion of HBeAg-negative Caucasian patients in the Grey Zone

BACKGROUND

Grey Zone (GZ) is an ill-defined situation including patients falling between inactive carrier (IC) state and HBeAg-negative chronic hepatitis B (HBeAg-negative CHB).

AIMS

To assess the long-term outcomes of GZ patients compared to IC in the absence of treatment.

METHODS

Retrospective analysis of 287 IC and GZ HBeAg-negative patients. Patients were classified into 4 groups at baseline: HBV-DNA <2000 IU/mL and ALT <40 U/L (IC), HBV-DNA <2000 IU/mL and ALT 40-80 U/L (GZ-1), HBV-DNA 2000-20 000 IU/mL and ALT <40 U/L (GZ-2) or ALT 40-80 U/L (GZ-3). Data were also analysed using AASLD ALT criteria.

RESULTS

After a median follow-up of 8.2 (5-19) years, HBsAg loss occurred in about 15% ICs or GZ patients. Transition into IC state occurred in 40% of GZ patients. DNA fluctuations >2000 IU/mL correlated inversely with transition into IC and HBsAg loss. HBsAg levels were significantly lower in ICs than in GZ patients (338 IU/mL [20-3269] vs 5763 IU/mL [2172-17 754]; P < 0.05). Among the latter group, there was an increasing gradient of HBsAg levels from GZ-1 to GZ-3 patients (P < 0.05). HBeAg-negative CHB occurred in only 18 (6.3%) GZ patients. No patient developed cirrhosis nor advanced fibrosis. ALT/HBV-DNA fluctuations and HBeAg-negative CHB development were more frequent in genotype B/C patients, whereas HBsAg loss occurred only in genotype A/D patients.

CONCLUSIONS

Most Caucasian GZ patients present excellent long-term outcomes in the absence of treatment, with a high rate of HBsAg loss and low rate of progression to HBeAg-negative CHB. HBV-genotyping and HBsAg levels could help to predict outcomes and better classify GZ patients.

A reliable and rapid method for molecular detection of malarial parasites using microwave irradiation and loop mediated isothermal amplification

Background

Improved living conditions together with appropriate diagnosis can reduce avoidable malarial deaths substantially. Microscopy remains the gold standard in the diagnosis of malaria. However, rapid molecular diagnostic tests (RmDT) are becoming increasingly important and will, most likely, be the diagnostic techniques of choice in the next years.

Methods

In this study, a rapid and reliable nucleic acid extraction procedure from human blood and malarial parasites using microwave irradiation as a promising platform is described. In addition, a tailored loop mediated isothermal amplification (LAMP) methodology that utilizes hydroxynaphthol blue (HNB) and Bst 2.0 DNA polymerases in molecular detection of malarial parasites is described.

Results

Following microwave irradiation for DNA isolation, conventional PCR assays were able to detect up to five malaria parasites/μl. The LAMP methodology described here was capable to detect as low as one Plasmodium falciparum parasite/μl after DNA extraction by microwave irradiation. A turnover time of 45 minutes from nucleic acid extraction to final visual read-out was achieved.

Conclusions

The described procedure offers a cheap, simple and fast method of molecular detection of malaria parasites. This test can easily be performed in basic laboratories. The methodology has been validated as a proof of concept and has specifically be developed for use at low-resource settings. Such RmDTs may aid health providers to make timely therapeutic interventions in malaria endemic regions.

An improved method for the isolation of hepatitis B virus DNA from human serum

Studies show that hepatitis B virus (HBV) DNA isolation methods vary in their efficiency to extract DNA from serum samples. The purpose of the present study was to develop an improved method for isolation of HBV DNA and compare it with commonly used HBV DNA isolation protocols. In order to develop HBV DNA isolation protocol, serum samples were collected from patients and screened for the presence of hepatitis B surface antigen, hepatitis B e antigen and HBV DNA. Highly viremic samples were pooled and used to compare commonly used HBV DNA isolation methods; namely alkaline lysis, microwave treatment, organic, inorganic with modified inorganic method. DNA isolated by these methods was detected qualitatively by polymerase chain reaction and quantitatively with competitive polymerase chain reaction (cPCR). The modified inorganic method gave maximum yield of HBV DNA followed by inorganic, organic, microwave treatment and alkaline lysis method. Our data also demonstrated a critical role of proteinase K in HBV DNA isolation. DNA isolation method described here, in combination with a reproducible and sensitive quantitative technique would further help in accurate classification of HBV infected patients, designing suitable drug regimen for treatment and monitoring antiviral treatment as well as emergence of drug resistant mutants.

Predictive factors of lamivudine treatment success in an hepatitis B virus-infected pediatric cohort: a 10-year study

BACKGROUND

Hepatitis B virus (HBV) infections are responsible for the development of chronic hepatitis in 400 million people worldwide. Currently, no consensus exists as to when treatment should be initiated for pediatric patients.

OBJECTIVES

To evaluate the risks and predictive factors of success of lamivudine treatment in children with chronic, active HBV infection.

METHODS

Forty-three children (22 male, median age 9.6 years) chronically infected with HBV and treated between 1998 and 2008 at CHU Ste-Justine (Montreal, Quebec) were included in the present chart review study. Inclusion criteria were detectable hepatitis B surface antigen and hepatitis B e antigen (HBeAg), minimum serum alanine aminotransferase (ALT) level of two times the upper limit of normal and detectable serum HBV DNA for at least three months. Patients received lamivudine for a minimum of six months (median 14 months). Genotyping was performed.

RESULTS

Lamivudine treatment was effective in 35% of cases (15 of 43) and overall virological response (during or after treatment) was achieved in 51% of patients. Three patients harboured suspected lamivudine-resistant mutations and five progressed to HBeAg-chronic HBV. Predictive factors for success of treatment were: younger age at beginning of treatment (P=0.05), elevated ALT levels throughout treatment duration (P=0.003) and loss of HBeAg during treatment (P=0.016). Asian origin did not affect treatment success or spontaneous viral control during follow-up. HBV genotype did not influence treatment success.

CONCLUSIONS

Lamivudine treatment in a carefully selected cohort of HBV patients demonstrated a good rate of success and low incidence of mutation. Younger age at the beginning of treatment and high ALT levels during treatment predicted a positive outcome.

Microwaves for chromogenic in situ hybridization

In situ hybridization can be employed in formalin-fixed, paraffin-embedded tissue sections (FFPT) and allows direct visualization of amplified genes and chromosomes in individual cell nuclei. Fluorescence in situ hybridization (FISH) is the most widely employed method, but the fluorescence preparations suffer from the main disadvantages of fading over time and poor visualization, the latter making it difficult to accurately separate invasive from in situ cancer cells. Chromogenic in situ hybridization (CISH) is a viable alternative to FISH in FFPT as it employs a peroxidase reaction to visualize the chromogen thus allowing the convenience of bright field microscopy and the correlation of the visualized gene amplification with cytomorphology. It is relatively less expensive and allows a permanent record, with several studies attesting to its validity. As with FISH, heat pretreatment and enzyme digestion are two critical components of the protocol. We describe a protocol for CISH in which a microwave-induced target retrieval step is introduced as a replacement for heat pretreatment. The same procedure is performed following enzyme digestion to produce consistent signals in amplified and nonamplified cells that are both larger in size and numbers when compared with those produced by the conventional protocol.

Microwave enhancement of CISH for HER2 oncogene

We describe a modification to the prescribed procedure for the Zymed Spot-Light HER2 chromogenic in situ hybridization kit (84-0146, Zymed Laboratories, San Francisco, CA) by substituting the heat pretreatment step with MW irradiation in citrate buffer 10 mmol/L at pH 6.0 at 98 degrees C for 10 minutes and repeating the procedure afterenzyme digestion with time and temperature controlled in the Mega T/ T oven (Milestone s.r.l., Sorisole, Italy). The subsequent procedure leading up to hybridized was as per manufacturer's instructions. Invasive breast carcinoma previously scored by immunohistochemistry for HER2, comprising 18 cases of 3+, 18 cases of 2+, and 12 cases of 1+, were examined by chromogenic in situ hybridization using this modified procedure, with a parallel set of cases examined by the prescribed Zymed method. The introduction of the "MW retrieval" steps resulted in consistently a greater number of hybridization signals in amplified tumor cells with benign epithelial cells and lymphocytes displaying 2 clear dots compared with the weaker and less consistent signals obtained with the standard procedure. MW exposed sections showed larger numbers of large and small clusters that often allowed identification of amplified tumors without having to count single dots with crisp staining and absence of background precipitation.

Influence of hepatitis B virus genotype on the long-term outcome of chronic hepatitis B in western patients

BACKGROUND & AIMS

The aim of this study was to investigate if the variable outcome of chronic hepatitis B may be related to hepatitis B virus (HBV) genotype.

METHODS

The clinical and virologic events observed over prolonged follow-up in 258 Spanish patients with chronic hepatitis B infected with different genotypes of HBV were compared.

RESULTS

The prevalence of genotype A, D, and F was 52%, 35%, and 7%, respectively. Concomitant sustained biochemical remission and clearance of HBV DNA occurred at a higher rate in genotype A- than in genotype D- (log-rank, 14.2; P = 0.002) or genotype F-infected patients (log-rank, 4.2; P = 0.03). The rate of hepatitis B surface antigen (HBsAg) clearance was higher in genotype A than in genotype D hepatitis (log-rank, 4.6; P = 0.03). Sustained remission and clearance of HBsAg were associated with infection with genotype A by Cox regression analysis. Seroconversion to antibody to hepatitis B e antigen (anti-HBe) was unrelated to HBV genotype, but the rate of sustained remission after seroconversion was higher in genotype A than in genotype D hepatitis both in patients who seroconverted to anti-HBe during follow-up (log-rank, 4.5; P = 0.03) and in patients with positive anti-HBe at baseline (log-rank, 6.66; P = 0.009). Death related to liver disease was more frequent in genotype F than in genotype A (P = 0.02) or genotype D (P = 0.002) hepatitis.

CONCLUSIONS

The long-term outcome of chronic hepatitis B is different in patients infected with HBV genotype A, D, or F.

Evidence of serious graft damage induced by de novo hepatitis B virus infection after liver transplantation

De novo hepatitis B virus (HBV) infection after orthotopic liver transplantation (OLT) is commonly believed to be a relatively benign condition, in contrast to post-OLT infection recurrence, considered a very aggressive complication. We reviewed the charts of 569 non-HBV-related OLTs performed at our institution and identified 19 patients (3%) with de novo HBV infection (appearance of hepatitis B surface antigen [HBsAg] after OLT). After a median follow-up of 25 months beyond the detection of HBsAg, 12 patients (63%) had developed serious HBV-related graft damage (cirrhosis in 6 patients, bridging chronic hepatitis in 4 patients, and fulminant hepatitis in 2 patients); 7 patients (37%) had lost their grafts; and 4 patients (21%) had died. All graft losses and deaths were related to de novo HBV infection. Similar rates of severe graft damage (62%), graft loss (38%), and death (33%) related to HBV infection were found in a concomitant series of 21 patients with recurrent HBV infection after OLT. Responses to antiviral therapy (interferon or lamivudine) were also similar in the 2 groups of patients. In 12 patients with de novo HBV infection, evidence of past HBV infection (positive serum antibody to hepatitis B core antigen and/or serum or liver tissue HBV DNA) were detected in the donor (7 patients) or recipient (5 patients). No differences were observed in the clinical course after stratification according to the attributed origin of de novo HBV infection. We conclude that de novo HBV infection after OLT is associated with high rates of morbidity and mortality, similar to those described for post-OLT HBV infection recurrence.

Hepatitis B immunoglobulin discontinuation followed by hepatitis B virus vaccination: A new strategy in the prophylaxis of hepatitis B virus recurrence after liver transplantation

It is widely agreed that hepatitis B virus immunoglobulin (HBIG) should be administered for at least 12 months to patients transplanted for hepatitis B virus (HBV)-related diseases to prevent HBV recurrence. No data are available, however, on how long this treatment should be used, and most centers currently administer HBIG on a life-long basis. Herein, we report the results of a new prophylactic strategy aiming at the discontinuation of HBIG treatment and consisting of the administration of double dose recombinant HBV vaccine (0, 1-, and 6-month schedule) to liver transplant recipients fulfilling the following criteria: (1) liver transplantation for conditions related to nonreplicative HBV infection (hepatitis B surface antigen [HBsAg] positive, hepatitis B e antigen [HBeAg] negative, and HBV DNA negative); (2) at least 18 months of HBIG administration; and (3) no HBV infection recurrence, normal or slightly altered liver graft function, and low-grade immunosuppression at the time of vaccination. Seventeen patients received HBV vaccination and 14 of them (82%) developed protective serum titers of anti-HBs (>10 IU/L). Six patients seroconverted after a first course of vaccination, whereas 8 patients required a second course (3 additional doses of vaccine). Responding patients were followed for a median of 14 months (range, 3-50) after seroconversion. During this period no HBV recurrence occurred and in only 2 patients a decrease of anti-HBs titers below 10 UI/L was observed. Our data suggest that in selected liver transplant recipients, posttransplantation HBV vaccination may be a useful and cost-effective strategy in the prophylaxis of HBV recurrence, allowing the discontinuation of life-long HBIG treatment.

Infection with a novel human DNA virus (TTV) has no pathogenic significance in patients with liver diseases

BACKGROUND/AIMS

A recently identified DNA virus, termed TT virus (TTV), has been associated with post-transfusional hepatitis, and a high prevalence of TTV infection in patients with acute or chronic liver disease of unknown etiology has been reported from Japan, but few data are available about TTV infection in other countries.

METHODS

Using hemi-nested-PCR amplification to detect TTV-DNA sequences in serum, we investigated TTV infection in blood donors and in patients with liver diseases of varied etiology.

RESULTS

The prevalence of TTV infection was 13.7% in blood donors (23/168), 18.6% in chronic hepatitis C (19/102), 28.6% in chronic hepatitis B (16/56), 29.9% in hepatocellular carcinoma (20/67), 9.1% in cryptogenic chronic liver disease (2/22) and 39.6% in fulminant hepatitis (19/48). The prevalence of TTV infection in patients with virus-induced or idiopathic fulminant hepatitis was similar. Comparison of TTV-infected and non-infected patients did not reveal significant differences concerning demographic, epidemiological or histopathological features. In patients with hepatitis C, response to interferon therapy was not related to TTV infection. Phylogenetic analysis of TTV isolates showed that at least three different types of TTV are present in Spain.

CONCLUSIONS

Our data suggest that TTV infection is frequent among blood donors and patients with acute liver disease. However, pathogenic effects associated with TTV infection were not observed.

Microwave procedures for electron microscopy and resin-embedded sections

Microwaves now have well-established applications in routine light microscopy. They are employed in tissue fixation and to accelerate a wide spectrum of staining procedures. Besides producing superior preservation of cellular antigens through microwave fixation, this form of irradiation has been employed for antigen retrieval, a procedure that has been a major factor in the optimization of immunolabelling in paraffin sections and cytological preparations. A commercial tissue processor has recently been developed which employs microwaves in a markedly accelerated, one-step processing of tissue blocks, completing the procedure within a fraction of conventional times. Microwaves have also been successfully applied in a variety of molecular techniques such as in situ hybridization and polymerase chain reaction. The adoption of microwaves in electron microscopic procedures has been slower, largely because the requirement for speed in processing is not as great, except in diagnostic samples. However, as this review will show, there are equally as many innovative applications of microwaves in electron microscopy. Microwaves have been employed for rapid processing of fine needle aspiration biopsy samples, in keeping with the requirement for speed in this method of diagnosis. Ultrafast fixation of tissue samples has resulted in the better demonstration of cellular enzymes and proteins. It has been clearly shown that microwave-stimulated on grid staining in uranyl acetate and lead citrate produces more consistent results and without background precipitation. Microwaves can be used to hasten resin polymerization and exposure to microwaves results in antigen retrieval in both resin-embedded thick sections and for immuno-electron microscopy. Immunolabelling shows enhanced sensitivity and the technique is anticipated to contribute greatly to the optimization of immuno-electron microscopy. The potential for greatly accelerated preparation of samples for electron microscopy exists but is yet to be fully realized.

Are alanine aminotransferase, hepatitis B virus DNA or IgM antibody to hepatitis B core antigen serum levels predictors of histological grading in chronic hepatitis B?

Paired sera and liver biopsies from 105 patients with chronic hepatitis B virus infection (34 HBeAg positive and 71 anti-HBe positive) were studied to investigate the relation between the degree of histological activity and alanine aminotransferase (ALT), hepatitis B virus DNA (HBV-DNA) or IgM antibody to hepatitis B core antigen (IgM anti-HBc) levels. ALT levels were significantly higher in patients with piecemeal necrosis (155 +/- 124 vs 75 +/- 42, p = 0.0017), but there were no differences in the ALT values of patients with or without intralobular necrosis. ALT values were within normal range in 29% of 31 patients without versus 15% of 65 with piecemeal necrosis (p = 0.19). Serum HBV-DNA levels were not related to the grade of lobular or portal/periportal activity in HBeAg-positive patients. Anti-HBe-positive subjects with piecemeal necrosis had higher HBV-DNA levels (34 +/- 93 vs 4 +/- 6, p = 0.01). IgM anti-HBc indexes were significantly higher in patients with intralobular necrosis (0.635 +/- 0.600 vs 0.356 +/- 0.367, p = 0.0005) or piecemeal necrosis (0.671 +/- 0.633 vs 0.321 +/- 0.219, p = 0.0002). In summary, since serum IgM anti-HBc-IMx indexes can reflect the grade of histological activity, the quantitative assessment of this antibody could be useful for non-invasive monitoring of hepatocellular damage in chronic hepatitis B.