Review for 10.1186/s12876-018-0767-1 (2018)

Reviewer ’s report  
 
Title:  Characterization of the hepatitis B virus DNA detected in urine of chronic hepatitis B 
patients  
 
Version: 0 Date: 25 Jan 2018 
 
Reviewer:  C.-Thomas  Bock  
 
Reviewer’s report:  
 
Dr. Jain and colleagues presented an interesting observational study in which they aimed to 
characterise the appearance of HBV DNA in urine of CHB patients. In a rec ent study the authors 
have shown that HBV DNA could be detected in urine samples of CHB patients; however, I 
didn´t find the journal listed in Medline. New in the presented study is obviously only the 
identification and discrimination of fragmented vs. ful l-length HBV genomes detectable in the 
urine sample. In the presented study the colleagues enrolled 60 CHB patients showing different 
signs of liver disease (hepatitis, cirrhosis, and HCC). Using commercial PCR kits the colleagues 
could show that mainly fr agmented HBV DNA was detectable. However, one sample showed 
potentially full -length genome which was derived from remaining blood in the urine samples of 
this patient. Therefore this result could be excluded. From their findings the authors concluded 
that urine samples from CHB patients with healthy kidney function will not contain "infectious" 
full-length HBV genomes suggesting infectious virions and therefore urine will not be a source 
for HBV infection.  
 
Overall, the manuscript is well written and concis e in its content. The used methods are 
adequate. However, there are some comments which should be addressed.  
 
 
Comments  
 
-  the colleagues concluded that there is no hint that infectious HBV is present in the urine 
samples. As a suggestion, the determination of HBsAg in the urine samples would support this 
statement.  
 
- table 1. There is in the last column shown whether the patient received antiviral treatment or 
not; however, it would be of interest which antiviral the patient received due to renal side effect s 
of some antivirals (e.g., IFN). This could interfere with the detection of HBV DNA in urine.  
 
-  A statically calculation in terms of liver disease progression and identification and number of 
HBV DNA fragments would show in more detail if the number of d etectable fragments is 
affected. What exactly is "hepatitis" in the "liver disease" column?  
 
- Table 2 is not really needed and can be omitted since all data were described in the text giving 
no specific and additional information.  
 
- Fig. 1 the grey bars i ndicating the nucleotide positions are somehow irritating and will give no 
specific information. Therefore the grey bars could be omitted.  
 
Are the methods appropriate and well described?  
If not, please specify what is required in your comments to the authors.  
 
Yes 
 
Does the work include the necessary controls?  
If not, please s pecify which controls are required in your comments to the authors.  
 
Yes 
 
Are the conclusions drawn adequately supported by the data shown?  
If not, please explain in your comments to the authors.  
 
Yes 
 
Are you able to assess any statistics in the manuscript  or would you recommend an 
additional statistical review?  
If an additional statistical review is recommended, please specify what aspects require further 
assessment in your comments to the editors.  
 
I am able to assess the statistics  
 
Quality of written English  
Please indicate the quality of language in the manuscript:  
 
Acceptable  
 
Declaration of competing interests  
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3. Do you hold or are you currently applying for any patents relating to the content of the 
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