Review for 10.1186/s12876-020-01258-3 (2020)

Reviewer ’s report  
 
Title: Lower level of complement component C3 and C3a in the plasma means poor outcome 
in the patients with hepatitis B virus related acute -on-chronic liver failure  
 
Version: 1 Date: 21 Feb 2020  
 
Reviewer: Chaoshuang Lin  
 
Reviewer's report:  
 
The manuscript's findings is novel using appropriate method to demonstrate the value of 
C3/3a in prediction of ACLF  prognosis. However, the data provided was not sufficient to 
support the conclusion for the reasons below:  
 
1. The author only found out there was a negative correlation between C3/3a and 
MELD score rather than the real survival rate, as we know, high MELD score just mean the 
high possibility of death.  
 
2. The study only enrolled 27 ACLF patients, I didn't see any data showing how many 
survived and it was not clear whether those survived were liver transplant free or not.  
 
3. In the study, the authors found th ere was no statistical difference in survival and 
non-survival group in terms of C3/3a level, so the conclusion the authors made was 
controversial.  
 
 
Besides the above flaws, the manuscript also needs further polish:  
 
1. The languages used are not accurate, for example, in the abstract, the second row in 
background part there was two "activated", in the discussion part, the second paragraph, "this 
phenomenon may due to" lack "be", the similar mistakes are seen in many parts.  
 
2. Is this study retrospective or prospective? Did it have a clinical trail number?  
 
3. In table 1/2, the p value was comparison between control group and ACLF group? 
Why there was not p value between CHB and ACLF groups?  
 
4. In result C1q, the value was 177001 ng/ml for ACLF group, isn't it  for control 
group, this error was not supposed to exit in the article.  
 
 
 
 
 
 
 
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 no t, please specify 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.  
 
No 
 
Are you able to assess any statistics in the man uscript 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 w ritten English  
Please indicate the quality of language in the manuscript:  
 
Needs some language corrections before being published  
 
 
Declaration of competing interests  
Please complete a declaration of competing interests, considering the following questions:  
 
1. Have you in the past five years received reimbursements, fees, funding, or salary from 
an organisation that may in any way gain or lose financially from the publication of 
this manuscript, either now or in the future?  
 
2. Do you hold any stocks or shares in an organisation that may in any way gain or lose  
financially from the publication of this manuscript, either now or in the future?  
 
3. Do you hold or are you currently applying for any patents relating to the content of 
the manuscript?  
 
4. Have you receiv ed reimbursements, fees, funding, or salary from an organization that 
holds  or has applied for patents relating to the content of the manuscript?  
 
5. Do you have any other financial competing interests?  
 
6. Do you have any non -financial competing interests i n relation to this paper?  
 
 
If you can answer no to all of the above, write 'I declare that I have no competing interests' 
below.  If your reply is yes to any, please give details below.  
 
I declare that I have no competing interests  
 
I agree to the open peer r eview policy of the journal. I understand that my name will be 
included  on my report to the authors and, if the manuscript is accepted for publication, my 
named report  including any attachments I upload will be posted on the website along with the 
authors'  responses. I agree for my report to be made available under an Open Access Creative 
Commons  CC-BY license ( http://creativecommons.org/licenses/by/4.0/ ). I understand that 
any comments  which I do not wish to be included in my named report can be included as 
confidential comments  to the editors, which will not be published.  
 
I agree to the open peer review policy of the journal