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: 04 Feb 2020  
 
Reviewer: Yueyong Zhu  
 
Reviewer's report:  
 
I am honored to review this manuscript. Systemic inflammation in ACLF has been 
recognized recently, however, the complement system in ACLF has been rarely studied. In 
Qian Li's study, they examined the plasma complement components in ACLF and came to a 
conclusion that classical complement system is activated in the ACLF patients. It is an 
interesting study; however, there are some issues should be addressed.  
 
1. I think the most important result of the research is the C3 activation in plasma in 
ACLF group. Please present this result in the abstract. Apart from the WB figure, please add 
a histogram to show the difference of the expression of C3a, iC3b and C3dg in the results 
section.  
 
2. Line 236 and Line285, the r for C3a and C3 is 4675. The correlation coef ficient 
usually doesn't exceed 1. Please double check the data.  
 
3. I would like to see the relationship between plasma complement components and 
the outcome of patients (survival, infection rate, etc.) rather than the prognosis score.  
 
4. The components in classical pathway are significantly lower in ACLF, but the 
conclusion is the complement system is activated in ACLF. What's your explanation for this 
paradox?  
 
5. Some grammatical errors, for example, line 47 "the complement system is activated 
systemicall y activated", Line 49 -51, "Blood samples from …were enrolled in this survey".  
 
 
 
 
 
 
 
 
 
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.  
 
No 
 
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 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.  
 
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included  on my report to the authors and, if the manuscript is accepted for publication, my 
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I agree to the open peer review policy of the journal