Review for 10.1186/1471-230X-12-110 (2012)

Reviewer's report
Title:Primary Biliary Cirrhosis in a genetically homogeneous population: Disease
associations and familial occurence rates.
Version: 2Date:31 March 2012
Reviewer: Eirini Rigopoulou
Reviewer's report:
The study by Mantaka and colleagues tried to elucidate eventual lifestyle and
disease associations as well as familial occurrence rates in a well geographically
defined and homogeneous PBC population from Crete.
This is an interesting study based on the fact, that this is the first study conducted
so a far in a well characterized population of PBC patients from Greece. This
group had the advantage of being homogenous based on the fact that all patients
were of Cretan origin and had Cretan residency. Also important was that both
FDR as well as controls had the same characteristics, concerning origin and
residency.
There are some issues that need to be clarified further:
1) PATIENTS AND METHODS SECTION: The authors should mention in more
detail methods used for determination of AMA (IIFL in which substrate, which
cut-off for AMA positivity), determination of method to detect anti-M2. They also
add details on the method used for the determination ANA.
2) RESULTS SECTION: To describe in more detail characteristics of PBC
population.
How many patients were AMA positive, to explain what it means AMA/M2
positive (IIFL and M2 positive??). In addition the authors should mention how
many patients had PBC- specific ANA and of which type. Detailed histological
data have to be also provided. To refer to progression of disease during follow up
(how many died, how many were transplanted? How many had progression from
stage 1-2 to stage 3-4??)
3) RESULTS SECTION: Table 1: The way smoking history is presented in Table
1 is rather confusing. It is not clear what the percentage in “currently smoking”
represents? This should be clarified.
4) RESULTS SECTION: Table 1: Percentage of patients using nail polish or hair
dye is not significantly different between PBC patients and controls. The present
their data as percentage, while times of exposure per year should be more
accurate especially for hair dye. If the difference between PBC and controls is
not significant, this parameter should not be included in the multivariate analysis
(see page 13).
5) RESULTS SECTION: in accordance to the previous point, the authors should
clarify whether parameters included in the multivariate analysis for female
patients were significantly different between PBC patients and controls. This is
not clear from the results presented.
6) Key references (original and review articles) are missing and must be
included, such as:
Bogdanos DP, Smyk DS, Rigopoulou EI, Mytilinaiou MG, Heneghan MA, Selmi
C, Eric Gershwin M. Twin studies in autoimmune disease:
Genetics, gender and environment. J Autoimmun. 2012 May;38(2-3):J156-69.
Epub 2011 Dec 15.
Bogdanos DP, Baum H, Grasso A, Okamoto M, Butler P, Ma Y, Rigopoulou E,
Montalto P, Davies ET, Burroughs AK, Vergani D. Microbial mimics are major
targets of crossreactivity with human pyruvate dehydrogenase in primary biliary
cirrhosis. J Hepatol. 2004 Jan;40(1):31-9.
Corpechot C, Chrétien Y, Chazouillères O, Poupon R. Demographic, lifestyle,
medical and familial factors associated with primary biliary cirrhosis. J Hepatol.
2010 Jul;53(1):162-9. Epub 2010 Mar 31.
Level of interest: An article whose findings are important to those with closely
related research interests
Quality of written English: Needs some language corrections before being
published
Statistical review: Yes, and I have assessed the statistics in my report.
Declaration of competing interests:
I declare that I have no competing interests