Review for 10.1186/s12876-021-01905-3 (2021)

Reviewer’s report
Title: 
SARS-CoV-2 identified by transmission electron microscopy in
lymphoproliferative and ischemic intestinal lesions of COVID-19 patients with
acute abdominal pain: two case reports
Version: 
0 
Date: 
28 Feb 2021
Reviewer's report:
Dear Authors, 
this study included two cases of confirmed COVID-19 infection and 
also
documented by TEM (electron microscopy) with silent 6 moths of latent
infection. 
Both cases were surgically operated and the viral particles were shown
by TEM from the tissues of the patients especially in the endothelial cells
supporting the vascular pathophysiology of the COVID-19 infection. 
Although the number of patients were very small, the cases were well
documented with their medical history, laboratory, imaging studies, surgery and
pathological specimens beside TEM documentation. On the other side as the
authors themselves accepted there were some limitations such as the lack of
SARS-CoV2 assessment in the stools of the patients at admission and during the
follow-up and also the lack of other morphological and complementary in-situ
techniques demonstrating viral components in the intestine. Still TEM was able
to demonstrate assembled virions in COVID-19 infected patients. 
Still I have two more suggestions to progress;
For the first case who was eventually diagnosed as diffuse large B-cell
lymphoma (DLBCL), the patient underwent clinical recovery, disappearance of
fever, frank reduction of the 
abdominal mass, blood test normalization and
pulmonary infiltrate improvement with the pharmacological treatment for
COVID-19 were instituted with hydroxychloroquine 200mg/12h orally (PO),
ceftriaxone 1g/24h intravenous (IV), azithromycin 500mg/24h PO and
Lopinavir/Ritonavir 400mg/100mg/12h PO. Here I think it is important to
indicate that the treatment was not containing any corticostreoid agent. Because
corticosteroids are very commonly used in the treatment of COVID-19 cytokine
storm and also effective in lymphoma. In the discussion section authors should
state that the patient did not received any corticosteroid treatment hence the
positive clinical response was not related to steroids' healing effect on
lymphoma.
For the gastrointestinal involvement rate and severity of COVID-19 infection in
patients with gastrointestinal involvement, a recent meta analysis with more then
68.000 patients should have been addressed 'Newly Reported Studies on the
Increase in Gastrointestinal Symptom Prevalence withCOVID-19 Infection: A
Comprehensive Systematic Review and Meta-Analysis'. 
After addition of these two suggestions I would like to consider an 'accept' option
for the manuscript. 
Thank you
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Is the study design appropriate to answer the research question (including the use
of appropriate controls), and are the conclusions supported by the evidence
presented?
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Are the images in this manuscript (including electrophoretic gels and blots) free
from apparent manipulation?
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