A Combination of Cytological Biomarkers as a Guide in the Diagnosis of Acute Rejection in Lung Transplant Recipients

Round 1

Reviewer 1 Report

 

The manuscript “A new combination of cytological biomarkers as a guide in the diagnosis of acute rejection in lung transplant recipients” by Aguado Ibáñez et al. reports a combination of cellular biomarkers including blood eosinophil counts and lymphocyte counts in BAL to detect acute allograft rejection. The study reports on an important topic, is well composed and reports interesting findings from a comprehensive cohort of 362 lung transplant recipients. Furthermore, the manuscript is well written and the storyline is easy to follow.

While reading the manuscript I identified the following minor concerns:

1.     I know that this combination of biomarkers is already applied in certain transplant centers, thus I suggest to change the title to “A combination of cytological biomarkers as a guide in the diagnosis of acute rejection in lung transplant recipients”.

2.     TBB needs to be introduced in Line 20.

3.     Line 45: The sentence “Furthermore…” needs correction for clarification.

4.     Line 105: The authors likely mean 70 µm instead of 70 mm cell strainer, correct?

5.     Line 130: Please delete “This section may be divided by subheadings. It should provide a concise and precise description of the experimental results, their interpretation, as well as the experimental conclusions that can be drawn.”

6.     Lin 76 the authors state it was 362 patients but in line 133 they write 363. Please correct.

7.     Table 1: The caption Table 1 is doubled. Please delete.

8.     The first part of the discussion is redundant as it is a repetition of the introduction. Please consider shortening.

Author Response

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Reviewer 2 Report

Good job at studying a relevant topic in lung transplantation. I think it is important to clarify that you are looking at "peripheral" blood or haemograms" a term not commonly used in North America. Standardization of BALF technique is important and you describe with some detail but might have missed others like sample handling. You stated following society recommendations based on a document from 1992. I would recommend to review the "ISHLT consensus statement for the standardization of bronchoalveolar lavage in lung transplantation" for a more up to date guideline and compare this to your practice. 

Please clarify under materials and methods what you meant by "variable number of biopsies per patient over time...". I did not read anywhere the median number of biopsies per patient. 

Table 1 and 2 show much more than what is described in the body of the manuscript under results. Recommend to re-arrange paragraphs by grouping togheter statements related to Table 1 and do the same for paragraphs referencing Table 2. 

In Table 2 clarify "concurrent steroid dose according to indication". What do the subcategories describe under it mean? 

In Table 1 it looks like you are using range instead of median and interquartiles when describing Post-transplant (months). Consider changing. 

Great job with Figure 1. 

Delete first paragraph under results.

Under discussion, you mentioned neutrophils in BAL having much more sensitivity and specificity by itself than the proposed combination of peripheral eosinophils and lymphocytes in BAL. Then, it is worth reporting (hopefully the data is available). 

Author Response

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Reviewer 3 Report

The potential role of EOS in lung transplant is intriguing and several studies investigated the issues, nevertheless little is known of these cells in acute rejection and other complications following lung transplant. The paper tries to better characterize the potential role of EOS as clinical biomarkers of ACR diagnosis in conjunction with BAL lymphocytes.

 

Specific issues:

 

The paper does not add great novelty to that previous published by the same authors. They confirmed their observations and only added a new stratification by the number of lymphocytes in BAL. These results are generated in the same cohort, confirmation is not surprising. This represents the main bias of the study. 

Implication of EOS in this particular setting and their role in combination with BAL cellular findings might deserve a validation cohort.

 

Number of patients in the abstract, methods and results are different (362 vs 363).

 

How was EOS cutoff of 200 determined? A ROC curve should be used to identify the best cutoff.

 

Peripheral blood and BAL findings do not correlate regarding EOS counts. The authors should try to speculate on this, why aren’t eos present at alveolar levels if increased in the blood?

 

Different grades of EOS infiltration can be observed at pathology during ACR. It should be of great interest to correlate blood and BALF findings with pathology, not limiting to a rough classification in the presence and absence of ACR and its grades.

 

As discussed by the authors, the histological diagnosis of ACR is not easy and different degrees of concordance among pathologists have been reported in the literature.

In the present study pathology was assessed by only one pathologist.

 

It is not clear if patients with AMR were included among ACRs. In AMR, pathology can somehow be superimposed to ACR. 

 

The role of EOS as prognostic marker has not been considered. It should be of great interest to study how the presence of EOS might identify patients requiring more aggressive treatments or predicting ACR recurrence. 

 

Author Response

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Round 2

Reviewer 3 Report

I have no further comments. However, I was unable to track changes in the manuscript regarding points 3, 4, 7, 8 of my previous revision.

Author Response

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