Clinical impact of monocyte distribution width and neutrophil-to-lymphocyte ratio for distinguishing COVID-19 and influenza from other upper respiratory tract infections: A pilot study

Hui-An Lin; Sheng-Feng Lin; Hui-Wen Chang; Yuarn-Jang Lee; Ray-Jade Chen; Sen-Kuang Hou

doi:10.1371/journal.pone.0241262

Peer Review History

Original SubmissionJune 5, 2020
7 Aug 2020 Decision Letter - Wenbin Tan, Editor PONE-D-20-16913 Clinical Impact of Monocyte Distribution Width (MDW) and Neutrophil to Lymphocyte Ratio (NLR) to Distinguish COVID-19 and Influenza from General Upper Respiratory Tract Infection PLOS ONE Dear Dr. Hou, Thank you for submitting your manuscript to PLOS ONE. After careful consideration, we feel that it has merit but does not fully meet PLOS ONE’s publication criteria as it currently stands. Therefore, we invite you to submit a revised version of the manuscript that addresses the points raised during the review process. Please submit your revised manuscript by Sep 21 2020 11:59PM. If you will need more time than this to complete your revisions, please reply to this message or contact the journal office at plosone@plos.org. When you're ready to submit your revision, log on to https://www.editorialmanager.com/pone/ and select the 'Submissions Needing Revision' folder to locate your manuscript file. 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Upon resubmission, please provide the following: The name of the colleague or the details of the professional service that edited your manuscript A copy of your manuscript showing your changes by either highlighting them or using track changes (uploaded as a supporting information file) A clean copy of the edited manuscript (uploaded as the new manuscript file) 4. Please state the date(s) when you accessed the medical records of the patients included in this study. In addition, please state whether the data was obtained from an electronic database or by paper record review. 5. PLOS requires an ORCID iD for the corresponding author in Editorial Manager on papers submitted after December 6th, 2016. Please ensure that you have an ORCID iD and that it is validated in Editorial Manager. To do this, go to ‘Update my Information’ (in the upper left-hand corner of the main menu), and click on the Fetch/Validate link next to the ORCID field. This will take you to the ORCID site and allow you to create a new iD or authenticate a pre-existing iD in Editorial Manager. Please see the following video for instructions on linking an ORCID iD to your Editorial Manager account: https://www.youtube.com/watch?v=_xcclfuvtxQ Reviewers' comments: Comments to the Author ********** Reviewer #1: I read this timely manuscript with much interest. Even though the small number of COVID-19 patients in this study is the obvious weakness, as pointed out in the Discussion, I appreciate your contribution sharing your clinical insight in this important issue facing frontline healthcare workers and heroes. The following is a list of tasks related to this manuscript for your reference. * page 12: In the paragraph about "Data collection"; please clarify what is MDW in parenthesis. Is it neutrophil to lymphocyte ratio as stated in the sentence? * page 12: In the paragraph about "Statistical method"; there were extra spaces in Pearson's Chi squared test. * page 23: The formatting was not consistent among the three groups in Table 2. * page 24: Is it possible to keep MDW + NLR in the same line for better readability in Table 3? * page 25: This is empty, missing anything here? * It would be a very good idea to include information about the hematology analyzer in this study. This information will help our readers to design future related studies, with monocyte distribution width. Reviewer #2: The present study is highly relevant and novel. However, the small sample size (9 patients confirmed with COVID-19) brings doubt to the significance of the results. The conclusion is not supported by the data due to the extremely small sample size. This study would need to have a much larger sample size to be relevant. Reviewer #3: This paper deals with the cutoff value of monocyte distribution width (MDW) and neutrophil to lymphocyte ratio (NLR), to diagnose patients with COVID-19 and to distinguish them from those with other respiratory infection. The authors have found that the inexpensive biomarkers are easy to use, and they showed that the predictive ability of its discrimination is higher by the combination use. I think that this concept is very interesting, and the diagnosis method is simple and useful because it was challenging for clinical physicians to diagnose patients whether they have COVID-19. However, I have serious concerns over the use of statistics, the sample size of this study, and its cutoff value. I would like to require a major revision of the manuscript before it can be accepted for publication. The authors should fix the problems listed below. Comments: 1. The cutoff value is very tricky because I think that it depends on the sample size. Other reports show the different MDW value in screening for it (Clinica Chimica Acta 509 (2020) 22–24, PLoS ONE 15(1): e0227300[ref 22]). One paper shows that "Reference interval of monocyte distribution width (MDW) in healthy blood donors"(Clinica Chimica Acta 510, (2020) 272-277). Its report shows that RIs obtained by the three calculation methods were about　16-23. On the other hand, the author indicated that "MDW ≥ 20" is a useful value to distinguish COVID-19 from general URI. I think that many healthy donors or patients without COVID-19 are including if we use this cutoff value. I think that more lager number of patients are needed to investigate this study. 2. The authors need to describe the materials and methods in exact detail. What was the ethnicity of patients? Which race was the most common? Which device was used for the analysis of MDW? Which reagent for SARS-CoV-2 RNA detection? The manuscript lacks the corresponding data. These descriptions should be needed. 3. I think that the use of the English language will still require considerable attention. While revising your submission, please upload your figure files to the Preflight Analysis and Conversion Engine (PACE) digital diagnostic tool, https://pacev2.apexcovantage.com/. PACE helps ensure that figures meet PLOS requirements. To use PACE, you must first register as a user. Registration is free. Then, login and navigate to the UPLOAD tab, where you will find detailed instructions on how to use the tool. If you encounter any issues or have any questions when using PACE, please email PLOS at figures@plos.org. Please note that Supporting Information files do not need this step. https://doi.org/10.1371/journal.pone.0241262.r001
Revision 1
17 Sep 2020 Author Response We thank the reviewers for their constructive comments. We have made revisions to the manuscript addressing all the questions and comments raised by the reviewers. The revised text is marked in blue. Our point-by-point responses to comments are as follows: Response to the Academic Editor � As reviewers suggested that the small sample size of COVID-91 (n=9) had compromised the conclusions, which should be fully addressed. The justification of cut-off value also needs to be elaborated � We are grateful for your comments for this manuscript. The limited sample size is the main weakness of our study. No new cases were diagnosed at the Taipei Medical University Hospital after May 1, 2020. According to the data from the Taiwan National Infectious Disease Statistics System, 435 confirmed cases of COVID-19, including 55 indigenous and 380 imported, were reported between March 1, 2020, and April 30, 2020. Thereafter, no indigenous case was reported. Only 41 imported cases were found between May 2, 2020, and July 31, 2020. � The MDW test is not popular in Taiwan at present. Based on our information, the MDW test is only available at two hospitals in Taiwan, including Taipei Medical University Hospital and Chang Gung Memorial Hospital. COVID-19 cases from other hospitals lacked MDW data for our analysis. Therefore, including more cases was a challenge for us. In-depth research with more cases is required in the future. We revised our title nu adding the phrase “a pilot study.”. � In our study, the MDW cutoff was ≥20 for both influenza and COVID-19, which is consistent with studies on septic patients. A recent study showed similar findings. A large cohort study by Ognibene et al. reported that average MDW for the COVID-19 group was 27.3 ± 4.9 (106 negative vs. 41 positive). Although the number of cases in our study is small, the strength of our study is that it uses a combination of two markers, MDW and NLR, in distinguishing COVID-19 from influenza and general URI. Response to Reviewer #1 We thank you for your valuable comments. We have modified in context as following: 1. In the paragraph about "Data collection"; please clarify what is MDW in parenthesis. Is it neutrophil to lymphocyte ratio as stated in the sentence? � This was an error. We have corrected it to monocyte distribution width (MDW). Neutrophil-to-lymphocyte ratio (NLR) and platelet-to-lymphocyte ratio (PLR) have been defined in the next sentence. 2. In the paragraph about "Statistical method"; there were extra spaces in Pearson's Chi squared test. � We have revised this to “Pearson’s chi-square test.” 3. The formatting was not consistent among the three groups in Table 2. � Table 2 has been revised. 4. Is it possible to keep MDW + NLR in the same line for better readability in Table 3? � The typesetting has been adjusted. 5. This is empty, missing anything here? � It is redundant space, and we have removed it. Response to Reviewer #2 The present study is highly relevant and novel. However, the small sample size (9 patients confirmed with COVID-19) brings doubt to the significance of the results. The conclusion is not supported by the data due to the extremely small sample size. This study would need to have a much larger sample size to be relevant. � Thank you very much for appreciating our work. Small sample is a crucial limitation in our research. It was difficult to collect additional samples due to three main reasons. First, no new cases were diagnosed at the Taipei Medical University Hospital after May 1, 2020. This trend was concordant with the small number of cases in Taiwan after April 2020. According to data from Taiwan National Infectious Disease Statistics System, 435 confirmed cases of COVID-19, including 55 indigenous and 380 imported, were reported between March 1 and April 30, 2020. Thereafter, no indigenous case was reported. Only 41 imported cases were found between May 2 and July 31, 2020. Second, the MDW test is not popular in Taiwan at present. Based on our information, the MDW test is only available at two hospitals in Taiwan, including the Taipei Medical University Hospital and Chang Gung Memorial Hospital. COVID-19 cases from other hospitals lacked MDW data for our analysis. Therefore, including more cases was a challenge for us. Response to Reviewer #3 � The cutoff value is very tricky because I think that it depends on the sample size. Other reports show the different MDW value in screening for it (Clinica Chimica Acta 509 (2020) 22–24, PLoS ONE 15(1): e0227300[ref 22]). One paper shows that "Reference interval of monocyte distribution width (MDW) in healthy blood donors"(Clinica Chimica Acta 510, (2020) 272-277). Its report shows that RIs obtained by the three calculation methods were about 16-23. On the other hand, the author indicated that "MDW ≥ 20" is a useful value to distinguish COVID-19 from general URI. I think that many healthy donors or patients without COVID-19 are including if we use this cutoff value. I think that more lager number of patients are needed to investigate this study. � Thank you very much for the constructive comment. We had difficulty in expanding the sample size because of two main reasons. First, no new indigenous case of COVID-19 in Taiwan has been diagnosed since May 2020. Second, the MDW test is only available at two hospitals in Taiwan, including Taipei Medical University Hospital and Chang Gung Memorial Hospital. As no new indigenous cases were found at the two hospitals, new MDW data for COVID-19 patients were not available for our analysis. � We believe that “MDW ≥ 20” is a reasonable cutoff value. This is a crucial clue for clinicians to distinguish COVID-19 from upper URI and influenza in the early stages. In a study by Ognibene et al, the average MDW for the COVID-19 positive group was 27.3 ± 4.9, whereas the average MDW was 20.3 ± 3.3 for the COVID-19 negative group. For the ROC curve analysis, the AUC of MDW (without a cutoff) was 0.91, which was based on a population of 106 negative and 41 positive cases. Moreover, their MDW demonstrated a sensitivity of 98%, specificity of 65%, and cutoff of 20. � The authors need to describe the materials and methods in exact detail. What was the ethnicity of patients? Which race was the most common? Which device was used for the analysis of MDW? Which reagent for SARS-CoV-2 RNA detection? The manuscript lacks the corresponding data. These descriptions should be needed. � We appreciate your valuable suggestion. The indicated information has been added to our revised manuscript. All confirmed patients with COVID-19 and other URIs were ethnically Han Chinese. � MDW was analyzed using the Beckman Coulter UniCel DxH 900 analyzer, a quantitative, multi-parameter, automated hematology analyzer. The WBC differential was established using three measurements: individual cell volume, high-frequency conductivity, and laser-light scatter. Monocytes are identified through this technology and MDW is calculated as the standard deviation of a set of monocyte cell volume values. SARS-CoV-2 RNA was detected through real time PCR using a MagPurix 12S System and a Zinexts MagPurix Viral/Pathogen Acids Extraction Kit B. 3. I think that the use of the English language will still require considerable attention. � Our revised manuscript has been edited for proper English language, grammar, punctuation, spelling, and overall style by a native English-speaking editor. Attachments Attachment Submitted filename: MDWCOVID0911_rebuttal letter_clean.doc https://doi.org/10.1371/journal.pone.0241262.r002
13 Oct 2020 Decision Letter - Wenbin Tan, Editor Clinical impact of monocyte distribution width and neutrophil-to-lymphocyte ratio for distinguishing COVID-19 and influenza from other upper respiratory tract infections: a pilot study PONE-D-20-16913R1 Dear Dr. Hou, We’re pleased to inform you that your manuscript has been judged scientifically suitable for publication and will be formally accepted for publication once it meets all outstanding technical requirements. Within one week, you’ll receive an e-mail detailing the required amendments. When these have been addressed, you’ll receive a formal acceptance letter and your manuscript will be scheduled for publication. An invoice for payment will follow shortly after the formal acceptance. To ensure an efficient process, please log into Editorial Manager at http://www.editorialmanager.com/pone/, click the 'Update My Information' link at the top of the page, and double check that your user information is up-to-date. If you have any billing related questions, please contact our Author Billing department directly at authorbilling@plos.org. If your institution or institutions have a press office, please notify them about your upcoming paper to help maximize its impact. If they’ll be preparing press materials, please inform our press team as soon as possible -- no later than 48 hours after receiving the formal acceptance. Your manuscript will remain under strict press embargo until 2 pm Eastern Time on the date of publication. For more information, please contact onepress@plos.org. Kind regards, Wenbin Tan Academic Editor PLOS ONE Reviewers' comments: Reviewer #1: All comments have been addressed https://doi.org/10.1371/journal.pone.0241262.r003
Formally Accepted
15 Oct 2020 Acceptance Letter - Wenbin Tan, Editor PONE-D-20-16913R1 Clinical impact of monocyte distribution width and neutrophil-to-lymphocyte ratio for distinguishing COVID-19 and influenza from other upper respiratory tract infections: a pilot study Dear Dr. Hou: I'm pleased to inform you that your manuscript has been deemed suitable for publication in PLOS ONE. Congratulations! Your manuscript is now with our production department. If your institution or institutions have a press office, please let them know about your upcoming paper now to help maximize its impact. If they'll be preparing press materials, please inform our press team within the next 48 hours. Your manuscript will remain under strict press embargo until 2 pm Eastern Time on the date of publication. For more information please contact onepress@plos.org. If we can help with anything else, please email us at plosone@plos.org. Thank you for submitting your work to PLOS ONE and supporting open access. Kind regards, PLOS ONE Editorial Office Staff on behalf of Dr. Wenbin Tan Academic Editor PLOS ONE https://doi.org/10.1371/journal.pone.0241262.r004

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