Example of letter to editor
……………………………………………
…………………………………………….
Faculty of Medicine, Khon Kaen University
Khon Kaen 40002, Thailand
Tel / Fax 66-43-……………………….
Email: …………………………………………..
25 July 2009
Simon D. Shorvon,
Institute of Neurology, University College London
London, WC1N 3BG, United Kingdom
Subject : Manuscript submission
Dear Prof. Shorvon,
I would like to submit the manuscript entitled " Relationship between HLA-
B*1502 and carbamazepine–induced severe cutaneous adverse reactions in a Thai population". The issue of ethnicity has recently been raised for the association between
CBZ-induced SJS/TEN and HLA-B*1502 in which the strong association was found only in Han Chinese but not in Japanese and Caucasian populations. To our knowledge, our data reported herein is the first large cohort study in other Asian ethnic that demonstrated the strong association between CBZ-induced SJS/TEN and HLA-B*1502 .
The sensitivity and specificity of HLA-B*1502 for predicting SJS/TEN caused by CBZ found in the preset study was very high which suggests that the HLA-B*1502 is a useful pharmacogenetic marker to identify Thai individuals who may at risk for these potentially life-threatening cutaneous reactions.
I warrant that this manuscript has been read by all co-authors and I have submitted this manuscript on behalf of all the authors with their full consent. The authors declare no conflicts of interest. I would be very appreciated if you could consider our manuscript for publication in your journal.
Sincerely Yours,
(Dr……………………………………………………….)

Letter from the Editor after submission
From: epilepsia@epilepsia.com
PASS WORD wichittra123
To: ……………………………………………………………
CC:
Subject: Epilepsia - Manuscript EPI-00539-2009.R1
Body: Dear Dr. …………………………………………………:
This is a computer generated message.
Thank you very much for submitting your revised manuscript to Epilepsia.
Your manuscript entitled, Association between HLA-B*1502 and carbamazepine–induced severe cutaneous adverse drug reactions in a Thai population has been successfully uploaded to Manuscript Central.
Please make note of your manuscript number: EPI-00539-2009.R1. We will direct all future communications to you, the corresponding author, via e-mail.
We attempt to complete the review process as fast as possible, and
Epilepsia is making strenuous efforts to ensure as short a turn-around time as is compatible with a high quality peer review process. Manuscript processing is entirely dependent on the timeliness of our reviewer feedback. It typically takes one week to assign reviewers and another 2-3 weeks to obtain reviews. If a reviewer does not return his/her comments within four weeks, another reviewer may be invited. Reminders are sent to tardy reviewers, but I’m sure you can understand that the requested deadline cannot be enforced.
Revised manuscripts are sent to the original reviewers unless the revisions are minor, in which case the Editor will usually make a final decision on the manuscript him/herself.
Date Sent: 16-Sep-2009

Example of comment from Editor
06-Sep-2009
EPI-00539-2009
Association between HLA-B*1502 and carbamazepine–induced severe cutaneous adverse reactions in a Thai population
Dear Dr. ……………………………………………………………………………….:
Your manuscript has been reviewed, and our reviewers have indicated that the paper should be considered for publication only with significant revisions. The reviewers found merit in your paper but also expressed significant concerns (see comments below). In particular, one reviewer suggested that the manuscript be shortened to the
Brief Communication format and we agree with this suggestion. If you can satisfactorily address these concerns, we will again consider the manuscript. Please understand that publication after revision is not guaranteed. A decision on acceptance will be made only after your revised manuscript has been re-reviewed.
Thank you for your interest in publishing your work in Epilepsia, and for submitting your manuscript to this journal. We look forward to receiving your revised paper.
Sincerely,
Renzo Guerrini, Editor
________________________________________
Reviewers' Comments to Author (if applicable):
Reviewer: 1
Comments to the authors
This article shows that HLA-B*1502 is as strongly associated with CBZ-induced
SJS/TEN in Thai population as in Han Chinese population. Since relationships between idiosyncratic adverse reaction and HLA-type are dependent on ethnicity, the result of this large scale case-control study on SJS/TEN in Thai population is worth publishing with minor revision.
Minor comments
1. Table 2
The SBT of No.2 patient may be read “1502/3909” instead of “502/3909”.
2. The authors performed not a cohort study but a case-control study.
3. Grammatical errors in Discussion part
Line 15, p13: Who did not carried HLA-B*1502
Line 30, p14: who may at risk for these …

Reviewer: 2
Comments to the authors
Comments:
1.This study is primarily verifying the genetic association information in a different population, and lacks of novelty/investigation. As the absence of impact to this field, revision to Brief Communication is suggested.
2.The title needs revision.
3.The authors described two methods for determining HLA-B genotype, i.e., sequencespecific primers for real-time PCR (a commercial kit) and sequence-based typing
(SBT). The information for the commercial kit was not clear in the manuscript, and the authors should provide more detailed information regarding the kit, such as reference paper, oligonucleotide sequence, discrimination of the ~1000 known HLA-B alleles, false positive rate, false negative rate, sensitivity/specificity of the kit. By comparison,
SBT is a well established method, and it could offer clear and accurate HLA genotype data. These two methods are redundant, in which the commercial kit could not provide genotype data, thus it is not so relevant in this study.
4.The authors did not clearly describe the ethnic genetic background of their study subjects. In the method, the patients were described to be native Thais or Thai-Chinese, however, the results part reported the patients were native Thai. A clear assessment of the genetic background is very important for a genetic association study. It is important to see whether the association is only replicated in Chinese, or in both the Thais, and
Chinese.
5.The genetic background of enrolled study subjects will influence how to choose a suitable reference population for studying the allele frequency association. The ethnic genetic background of the enrolled subjects should be further stratified.
6.The HLA-B*1502 allele/phenotype frequency data of different populations provided in the manuscript is inconsistent, incorrect and confusing.
7.The authors enrolled a large cohort of carbamazepine-SJS patients. It is a pity they did not provide the incidence data of this disease.
8.The authors mentioned 27 patients received concomitant drugs in addition to carbamazepine. They did not provide supportive, assessable method for determining carbamazepine being the most likely culprit drug.
9.The table 2 is out of order.

10.The table 3 provides association information between HLA-B alleles and CBZ-SJS.
It is incomplete.
11.There were many typos and the manuscript needs English editing. For example, the method section of SBT is “sequence-based”, not “sequence base”.

Example of response to editor after received the comment from reviwers
………………………………………
……………………………………..
Faculty of Medicine, Khon Kaen University
Khon Kaen 40002, Thailand
Tel / Fax……………………………………….
Email: …………………………….
16 September 2009
The Editor,
Epilepsia,
Subject : Manuscript resubmission
Dear The Editor,
Thank you very much for accepting our manuscript (EPI-00539-2009) to be published in your journal. We have revised our manuscript according to the reviewers’comments. We have also shorten our manuscript to the Brief Communication format as you suggestion. One of the reviewer suggested us to change the title of our manuscript so we decide to change from “Relationship between
HLA-B*1502 and carbamazepine–induced severe cutaneous adverse reactions in a Thai population” to
“Association between HLA-B*1502 and carbamazepine–induced severe cutaneous adverse drug reactions in a Thai population”. We also response to all comments from reviewers point by point.
We would be very appreciated if you could consider our manuscript to be published in your journal.
Sincerely Yours,
(Dr……………………………………..)

Response to Reviewers’comments
Reviewer: 1
Comments to the authors
This article shows that HLA-B*1502 is as strongly associated with CBZ-induced
SJS/TEN in Thai population as in Han Chinese population. Since relationships between idiosyncratic adverse reaction and HLA-type are dependent on ethnicity, the result of this large scale case-control study on SJS/TEN in Thai population is worth publishing with minor revision.
Minor comments
1. Table 2
The SBT of No.2 patient may be read “1502/3909” instead of “502/3909”.
2. The authors performed not a cohort study but a case-control study.
3. Grammatical errors in Discussion part
Line 15, p13: Who did not carried HLA-B*1502
Line 30, p14: who may at risk for these …
Response: Thank you very much for suggestions and point out some typing errors in the manuscript. We have corrected those typing errors already.
Reviewer: 2
Comments to the authors
Comments:
1. This study is primarily verifying the genetic association information in a different population, and lacks of novelty/investigation. As the absence of impact to this field, revision to Brief Communication is suggested.
Response: The issue of ethnicity has been raised for the association between CBZinduced SJS/TEN and HLA-B*1502 since the strong association was found only in Han
Chinese but not in Japanese and Caucasian populations. The US-FDA has recently released a warning to health professionals and patients that these severe cutaneous adverse drug reactions (SCADR) may occur in patients with HLA-B*1502 and has also

recommended genetic screening for patients of Asian ancestry prior to initiation of
CBZ therapy. Whether HLA-B*1502 is a valid pharmacogenetic test for CBZ-induced
SJS/TEN in all Asian populations need to be further investigated.
The present study is the first large scale case-control study in Asian ethnic that has high frequency of HLA-B*1502 other than Han Chinese. The strong association between this HLA-B allele and CBZ-induced SJS/TEN suggests that an application of
HLA-B*1502 genotyping as a screening tool before prescribing CBZ will help to prevent CBZ-induced SJS/TEN in Thailand as well as other Southeast Asian countries which have high prevalence of these SCADR.
As the reviewer and the Editor suggest that our manuscript should be revised to
Brief Communication, we t have to rewrote several parts in the manuscript to suit to the format of Brief Communication.
2. The title needs revision.
Response: We revised the title from “Relationship between HLA-B*1502 and carbamazepine–induced severe cutaneous adverse reactions in a Thai population” to
“Association between
HLA-B*1502 and carbamazepine–induced severe cutaneous adverse drug reactions in a Thai population”
3. The authors described two methods for determining HLA-B genotype, i.e., sequencespecific primers for real-time PCR (a commercial kit) and sequence-based typing
(SBT). The information for the commercial kit was not clear in the manuscript, and the authors should provide more detailed information regarding the kit, such as reference paper, oligonucleotide sequence, discrimination of the ~1000 known HLA-B alleles, false positive rate, false negative rate, sensitivity/specificity of the kit. By comparison,
SBT is a well established method, and it could offer clear and accurate HLA genotype data. These two methods are redundant, in which the commercial kit could not provide genotype data, thus it is not so relevant in this study.
Response: The standard method for determination of HLA-B genotypes is sequence-based typing (SBT). However, this method is impractical in the clinical setting because the excess cost of the system, reagents and software analysis as well as

long term turn around time. The simple HLA-B*1502 test may open the door for clinical applications of HLA-B*1502 to prevent CBZ-induced SJS/TEN. In the present study, we determined the presence of HLA-B*1502 in subjects by using PG1502 DNA detection kit because we want to evaluate the clinical utility of this test kit compared to the SBT method. This test kit was approved by Taiwan’s Department of Health as an in vitro diagnostic (IVD).
Because this kit is a commercial kit and the manufacturer could not share the detail of the oligonucleotide sequences that used in their kit with us. However, we add some detail of this kit such as sensitivity and specificity in the method part (page 6) as :
“ HLA-B*1502 genotyping
Analysis for the presence of the HLA-B*1502 allele was performed using a
PG1502 DNA detection kit (Pharm i Gene, Inc., Taipei, Taiwan) that was approved by
Taiwan’s Department of Health as an in vitro diagnostic (IVD). The kits are real-time
PCR-based with sequencing specific primers directed toward HLA-B*1502 and the internal control gene. The sensitivity and specificity of this kit for detection of the
HLA-B*1502 allele claimed by the manufacture are ~99% and >95% , respectively.”
As the Editor suggested that our manuscript should be revised to Brief
Communication, we therefore have to shorten the material part in the manuscript.
The false positive and false negative of the test also mentioned in the
Discussion part (page 10, 1st paragraph) as
“According to manufacturer’s experience, however, this test may give false positive results for individuals who carry HLA-B*1513 . Although the HLA-B*1513 was not detected in our patients, its allelic frequency in a general Thai population is about

1.5% (dbMHC database; http://www. ncbi.nlm.nih.gov/projects/gv/mhc/ihwg.cgi).
Therefore, using this kit in a population with a high frequency of HLA-B*1513 may exclude some patients who may not be at risk of CBZ-induced SJS/TEN.”
4. The authors did not clearly describe the ethnic genetic background of their study subjects. In the method, the patients were described to be native Thais or Thai-Chinese, however, the results part reported the patients were native Thai. A clear assessment of the genetic background is very important for a genetic association study. It is important to see whether the association is only replicated in Chinese, or in both the Thais, and
Chinese.
Response: Thank you very much for valuable suggestions. All of our patients in cases and controls were native Thais. We interviewed all subjects about their ancestry to make sure whether they are native Thais or not. We agree with the reviewer’s opinion that a clear assessment of the genetic background is very important for a genetic association study and it is important to see whether the association is in our native
Thais or not.
We therefore revise the last paragraph in the Study population section (page 6) to
“All case and control patients were interviewed by investigators about the history of their biological parents and grandparents and they were classified as native
Thai because both of their biological parents and grandparents were born in Thailand.
Subjects were informed both verbally and in writing about the experimental procedures and the purpose of the study. The study protocol was approved by the institutional review boards.”

5. The genetic background of enrolled study subjects will influence how to choose a suitable reference population for studying the allele frequency association. The ethnic genetic background of the enrolled subjects should be further stratified.
Response: All of our cases and controls were native Thais and recruited from the same hospitals. In our opinion, we think it is not necessary to further stratified tthem.
6. The HLA-B*1502 allele/phenotype frequency data of different populations provided in the manuscript is inconsistent, incorrect and confusing.
Response: Thank you so your comments. We did correct for the confusing data already. Since there are two different types of frequency, allelic frequency and phenotype frequency that we used in our previous version, we decided to mention only the allelic frequency of HLA-B*1502 in this revised version.
We change from “The frequency subjects who carried
HLA-B*1502 (phenotype frequency) observed in the CBZ-tolerant controls (11.90%) was quite similar to that reported in the general Thai population (12.12%) (data from dbMHC data base; http://www.ncbi.nlm.nih.gov/projects/gv/mhc/ihwg. cgi).” The 3rd paragraph, page 12 of the original version
To
“In the present study, the HLA-B*1502 allele was found in 37 out of 42 CBZinduced SJS/TEN patients (88.10%) as compared to 5 out of 42 (11.90%) CBZ-tolerant controls. The 6.0% allelic frequency of HLA-B*1502 observed in the CBZ-tolerant control group was quite similar to the 6.1% that was reported in the general Thai population (dbMHC database; http://www.ncbi.nlm.nih.gov/projects/gv/mhc/ihwg.cgi).
(2nd paragraph, page 9 of this revised manuscript )
7. The authors enrolled a large cohort of carbamazepine-SJS patients. It is a pity they did not provide the incidence data of this disease.
Response: Most of our SJS/TEN cases were the patients who admitted in our hospital (Srinagarind Hospital) which is the tertiary care hospital and almost all of the

cases were referred from other city hospitals nearby. So we could not estimate the incidence of CBZ-induced SJS because we did not have the actual number of patients who have been prescribed CBZ in those hospitals. However, the incidence of CBZinduced SJS/TEN has been previously reported by Locharernkul et al., 2008 in
Epilepsia and we did mention this incidence in our e result part (page 8) as “Thus, by assuming the prevalence of CBZ-induced SJS/TEN in a Thai population as 0.27% as previously reported (Locharernkul et al., 2008), the PPV and NPV of the HLA-B*1502 were 1.92% and 99.96%.
8. The authors mentioned 27 patients received concomitant drugs in addition to carbamazepine. They did not provide supportive, assessable method for determining carbamazepine being the most likely culprit drug.
Response: We mentioned in the first paragraph of the methods and material section that “In all enrolled cases, CBZ would be identified as the culprit drug for SJS or TEN if the symptoms occurred within the first 3 months of CBZ exposure and the symptoms resolved upon withdrawal of this drug” and also mentioned in the 2nd paragraph of the result part that “Thirteen patients received only CBZ while 27 patients received concomitant drugs. However, there were no apparent cutaneous adverse reactions when these medications were not concomitantly taken with CBZ.”
9. The table 2 is out of order.
Response: We have corrected it already.
10.The table 3 provides association information between HLA-B alleles and CBZ-SJS.
It is incomplete.
Response: We have revised Table 3 according to the reviewer’s comment by selecting some alleles that presented in > 2 patients either in case or control group. We think it is not necessary to show all alleles in this table. The title of the Table also changed from
“Frequencies of individual
HLA-B allele in patients with CBZ-induced SJS/TEN and

CBZ-tolerant patients” to “Frequencies of certain HLA-B allele in patients with CBZinduced SJS/TEN and CBZ-tolerant patients.”
11. There were many typos and the manuscript needs English editing. For example, the method section of SBT is “sequence-based”, not “sequence base”.
Response: We have revised carefully checked for typos and also ask Prof. James Wills who is an Emeritus Professor at University of Wisconsin-Madison , USA for English editing of the manuscript for us.