Alimentary Pharmacology and Therapeutics Letters to the Editors In conclusion, characterisation of genetic components from S. typhi isolates from chronic carriers and contributions by pattern of the host MHC class II and III genes would be useful to manage high risks associated with chronic carrier stage of S. typhi in different typhoid endemic regions.
ACKNOWLEDGEMENTS The secretarial assistance of Ms Geeta Kaushik is acknowledged gratefully. Declaration of personal and funding interests: None.
Letter: chronic Salmonella typhi carrier status and gall-bladder cancer – authors’ reply V. Nagaraja & G. D. Eslick The Whiteley-Martin Research Centre, Discipline of Surgery, The Sydney Medical School Nepean, Penrith, NSW, Australia. E-mail: [email protected] doi:10.1111/apt.12792
SIRS, We thank Dr Arya and colleagues for their interest in our article1, 2 and highlighting the relationship between HLA and susceptibility to typhoid fever. The momentum for the implementation of personalised medicine in clinical practice is gaining. Recently, HLA genetic screening has been used to prevent carbamazepine-induced toxic effects among persons of Han Chinese descent3 and hypersensitivity to abacavir.4 Similarly, Ivacaftor, an orally available CFTR modulator that is specific for the G551D mutation has come up as a potential treatment for cystic fibrosis,5 thiopurine methyltransferase enzyme activity is predictive of azathioprine related life-threatening myelotoxicity in inflammatory bowel disease6 and reduced-function of CYP2C19 genotype has been related to adverse clinical outcomes among patients treated with clopidogrel.7 Imperial College of Science investigated the association between class II and class III major histocompatibility complex and typhoid fever in Vietnam. It is interesting to see that HLADRB1* 0301/6/8, HLA-DQB1*0201-3 and TNFA*2 (-308)) were associated with susceptibility to typhoid fever and HLA-DRB1*04, HLA-DQB1*0401/2 and TNFA*1 (-308) were linked with disease resistance.8 It would be a good strategy to utilize this characteristic to help prevent typhoid in this cohort of patients, espe1440
REFERENCES 1. Nagaraja V, Eslick GD. Systematic review with meta-analysis: the relationship between chronic Salmonella typhi carrier status and gall-bladder cancer. Aliment Pharmacol Ther 2014; 39: 745–50. 2. Lau SK, Woo PC, Chan CY, Woo WL, Woo GK, Yuen KY. Typhoid fever associated with acute appendicitis caused by an H1- j strain of Salmonella enterica serotype Typhi. J Clin Microbiol 2005; 43: 1470–2. 3. Dunstan SJ, Stephens HA, Blackwell JM, et al. Genes of the class II and class III major histocompatibility complex are associated with typhoid fever in Vietnam. J Infect Dis 2001; 183: 261–8. 4. Celıkbılek M, Selc¸uk H, Yilmaz U. A new risk factor for the development of non-alcoholic fatty liver disease: HLA complex genes. Turk J Gastroenterol 2011; 22: 395–9.
cially in South East Asia. The endemic regions for typhoid can implement more stringent vaccination policies to reduce the health care burden of chronic Salmonella typhi carrier status-related gall-bladder cancer with the help of HLA screening. Another strategy would be to identify the HLA association between chronic Salmonella typhi carriage and gall-bladder cancer. However, whether this will be a cost-effective strategy is a question for the future. We suggest further research in this area to determine this association with the help of genome-wide association studies and animal studies.
ACKNOWLEDGEMENT The authors’ declarations of personal and financial interests are unchanged from those in the original article.2 REFERENCES 1. Arya SC, Agarwal N. Letter: chronic Salmonella typhi carrier status and gall-bladder cancer. Aliment Pharmacol Ther 2014; 39: 1439–40. 2. Nagaraja V, Eslick GD. Systematic review with meta-analysis: the relationship between chronic Salmonella typhi carrier status and gall-bladder cancer. Aliment Pharmacol Ther 2014; 39: 745–50. 3. Chen P, Lin JJ, Lu CS, et al. Carbamazepine-induced toxic effects and HLA-B*1502 screening in Taiwan. N Engl J Med 2011; 364: 1126–33. 4. Mallal S, Phillips E, Carosi G, et al. HLA-B*5701 screening for hypersensitivity to abacavir. N Engl J Med 2008; 358: 568–79. 5. Ramsey BW, Davies J, McElvaney NG, et al. A CFTR potentiator in patients with cystic fibrosis and the G551D mutation. N Engl J Med 2011; 365: 1663–72. 6. Gearry RB, Barclay ML. Azathioprine and 6-mercaptopurine pharmacogenetics and metabolite monitoring in inflammatory bowel disease. J Gastroenterol Hepatol 2005; 20: 1149–57. 7. Mega JL, Simon T, Collet JP, et al. Reduced-function CYP2C19 genotype and risk of adverse clinical outcomes among patients treated with clopidogrel predominantly for PCI: a meta-analysis. JAMA 2010; 304: 1821–30. 8. Dunstan SJ, Stephens HA, Blackwell JM, et al. Genes of the class II and class III major histocompatibility complex are associated with typhoid fever in Vietnam. J Infect Dis 2001; 183: 261–8. Aliment Pharmacol Ther 2014; 39: 1432-1442 ª 2014 John Wiley & Sons Ltd
ACKNOWLEDGEMENTS The secretarial assistance of Ms Geeta Kaushik is acknowledged gratefully. Declaration of personal and funding interests: None.
Letter: chronic Salmonella typhi carrier status and gall-bladder cancer – authors’ reply V. Nagaraja & G. D. Eslick The Whiteley-Martin Research Centre, Discipline of Surgery, The Sydney Medical School Nepean, Penrith, NSW, Australia. E-mail: [email protected] doi:10.1111/apt.12792
SIRS, We thank Dr Arya and colleagues for their interest in our article1, 2 and highlighting the relationship between HLA and susceptibility to typhoid fever. The momentum for the implementation of personalised medicine in clinical practice is gaining. Recently, HLA genetic screening has been used to prevent carbamazepine-induced toxic effects among persons of Han Chinese descent3 and hypersensitivity to abacavir.4 Similarly, Ivacaftor, an orally available CFTR modulator that is specific for the G551D mutation has come up as a potential treatment for cystic fibrosis,5 thiopurine methyltransferase enzyme activity is predictive of azathioprine related life-threatening myelotoxicity in inflammatory bowel disease6 and reduced-function of CYP2C19 genotype has been related to adverse clinical outcomes among patients treated with clopidogrel.7 Imperial College of Science investigated the association between class II and class III major histocompatibility complex and typhoid fever in Vietnam. It is interesting to see that HLADRB1* 0301/6/8, HLA-DQB1*0201-3 and TNFA*2 (-308)) were associated with susceptibility to typhoid fever and HLA-DRB1*04, HLA-DQB1*0401/2 and TNFA*1 (-308) were linked with disease resistance.8 It would be a good strategy to utilize this characteristic to help prevent typhoid in this cohort of patients, espe1440
REFERENCES 1. Nagaraja V, Eslick GD. Systematic review with meta-analysis: the relationship between chronic Salmonella typhi carrier status and gall-bladder cancer. Aliment Pharmacol Ther 2014; 39: 745–50. 2. Lau SK, Woo PC, Chan CY, Woo WL, Woo GK, Yuen KY. Typhoid fever associated with acute appendicitis caused by an H1- j strain of Salmonella enterica serotype Typhi. J Clin Microbiol 2005; 43: 1470–2. 3. Dunstan SJ, Stephens HA, Blackwell JM, et al. Genes of the class II and class III major histocompatibility complex are associated with typhoid fever in Vietnam. J Infect Dis 2001; 183: 261–8. 4. Celıkbılek M, Selc¸uk H, Yilmaz U. A new risk factor for the development of non-alcoholic fatty liver disease: HLA complex genes. Turk J Gastroenterol 2011; 22: 395–9.
cially in South East Asia. The endemic regions for typhoid can implement more stringent vaccination policies to reduce the health care burden of chronic Salmonella typhi carrier status-related gall-bladder cancer with the help of HLA screening. Another strategy would be to identify the HLA association between chronic Salmonella typhi carriage and gall-bladder cancer. However, whether this will be a cost-effective strategy is a question for the future. We suggest further research in this area to determine this association with the help of genome-wide association studies and animal studies.
ACKNOWLEDGEMENT The authors’ declarations of personal and financial interests are unchanged from those in the original article.2 REFERENCES 1. Arya SC, Agarwal N. Letter: chronic Salmonella typhi carrier status and gall-bladder cancer. Aliment Pharmacol Ther 2014; 39: 1439–40. 2. Nagaraja V, Eslick GD. Systematic review with meta-analysis: the relationship between chronic Salmonella typhi carrier status and gall-bladder cancer. Aliment Pharmacol Ther 2014; 39: 745–50. 3. Chen P, Lin JJ, Lu CS, et al. Carbamazepine-induced toxic effects and HLA-B*1502 screening in Taiwan. N Engl J Med 2011; 364: 1126–33. 4. Mallal S, Phillips E, Carosi G, et al. HLA-B*5701 screening for hypersensitivity to abacavir. N Engl J Med 2008; 358: 568–79. 5. Ramsey BW, Davies J, McElvaney NG, et al. A CFTR potentiator in patients with cystic fibrosis and the G551D mutation. N Engl J Med 2011; 365: 1663–72. 6. Gearry RB, Barclay ML. Azathioprine and 6-mercaptopurine pharmacogenetics and metabolite monitoring in inflammatory bowel disease. J Gastroenterol Hepatol 2005; 20: 1149–57. 7. Mega JL, Simon T, Collet JP, et al. Reduced-function CYP2C19 genotype and risk of adverse clinical outcomes among patients treated with clopidogrel predominantly for PCI: a meta-analysis. JAMA 2010; 304: 1821–30. 8. Dunstan SJ, Stephens HA, Blackwell JM, et al. Genes of the class II and class III major histocompatibility complex are associated with typhoid fever in Vietnam. J Infect Dis 2001; 183: 261–8. Aliment Pharmacol Ther 2014; 39: 1432-1442 ª 2014 John Wiley & Sons Ltd
