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| Year : 2020 | Volume
: 31
| Issue : 5 | Page : 1154-1155 |
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| Thiopurine S-methyltransferase Genetic Polymorphism and Its Contribution for Azathioprine-Induced Myelosuppression in Kidney Transplant Recipients: A Summative Analysis |
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Pathum Sookaromdee1, Viroj Wiwanitkit2
1 Private Academic Consultant, Bangkok, Thailand
2 Department of Community Medicine, Dr. D. Y. Patil University, Pune, Maharashtra, India
Click here for correspondence address and email
| Date of Web Publication | 21-Nov-2020 |
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How to cite this article:
Sookaromdee P, Wiwanitkit V. Thiopurine S-methyltransferase Genetic Polymorphism and Its Contribution for Azathioprine-Induced Myelosuppression in Kidney Transplant Recipients: A Summative Analysis. Saudi J Kidney Dis Transpl 2020;31:1154-5 |
How to cite this URL:
Sookaromdee P, Wiwanitkit V. Thiopurine S-methyltransferase Genetic Polymorphism and Its Contribution for Azathioprine-Induced Myelosuppression in Kidney Transplant Recipients: A Summative Analysis. Saudi J Kidney Dis Transpl [serial online] 2020 [cited 2023 Feb 4];31:1154-5. Available from: https://www.sjkdt.org/text.asp?2020/31/5/1154/301189 |
To the Editor,
Azathioprine is an immunosuppressant that is generally used after renal transplantation.[1] The possible important adverse effect of azathioprine is myelosuppression. In a recent report from Thailand, the rate of myelosuppression of this drug among renal recipients is equal to 7%.[2] To detoxify this drug, the main required enzyme is thiopurine S-methyltransferase (TPMT). The TPMT is a polymorphic enzyme with many polymorphisms. The effect of TPMT polymorphism on azathioprine-induced myelosuppression in kidney transplant recipients is mentioned in the literature.[3],[4] Here, the author performed a summative analysis to assess the interrelationship between TPMT polymorphism and its contribution for azathioprine-induced myelosuppression in kidney transplant recipients in Thailand, a tropical country in Indochina.
The clinical mathematical model technique is used for the present reappraisal study. The primary data on the TPMT polymorphism frequency distribution[5] and the risk due to different TPMT polymorphisms for azathioprine-induced myelosuppression in kidney transplant recipients in Thailand[2] are used for further modeling calculation. Based on the available primary data, it has been found that the frequency of homozygous wild type of TPMT is equal to 90.5%[3] and the odds ratio for having mutated type comparing to wild type of TPMT is equal to 14.18.[2] First, the odds probability calculation is done in order to transform the odds to risk probability. For homozygous wild type (odds = 1), the transformed probability will be equal to 50%. For non-homozygous wild type, the transformed probability will be equal to 93.41%. Comparing the derived probability rates between non-homozygous wild type and homozygous wild type, the rate of non-homozygous wild type is 1.87 times higher.
To estimate the contributing chance due to different polymorphisms of TPMT, the path probability distribution calculation is done as presented in [Table 1]. Based on the analysis, the chance that a homozygous wild type contributes to azathioprine-induced myelosuppression in kidney transplant recipients is more than that of non-homozygous wild type. This is explainable by a more common frequency of homozygous wild type in general renal recipients. Therefore, close monitoring for possible azathioprine-induced myelosuppression in kidney transplant recipients in patients receiving azathioprine is necessary regardless of TPMT polymorphism determination. | Table 1: Path probability distribution due to different polymorphisms of thiopurine S-methyltransferase.
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Conflict of interest: None declared.
 References | |  |
| 1. | Ahmed AR, Moy R. Azathioprine. Int J Dermatol 1981;20:461-7.  |
| 2. | Vannaprasaht S, Angsuthum S, Avihingsanon Y, et al. Impact of the heterozygous TPMT*1/ *3C genotype on azathioprine-induced myelosuppression in kidney transplant recipients in Thailand. Clin Ther 2009;31: 1524-33. |
| 3. | Cabaleiro T, Roman M, Gisbert JP, Abad-Santos F. Utility of assessing thiopurine S-methyltransferase polymorphisms before azathioprine therapy. Curr Drug Metab 2012;13: 1277-93. |
| 4. | Guillotin V, Galli G, Viallard JF. Usefulness of thiopurine methyltransferase polymorphism study and metabolites measurement for patients treated by azathioprine. Rev Med Interne 2018;39:421-6. |
| 5. | Srimartpirom S, Tassaneeyakul W, Kukongviriyapan V, Tassaneeyakul W. Thiopurine S-methyltransferase genetic polymorphism in the Thai population. Br J Clin Pharmacol 2004;58:66-70. |
Correspondence Address:
Pathum Sookaromdee
Private Academic Consultant, Bangkok
Thailand
 Source of Support: None, Conflict of Interest: None  | Check |
DOI: 10.4103/1319-2442.301189
[Table 1] |
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