Key words : Anti-GSTT1 antibody, GSTT1 genotype, Kidney transplant outcome, Non-HLA antibodies

Introduction

Renal transplantation is the most effective treatment option for chronic end-stage kidney disease. In recent decades, improvements in immunosuppression regimens with more powerful agents have signi-ficantly increased immediate graft survival rates.^1,2 Developments in the prevention and treatment of immunosuppression-related infections have also led to a decline in the incidence and severity of posttransplant infections, increasing the patient’s ability to tolerate more efficient immunosuppression regimens.³

Nevertheless, despite advances in short-term graft survival, long-term survival rates have remained unchanged, and chronic deteriorating graft function still stands as one of the primary causes of graft loss.^2,4 A major cause of chronic graft dysfunction is antibody-mediated rejection (AMR) of donor-specific antigens. Specifically, AMR has been commonly associated with donor-specific HLA antibodies,^5-8 although in recent years there has been an increased interest in the role of non-HLA antibodies in AMR.⁹ Non-HLA antigens have been identified as potential alloantigens in transplantation and are a risk factor for chronic allograft nephropathy.^10-12

Glutathione S-transferase theta 1 (GSTT1) is one type of non-HLA antigen. This enzyme belongs to a superfamily of proteins responsible for catalyzing the conjugation of reduced glutathione to different electrophilic and hydrophobic compounds, which play roles in cellular 5 detoxification and oxidative stress. The GSTT1 enzyme is mostly expressed in the liver and kidneys, with low levels also found in the prostate and small bowel. In the blood, it is only expressed in red blood cells.^13,14 The GSTT1 enzyme is coded by a polymorphic gene with 2 alleles: GSTT1*A (positive) and GSTT1*0 (null). The GSTT1*0 genotype, associated with the total absence of the enzyme, is present in 20% of White populations and 11% to 58% of other ethnic and racial groups.^15-17 Although this enzyme has been proven to have a protective role against free radicals, acting as a significant shield against oxidative stress, there is no evidence to suggest that its absence is linked to chronic renal graft dysfunction.¹⁸ However, GSTT1*0 transplant recipients of GSTT1-positive donors may develop an immune response leading to anti-GSTT1 antibody production, which could in turn cause graft rejection.¹⁹

Most studies on the influence of anti-GSTT1 antibodies have been conducted on liver transplant recipients. These antibodies have been associated with de novo immune hepatitis after liver transplant in GSTT1*0 recipients who were matched with a GSTT1-positive donor.^20-23 Research on the influence of anti-GSTT1 antibodies in renal graft evolution is insufficient. Although it is known that anti-GSTT1 antibodies can develop after kidney transplantation in GSTT1-positive donor/GSTT1*0 recipient matches, their impact on graft outcome is contradictory and inconclusive.^24-27 The high prevalence of GSTT1 positivity in our population increases the likelihood of a GSTT1 mismatch between donor and recipient, which could lead to decreased graft function. The purpose of our study was to analyze the presence of anti-GSTT1 antibodies after renal transplant and their impact on graft outcomes.

Materials and Methods

Study description
We performed an ambispective cohort study of patients who received a kidney transplant between 2009 and 2019. The study considered all patients who underwent transplant during the study period and had a minimum follow-up period of 3 months, with this time spanning up to December 2021.⁶ Renal transplant was performed to ensure ABO blood type compatibility between organ donors and recipients and with no donor-specific anti-HLA antibodies. All donors and recipients were White. The study was approved by the Ethics and Research Committee of the Hospital Universitario de Badajoz.

Genotyping of the GSTT1 allele and detection of anti-GSTT1 antibodies
All recipients were screened for the GSTT1 allele. For GSTT1*0 recipients only, GSTT1 allele genotyping of their donors was performed to determine whether the match was GSTT1-postive donor to GSTT1*0 recipient. In this group, we determined whether anti-GSTT1 antibodies were present in the recipient.

We performed GSTT1 allele detection by real-time polymerase chain reaction (GVS-GSTT1-48; Blackhills Diagnostic Resources) after DNA extraction (MagCore Genomic ADN whole blood kit, Cartridge Code 102, RBC Bioscience) of peripheral blood samples collected in tubes with EDTA anticoagulant. Donor DNA extraction was performed on peripheral blood samples or on isolated lymphatic or splenic cellular specimens. In the GSTT1-positive donor/GSTT1*0 recipient group, we used indirect immunof-luorescence (IIF) and Luminex assays in pretransplant and posttransplant serum samples to establish the presence of anti-GSTT1 antibodies. We performed IIF on triple rodent tissue (liver, kidney, and stomach) (Biocientífica, Menarini Diagnostics) using the automated Zenit UP system (A. Menarini Diagnostics) and Zenit HUB 2.1.³ Rev2n software (A. Menarini Diagnostics). The prepared slides were observed under a LED fluorescence microscope (×100 to ×400 magnification). Specific markers in perivenous hepatocytes (primarily in centrolobular areas) in the liver (Figure 1) and P2 proximal tubules in the kidney (Figure 2) indicated a positive result. For the Luminex assay, we used the LIFECODES non-HLA antibody (Immucor) detection kit.

Clinical and analytical variables
We adjusted for potential confounding variables in our analyses of the effects of anti-GSTT1 antibodies on graft function. We collected the following variables: (1) donor and recipient age; (2) donor biopsy score (a renal biopsy was performed on all donors with expanded criteria [deceased donors aged ≥60 y or aged 50-59 with stroke as the cause of death, history of arterial hypertension, or creatinine >1.5 mg/dl at the time of donation] and on donors after cardiac death); and (3) number of HLA mismatches between donors and recipients in HLA-A, HLA-B, and HLA-DR (0-6). We also collected the type of immunosuppression, which included (1) corticoids, mycophenolate, and delayed dose tacrolimus for donors with brain death without expanded criteria; (2) corticoids, basiliximab, mycophenolate, and delayed dose tacrolimus for donors with expanded criteria and recipients with low immunologic risk; (3) corticoids, basiliximab, mycophenolate, and tacrolimus for donors with expanded criteria and recipients with moderate immunologic risk; and (4) thymoglobulin, corticoids, mycophenolate, and tacrolimus for donors after cardiac death and recipients with high immune compromise. We also collected recipient sex; recipient’s history of diabetes mellitus, ischemic cardiopathy, arterial hypertension, or peripheral vascular disease (intermittent claudication or ischemic stroke); type of dialysis pretransplant (hemodialysis or peritoneal dialysis); recipient’s renal disease etiology; potential presence of delayed graft function (defined as the need for hemodialysis during the immediate posttransplant period); BK virus infection posttransplant; acute rejection; and development of donor-specific anti-HLA antibodies.

The renal graft function was calculated using the CKD-EPI formula, in which plasma creatinine levels were considered at the following time points: 1 year, 2 years, and end of follow-up. Graft loss was defined as the return to chronic dialysis but excluded functioning grafts at the time of recipient’s death.

Statistical analyses
Using the Shapiro-Wilk test, we expressed normally distributed quantitative variables as means and standard deviation (SD) and those that failed the normality test as median and interquartile range (IQR; 25th to 75th percentile). We compared the 2 groups using t tests or Mann-Whitney U test, depending on the case.

We expressed categorical variables as frequency (number of observations) and proportions (percent of the whole or within the category). We compared groups using the Pearson chi-square or the Fisher exact test for 2 × 2 tables, according to the number of expected cases per category, and the likelihood ratio for tables with more than 2 categories.

The impact of anti-GSTT1 antibodies on graft function, as assessed by estimated glomerular filtration rate (eGFR) or graft loss at the end of the follow-up period, was analyzed by multivariable linear or adjusted logistic regression, respectively.

Statistical significance was established at P < .05. We used SPSS 26.0 for Windows for data analyses.

Results

Sample characteristics
Initially, 301 renal transplant patients were considered for this study, 8 of whom were excluded from analysis because of graft loss during follow-up or lack of donor sample availability. The 293 patients included had a median follow-up period of 54.3 months after transplant (Table 1). The mean ± SD age was 54.8 ± 11.8 years, with a greater number of male patients (n = 186, 63.5%) and patients on hemodialysis (n = 238, 81.2%).

The most frequent donation type was donation after brain death (n = 232, 79.2%). More than half of all patients received immunosuppression based on induc-tion with basiliximab and delayed dose tacrolimus, combined with steroids and mycophenolate.

The median eGFR at 1 year, 2 years, and end of follow-up was 51.1 mL/min, 51.1 mL/min, and 47.4 mL/min, respectively. During the follow-up period, 23 patients (7.9%) experienced graft loss and returned to dialysis.

GSTT1 allele genotyping
Of the 293 transplant recipients, 56 (19%) had the GSTT1*0 allele. GSTT1 genotyping of their matched donors was performed in these cases, with 42 donors (75%) having the GSTT1*A allele (GSTT1-positive donor/GSTT1*0 recipient match) and 14 donors (25%) having the GSTT1*0 allele (GSTT1*0 donor/GSTT1*0 recipient match).

Indirect immunofluorescence anti-GSTT1 antibody detection
In the GSTT1-positive donor/GSTT1*0 recipient group, 12 patients (28.6%) screened positive for anti-GSTT1 antibodies. Antibody titer ranged from 1/40 to 1/320, with a median of 1/160. In 4 of these patients (33.3%), antibodies were present at the time of transplant; the median time for detection during follow-up in the remaining patients was 20.8 months (IQR, 4.9-71.2 mo).

Luminex assay anti-GSTT1 antibody detection
Luminex assay results showed that 16 of 42 patients (38.1%) in the GSTT1-positive donor/GSTT1*0 recipient group tested positive for anti-GSTT1 antibodies, with a mean ± SD median fluorescence intensity of 11 700 ± 6360). Among them, 12 patients (75%) were positive at the time of transplant, with median time for detection in the remaining cases of 34.5 months (IQR, 22.0-68.3 mo) posttransplant. A positive anti-GSTT1 antibody IIF screen was corroborated by the Luminex assay in all cases; 37.5% of patients with a positive Luminex assay screen had a history of previous transplant.

The presence of anti-GSTT1 antibodies was also analyzed by both methods in the GSTT1*0/GSTT1*0 group (n = 14), with 1 of the patients testing positive by both techniques. The recipient was a female patients with no previous transplants. She was excluded from the study given that her anti-GSTT1 antibodies were not donor specific (GSTT1*0 donor) and therefore not secondary to the graft.

Effect of anti-GSTT1 antibodies on graft outcome
Table 1 shows the characteristics of patients according to positive or negative anti-GSTT1 antibody screenings as determined by the Luminex assay, which in our study was considered the reference technique due to its higher sensitivity.

Patients with antibodies were younger (mean age of 48.6 vs 55.2 y; P = .030) and had longer dialysis duration before transplant (median of 66.2 vs 40.9 mo; P = .026); there was also a greater percentage with ischemic cardiopathies (31.3% vs 7.3%; P = .007). No statistically significant differences were observed in terms of sex or type of immunosuppression used.

The eGFR at 1 year, 2 years, and end of follow-up was similar between the 2 groups, with no statistically significant differences found, respectively showing 51.2 versus 50.7 mL/min (P = .997), 51.1 versus 49.9 mL/min (P = .842), and 48.2 versus 43.4 mL/min (P = .635). Although the rate of graft loss was higher in the group with positive antibodies, this difference was not statistically significant (18.8% vs 7.3%; P = .122).

The results of the multivariable linear regression analysis did not identify any effects from the presence of anti-GSTT1 antibodies on eGFR at 1 year, 2 years, or end of follow-up, respectively showing β coefficient = 1.4 (95% CI, -8.8 to 11.7; P = .782). β coefficient = 0.9 (95% CI -10.0 to 11.9; P = .866); and β coefficient = -2.6 (95% CI, -13.4 to 8.2; P = .636).

With multivariable logistic regression analysis, we observed no significant relation between a positive test for anti-GSTT1 antibodies and graft loss (odds ratio = 3.5; 95% CI, 0.8-16.0; P = .099).

Discussion

Genetic differences between donors and recipients are one of the main obstacles affecting graft success and outcome. Mismatches in diverse polymorphic antigen systems may lead to an immune response or graft rejection as antibodies develop to target these polymorphic antigens.

With literature documenting histologic cases of AMR in renal transplant biopsies without circulating anti-HLA antibodies, recent research has turned to other types of antibodies as the potential culprits of these findings.⁹

Data from renal transplant recipients who met the histologic criteria for AMR in their renal biopsy and who had no circulating anti-HLA antibodies showed positive findings for anti-GSTT1 antibodies in serum in 16% of cases at the time of biopsy.¹⁹ This finding could be responsible for a higher rate of renal graft loss, as is the case with liver transplant recipients²⁸; however, further studies are necessary to confirm this relation.

Evaluations of the effect of anti-GSTT1 antibodies have found no influence on graft function. Nevertheless, these evaluations had small cohorts and used IIF as the detection method, which is less sensitive than the Luminex assay, both of which factors could have affected the results.^24,27 Other evaluations have shown a relation between the development of anti-GSTT1 antibodies and AMR, although cohort sizes were small and used IIF, thus warranting a cautious interpretation of their conclusions.^25,26 Our study looked into a larger sample of patients and used Luminex assay for antibody detection. We did not observe a connection between the development of anti-GSTT1 antibodies and the renal graft outcome. At the end of follow-up, we observed no significant differences in the eGFR between antibody-positive and -antibody negative patients; although the multivariate analysis showed that the presence of antibodies did increase the risk of graft loss, the difference was not statistically significant.

It is worth noting that all the studies we referenced only described the development of anti-GSTT1 antibodies during follow-up posttransplant. Nevertheless, our study found anti-GSTT1 antibodies at the time of transplant in 75% of patients who would go on to develop an immune response against GSTT1. Some of the patients with pretransplant anti-GSTT1 antibodies had a history of prior transplant, which could have substantiated the existence of antibodies if they were originally GSTT1*0 recipients matched with GSTT1-positive donors at first transplant. Alternatively, the presence of GSTT1 antibodies at the time of transplant could be explained by the blood transfusions, as previously reported.²⁹ The fact that patients with antibodies in our study had been on dialysis longer than their negative counterparts could be consistent with this explanation. Some have suggested that GSTT1*0 women who were pregnant with GSTT1-positive fetuses could ultimately go on to develop antibodies,²⁹ but our study found no significant differences between the sexes. Nonetheless, this could explain the presence of anti-GSTT1 antibodies in our female patient from the GSTT1*0 donor/GSTT1*0 recipient group, who had no history of previous renal transplant.

The studies referenced found no significant differences in terms of chronic graft dysfunction between GSTT1-positive and GSTT1*0 recipients.¹⁸ This enzyme has a role in the elimination of free radicals and provides protection against oxidative stress; therefore, it could play a crucial role in preventing endothelial dysfunction. In our cohort, the rate of ischemic cardiopathies was higher among patients with anti-GSTT1 antibodies. We believe that, rather than being explained by the presence of these antibodies, the finding is likely consistent with the GSTT1*0 condition. The absence of this enzyme would, in turn, deprive the patient of its important protective role against oxidation and endothelial dysfunction, thus increasing the risk for ischemic cardiopathy.^30-32

Another suggestion is that antibody development against this enzyme could lead to a dysfunction in the enzyme itself and eventually to calcineurin inhibitor nephrotoxicity.²⁶ In liver transplant recipients, antibody production is reported to increase when cyclosporine versus tacrolimus is used as immunosuppression.³³ Our study found no statis-tically significant differences in terms of the type of immunosuppression received by the 2 groups; all patients, however, were given both tacrolimus and a calcineurin inhibitor. Nevertheless, the percentage of anti-GSTT1-positive patients was higher in our study than in a previous study that used cyclosporine,²⁴ which could mean that antibody production is unrelated to the calcineurin inhibitor used, but clinical trials would be required to confirm this.

Our study used 2 anti-GSTT1 antibody detection methods, IIF and Luminex assay, whereas most previous studies only used the former. Given the higher sensitivity of Luminex, we were able to detect antibodies in a larger proportion of patients.

The main limitation of our study was the small number of patients with antibodies. Albeit the rate of GSTT1-positive donor/GSTT1*0 matches was similar to that described in literature for our population; in addition, despite the number of patients who went on to develop antibodies being higher than in other studies, the total sample of patients with anti-GSTT1 antibodies was small. Therefore, conclusions should be interpreted with caution. Multicentric and multiracial studies are needed to confirm our findings.

Conclusions

Anti-GSTT1 antibody detection is a frequent discovery among renal transplant patients with the GSTT1*0 (null) allele whose organ came from a donor with a GSTT1*A (positive) allele. The use of Luminex assay for detection is preferrable to IIF given its higher sensitivity. A large number of renal transplant recipients test positive for anti-GSTT1 antibodies at the time of transplant. Development of these antibodies does not affect graft outcome, although further studies are required to confirm these findings.

References:

1. Matas AJ, Smith JM, Skeans MA, et al. OPTN/SRTR 2012 Annual Data Report: kidney. Am J Transplant. 2014;14 Suppl 1(SUPPL. 1):11-44. doi:10.1111/AJT.12579
   CrossRef - PubMed
   
2. Pascual M, Theruvath T, Kawai T, Tolkoff-Rubin N, Cosimi AB. Strategies to improve long-term outcomes after renal transplantation. N Engl J Med. 2002;346(8):580-590. doi:10.1056/NEJMRA011295
   CrossRef - PubMed
   
3. Fishman JA. Infection in solid-organ transplant recipients. N Engl J Med. 2007;357(25):2601- 2614. doi:10.1056/NEJMRA064928
   CrossRef - PubMed
   
4. Meier-Kriesche HU, Schold JD, Kaplan B. Long-term renal allograft survival: have we made significant progress or is it time to rethink our analytic and therapeutic strategies? Am J Transplant. 2004;4(8):1289-1295. doi:10.1111/J.1600-6143.2004.00515.X
   CrossRef - PubMed
   
5. Halloran PF, Schlaut J, Solez K, Srinivasa NS. The significance of the anti-class I response. II. Clinical and pathologic features of renal transplants with anti-class I-like antibody. Transplantation. 1992;53(3):550-555. doi:10.1097/00007890-199203000-00011
   CrossRef - PubMed
   
6. Terasaki PI. Humoral theory of transplantation. Am J Transplant. 2003;3(6):665-673. doi:10.1034/J.1600-6143.2003.00135.X
   CrossRef - PubMed
   
7. Worthington JE, Martin S, Al-Husseini DM, Dyer PA, Johnson RW. Posttransplantation production of donor HLA-specific antibodies as a predictor of renal transplant outcome. Transplantation. 2003;75(7):1034-1040. doi:10.1097/01.TP.0000055833.65192.3B
   CrossRef - PubMed
   
8. Opelz G, Döhler B. Effect of human leukocyte antigen compatibility on kidney graft survival: comparative analysis of two decades. Transplantation. 2007;84(2):137-143. doi:10.1097/01.TP.0000269725.74189.B9
   CrossRef - PubMed
   
9. Filippone EJ, Farber JL. Histologic Antibody-mediated kidney allograft rejection in the absence of donor-specific HLA antibodies. Transplantation. 2021;105(11):e181-e190. doi:10.1097/TP.0000000000003797
   CrossRef - PubMed
   
10. Opelz G. Non-HLA transplantation immunity revealed by lymphocytotoxic antibodies. Lancet. 2005;365(9470):1570-1576. doi:10.1016/S0140-6736(05)66458-6
    CrossRef - PubMed
    
11. Stastny P. Introduction: what we know about antibodies produced by transplant recipients against donor antigens not encoded by HLA genes. Hum Immunol. 2013;74(11):1421-1424. doi:10.1016/J.HUMIMM.2013.05.004
    CrossRef - PubMed
    
12. Sumitran-Holgersson S. Relevance of MICA and other non-HLA antibodies in clinical transplantation. Curr Opin Immunol. 2008;20(5):607-613. doi:10.1016/J.COI.2008.07.005
    CrossRef - PubMed
    
13. Whalen R, Boyer TD. Human glutathione S-transferases. Semin Liver Dis. 1998;18(4):345-358. doi:10.1055/S-2007-1007169
    CrossRef - PubMed
    
14. Juronen E, Tasa G, Uusküla M, Pooga M, Mikelsaar AV. Purification, characterization and tissue distribution of human class theta glutathione S-transferase T1-1. Biochem Mol Biol Int. 1996;39(1):21-29. doi:10.1080/15216549600201021
    CrossRef - PubMed
    
15. Pemble S, Schroeder KR, Spencer SR, et al. Human glutathione S-transferase theta (GSTT1): cDNA cloning and the characterization of a genetic polymorphism. Biochem J. 1994;300(Pt 1):271-276. doi:10.1042/BJ3000271
    CrossRef - PubMed
    
16. Landi S. Mammalian class theta GST and differential susceptibility to carcinogens: a review. Mutat Res. 2000;463(3):247-283. doi:10.1016/S1383-5742(00)00050-8
    CrossRef - PubMed
    
17. Sprenger R, Schlagenhaufer R, Kerb R, et al. Characterization of the glutathione S-transferase GSTT1 deletion: discrimination of all genotypes by polymerase chain reaction indicates a trimodular genotype-phenotype correlation. Pharmacogenetics. 2000;10(6):557-565. doi:10.1097/00008571-200008000-00009
    CrossRef - PubMed
    
18. Pagliuso RG, Abbud-Filho M, Alvarenga MPS, et al. Role of glutathione S-transferase polymorphisms and chronic allograft dysfunction. Transplant Proc. 2008;40(3):743-745. doi:10.1016/j.transproceed.2008.03.008
    CrossRef - PubMed
    
19. Álvarez-Márquez A, Aguilera I, Gentil MA, et al. Donor-specific antibodies against HLA, MICA, and GSTT1 in patients with allograft rejection and C4d deposition in renal biopsies. Transplantation. 2009;87(1):94-99. doi:10.1097/TP.0B013E31818BD790
    CrossRef - PubMed
    
20. Aguilera I, Wichmann I, Sousa JM, et al. Antibodies against glutathione S-transferase T1 (GSTT1) in patients with de novo immune hepatitis following liver transplantation. Clin Exp Immunol. 2001;126(3):535-539. doi:10.1046/J.1365-2249.2001.01682.X
    CrossRef - PubMed
    
21. Aguilera I, Sousa JM, Gavilán F, Bernardos A, Wichmann I, Nuñez-Roldán A. Glutathione S-transferase T1 mismatch constitutes a risk factor for de novo immune hepatitis after liver transplantation. Liver Transpl. 2004;10(9):1166-1172. doi:10.1002/LT.20209
    CrossRef - PubMed
    
22. Rodríguez-Mahou M, Salcedo M, Fernández-Cruz E, et al. Antibodies against glutathione S-transferase T1 (GSTT1) in patients with GSTT1 null genotype as prognostic marker: long-term follow-up after liver transplantation. Transplantation. 2007;83(8):1126-1129. doi:10.1097/01.TP.0000259963.47350.DA
    CrossRef - PubMed
    
23. Salcedo M, Rodríguez-Mahou M, Rodríguez-Sainz C, et al. Risk factors for developing de novo autoimmune hepatitis associated with anti-glutathione S-transferase T1 antibodies after liver transplantation. Liver Transpl. 2009;15(5):530-539. doi:10.1002/LT.21721
    CrossRef - PubMed
    
24. Aguilera I, Wichmann I, Gentil MA, González-Escribano F, Núñez-Roldán A. Alloimmune response against donor glutathione S-transferase T1 antigen in renal transplant recipients. Am J Kidney Dis. 2005;46(2):345-350. doi:10.1053/j.ajkd.2005.04.022
    CrossRef - PubMed
    
25. Aguilera I, Álvarez-Márquez A, Gentil MA, et al. Anti-glutathione S-transferase T1 antibody-mediated rejection in C4d-positive renal allograft recipients. Nephrol Dial Transplant. 2008;23(7):2393-2398. doi:10.1093/ndt/gfm955
    CrossRef - PubMed
    
26. Akgul SU, Oguz FS, Çalişkan Y, et al. The effect of glutathione S-transferase polymorphisms and anti-GSST1 antibodies on allograft functions in recipients of renal transplant. Transplant Proc. 2012;44(6):1679-1684. doi:10.1016/j.transproceed.2012.04.004
    CrossRef - PubMed
    
27. Akgul SU, Oğuz FS, Çalişkan Y, et al. The effect of anti-human leukocyte antigen, anti-major histocompatibility complex class 1 chain-related antigen A, and anti-glutathione transferase-T1 antibodies on the long-term survival of renal allograft. Transplant Proc. 2013;45(3):890-894. doi:10.1016/j.transproceed.2013.02.097
    CrossRef - PubMed
    
28. Ibáñez-Samaniego L, Salcedo M, Vaquero J, Bañares R. De novo autoimmune hepatitis after liver transplantation: a focus on glutathione S-transferase theta 1. Liver Transpl. 2017;23(1):75-85. doi:10.1002/LT.24652
    CrossRef - PubMed
    
29. Wichmann I, Aguilera I, Sousa JM, et al. Antibodies against glutathione S-transferase T1 in nonsolid organ transplanted patients. Transfusion. 2006;46(9):1505-1509. doi:10.1111/J.1537- 2995.2006.00938.X
    CrossRef - PubMed
    
30. Cora T, Tokac M, Acar H, Soylu A, Inan Z. Glutathione S-transferase M1 and T1 genotypes and myocardial infarction. Mol Biol Rep. 2013;40(4):3263-3267. doi:10.1007/S11033-012-2401-6
    CrossRef - PubMed
    
31. Taspinar M, Aydos S, Sakiragaoglu O, et al. Impact of genetic variations of the CYP1A1, GSTT1, and GSTM1 genes on the risk of coronary artery disease. DNA Cell Biol. 2012;31(2):211-218. doi:10.1089/DNA.2011.1252
    CrossRef - PubMed
    
32. Manfredi S, Federici C, Picano E, Botto N, Rizza A, Andreassi MG. GSTM1, GSTT1 and CYP1A1 detoxification gene polymorphisms and susceptibility to smoking-related coronary artery disease: a case-only study. Mutat Res. 2007;621(1-2):106-112. doi:10.1016/J.MRFMMM.2007.02.014
    CrossRef - PubMed
    
33. Aguilera I, Sousa JM, Praena JM, Gómez-Bravo MA, Núñez-Roldan A. Choice of calcineurin inhibitor may influence the development of de novo immune hepatitis associated with anti-GSTT1 antibodies after liver transplantation. Clin Transplant. 2011;25(2):207-212. doi:10.1111/J.1399- 0012.2010.01221.X
    CrossRef - PubMed