Dear Editor,

We found that erythrocyte glutathione transferase, an enzyme devoted to the body detoxification from endogenous and exogenous toxins, is overexpressed in humans in case of increased blood toxicity as it occurs in kidney dysfunctions and environmental pollution [1–3]. In a recent paper, we also reported that erythrocyte glutathione transferase (e-GST) may be an early biomarker for kidney dysfunction in diabetic patients [4]. More precisely, we found that a statistically significant increase in e-GST activity is present in diabetic patients even in the absence of an increase in traditional biomarkers of kidney damage i.e., albuminuria [4]. Evidence was also given that the observed increase is not caused by diabetes per se. The hypothesis that e-GST may indicate an incipient defect in the kidney functionality is a fascinating idea that must be corroborated by further investigations and epidemiologic studies. In this context, we explored the possibility that e-GST hyperexpression could correlate with some of the many biomarkers usually tested in diabetic diseases. In Table 1 are summarized the possible correlation of some clinical parameters between the different groups (healthy subjects, diabetic non-nephropatic patients, and diabetic nephropatic patients). Table 2 shows that no evident correlation is present among e-GST and some clinical parameters. The absence of correlation confirms that e-GST must be considered a novel biomarker which reveals an incipient kidney defective function in case of diabetic disease. The early increase in the e-GST activity in diabetic patients without any apparent signal of renal damage can be explained by assuming an elevation of the circulating toxins and not as a consequence the modification of other classical parameters. Recently, e-GST, present in the erythrocytes and easily measured, has disclosed new possible use as biomarker of kidney status in transplanted patients that will be object of future investigations.

Table 1 Correlation of clinical parameters among the control group, the diabetic non-nephropatic patients, and the nephropatic patients
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Table 2 Correlations between e-GST values and some clinical parameters
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