The relationship of transforming growth factor-β1 gene polymorphism, its plasma level, and gingival overgrowth in renal transplant recipients receiving different immunosuppressive regimens

Background: Cyclosporin A (CsA) induces gingival overgrowth (GO) in patients who seem to be prone to this disorder. It is still impossible to determine which patients will develop GO. Patients treated with the new immunosuppressive drug tacrolimus seem not to have GO. The aims of this study were to investigate transforming growth factor-beta 1 (TGF-beta 1) gene polymorphisms in renal transplant recipients treated with CsA or tacrolimus and to establish an association between these polymorphisms and TGF-beta 1 plasma concentration and the incidence of GO. Methods: The examined group consisted of 134 renal transplant recipients. Ninety-two underwent CsA treatment (50 with and 42 without GO), and 42 underwent tacrolimus treatment. Age, gender, time after transplantation, calcineurin inhibitor total dosage, number of teeth, and sulcus bleeding index were analyzed. TGF-beta 1 plasma levels were estimated in 60 CsA- and 30 tacrolimus-treated patients. Two biallelic polymorphisms of the TGF-beta 1 gene were studied at codon 10 (at position +869) and at codon 25 (at position +915) in patients from the examined group and in 108 healthy volunteers (the control group). Results: The distribution of the high, intermediate, and low TGF-beta 1 producer phenotypes was comparable in all the studied groups and in the healthy controls. The high producer phenotype was more frequent in patients with GO. TGF-01 levels in the CsA group showed correlation with the phenotypes. The lowest incidence of GO was observed in the 10C/C genotype, whereas the highest was observed in the 10T/C genotype. Conclusion: High and intermediate TGF-beta 1 producer phenotypes and heterozygous genotype 10T/C might be considered risk factors for GO in patients treated with CsA.