Interleukin-6 gene polymorphism in renal transplant patients with and without gingival overgrowth

To determine whether there is an association between genotypes of interleukin-6 (IL-6) and gingival overgrowth in kidney transplant patients.

Sixty-three unrelated kidney transplant patients suffering from gingival overgrowth as well 125 control transplant patients without overgrowth were enrolled into the study. Gingival overgrowth was assessed by two independent periodontal specialists at 6 months after transplantation. During the post-transplant period, all patients were given medication, which included cyclosporin A, diltiazem or verapamil, prednisone, and azathioprine. IL-6 polymorphism was determined using the polymerase chain reaction-restriction fragment length polymorphism assay.

In kidney transplant patients suffering from gingival overgrowth mean score of gingival overgrowth was 1.41+/-0.64, whereas in control subjects it was 0.0. Patients with gingival overgrowth induced by immunosuppressive medication were characterized by genotypes similar to the controls distribution of IL-6. There were no significant differences of analyzed genotypes' distribution, i.e. -174G/G, -174G/C and -174C/C between patients with gingival overgrowth 33.3%, 39.7%, 27.0% and without gingival overgrowth 30.4%, 49.6% and 20.0%, respectively. The risk of gingival overgrowth was the highest among patients carrying -174C/C genotype (OR 1.48), but did not differ markedly from the other genotypes, i.e. -174G/G (OR 1.15) and -74G/C (OR 0.67). Similar to genotypes, the distribution of alleles was similar in patients with gingival overgrowth and healthy gingiva. The -174G allele was found in 53.2% and 46.8% of subjects whereas -174C allele was revealed in 46.8% and 44.8% of patients with and without gingival overgrowth, respectively. The evaluated risk of gingival overgrowth in patients with -174G allele was 1.09 versus those with healthy gingiva. The medication regimen administered in both groups of the study was comparable.

No association between the IL-6 gene polymorphism and gingival overgrowth was revealed in kidney transplant patients administered cyclosporin A as a principal immunosuppressive agent.