Association between Torque teno virus-DNA plasma loads and post-transplantation diabetes mellitus in the first year after kidney transplantation.

BACKGROUND

Torque teno virus (TTV) DNAemia is a surrogate marker of immune function in renal transplant recipients (RTRs), usually peaking around 3 months after transplantation. Post-transplantation diabetes mellitus (PTDM), a condition with impaired immune response, is common after renal transplantation, but its relationship with TTV replication remains unclear.

METHODS

In this retrospective study, TTV-DNA loads were analysed in 303 plasma samples from 93 RTRs collected shortly after transplantation and at 3, 6, and 12 months. Clinical and laboratory parameters, including glycaemic status, were assessed. 17 patients (18.3%) developed PTDM.

RESULTS

As expected, TTV-DNA plasma loads peaked at 3 and 6 months in the cohort. Upon multivariate analysis, time after transplantation (p < 0.001), tacrolimus trough levels, (p = 0.001), and HbA1c (p = 0.012) were associated with TTV-DNA plasma loads. Patients with PTDM, but not with pre-existing diabetes mellitus, showed significantly higher TTV-DNAemia at 3 months (p = 0.03) and 6 months (p = 0.01) after transplantation compared to non-diabetic patients. No significant group differences were observed for cumulative prednisolone dose, tacrolimus trough levels and induction therapy. Although patients with PTDM were older, age contributed only marginally to TTV-DNAemia. Opportunistic viral infections tended to occur more frequently in patients with PTDM.

CONCLUSIONS

In conclusion, PTDM but not pre-existing diabetes was associated with elevated TTV-DNA plasma loads early after transplantation in this retrospective cohort analysis. Patients with PTDM also showed a trend towards more opportunistic infections, although this observation should be interpreted cautiously given the small number of events. These findings suggest a potential association between PTDM and altered immune regulation in RTRs that warrants further investigation.