Regulatory T Cells in the Context of New-Onset Diabetes After Renal Transplant: A Single-Center Experience

New-onset diabetes mellitus after transplant (NODAT) is a well-known complication of renal transplant that severely affects graft and patient survival. It is necessary to explore further risk factors and reveal the underlying pathomechanism.

Renal transplants performed between January 2010 and June 2018 were involved. Exclusion criteria were the recipient age younger than 18 years, follow-up period less than 6 months, and patients with diabetes at the time of transplant. Only primary kidney transplants were involved in our study, which totaled 223 cases. Besides donor and recipient demographic data, the type of immunosuppression, the average fasting glucose level, and T-subset profiles were compared.

Of 223 cases there were 33 patients (14.8%) with NODAT (17 female; mean age, 54.2 [SD, 10.3] years; mean body mass index [calculated as weight in kilograms divided by height in meters squared], 27.8 [SD, 5.1]; mean follow-up, 43.3 [SD, 25.5] months). The control group consisted of 190 patients. The average fasting blood glucose level was higher in the NODAT group vs the control group (P < .001). The average fasting blood glucose level above diabetic threshold (≥7 mmol/L) was in association with a 6-fold higher risk of NODAT (odds ratio, 5.86; 95% CI, 2.46-13.97; P < .001). Absolute value of CD4⁺CD25^brightCD127^dim regulatory T cells was lower in the NODAT group at the first month after transplant (P = .048) Immunosuppressive protocol and survival data did not differ.

Intensive management of the carbohydrate excursions during the early post-transplant period may decrease the incidence of NODAT. Further investigations will be required to decide whether the reduced CD4⁺CD25^brightCD127dim/regulatory T-cell count contributes the development of NODAT.