Serum 25-Hydroxyvitamin D Level Is Not Related to Regulatory T Cells or Kidney Function in Renal Transplant Recipients

Abstract Background Vitamin D and regulatory T cells (Tregs) are both involved in promoting peripheral tolerance and limiting chronic inflammatory diseases. Renal transplant recipients (RTRs) are likely to have low vitamin D levels, which may influence their immune status. Aim The aim of our study was to assess the usefulness of serum 25-hydroxyvitamin D (25(OH)D) and Tregs in estimation of the protolerogenic milieu in RTRs within 1 year after kidney transplantation. Methods 26 RTRs (15M/11F, aged 49.1 ± 15.4 years) 3 to 13 months after kidney transplantation and 24 healthy volunteers were enrolled for the study. The serum level of 25(OH)D was measured with ELISA and peripheral blood immune cell populations (T lymphocytes, helper T lymphocytes, and Tregs) were assessed by flow cytometry. Results Severe 25(OH)D deficiency ( r s  = −0.45, P  = .023), but 25(OH)D was not related to any other cell population or kidney function. Conclusion The results of our study suggest that serum 25(OH)D is not sufficiently reflective of vitamin D status to apply this measure in assessment of protolerogenic milieu in RTRs.