Steroid free immunosuppression is associated with enhanced Th1 transcripts in kidney transplantation.

BACKGROUND: Steroid avoidance in immunosuppression in kidney transplantation offers several metabolic advantages, however it is associated with higher early acute rejection rate. Cellular and molecular mechanisms of this phenomenon remain poorly understood. METHODS: In this single center observational study, low-risk kidney transplant recipients randomized into large multicenter prospective ADVANCE trial with steroid avoidance/early withdrawal and center standard of care treated patients were monitored for 12months. The expressions of 28 transcripts, associated with alloimmune response and operational tolerance, were evaluated in the peripheral blood using RT-qPCR at 0, 7, 14, 90 and 365 postoperative days (POD) and in the protocol graft biopsy at 3months while lymphocyte subpopulations were analyzed by flow-cytometry within the follow-up. RESULTS: Both steroid avoidance and withdrawal regimens were associated with significantly higher granzyme B (GZMB) transcript at POD 14 and perforin 1 (PRF1) transcript at POD 7. The higher interleukin 2 (IL-2) expression at POD 7 was detected only in the steroid avoidance group. Initial steroids decreased the expression SH2D1B transcript at POD14 and there were no further differences in other operational tolerance transcripts among groups. The statistically significant decrease in absolute numbers of peripheral NK cells in the first 14days was observed in the standard of care group only. There were no differences in analyzed intrarenal transcripts in 3-month biopsies among groups. CONCLUSIONS: The enhanced expression of some of Th1 associated transcripts and limited effects on NK cells of steroid avoidance immunosuppression suggest higher susceptibility for early acute rejection.

Effect of induction therapy on the expression of molecular markers associated with rejection and tolerance.

BACKGROUND: Induction therapy can improve kidney transplantation (KTx) outcomes, but little is known about the mechanisms underlying its effects. METHODS: The mRNA levels of T cell-related genes associated with tolerance or rejection (CD247, GZMB, PRF1, FOXP3, MAN1A1, TCAIM, and TLR5) and lymphocyte subpopulations were monitored prospectively in the peripheral blood of 60 kidney transplant recipients before and 7, 14, 21, 28, 60, 90 days, 6 months, and 12 months after KTx. Patients were treated with calcineurin inhibitor-based triple immunosuppression and induction with rabbit anti-thymocyte globulin (rATG, n = 24), basiliximab (n = 17), or without induction (no-induction, n = 19). A generalized linear mixed model with gamma distribution for repeated measures, adjusted for rejection, recipient/donor age and delayed graft function, was used for statistical analysis. RESULTS: rATG treatment caused an intense reduction in all T cell type population and natural killer (NK) cells within 7 days, then a slow increase and repopulation was observed. This was also noticed in the expression levels of CD247, FOXP3, GZMB, and PRF1. The basiliximab group exhibited higher CD247, GZMB, FOXP3 and TCAIM mRNA levels and regulatory T cell (Treg) counts than the no-induction group. The levels of MAN1A1 and TLR5 mRNA expressions were increased, whereas TCAIM decreased in the rATG group as compared with those in the no-induction group. CONCLUSION: The rATG induction therapy was associated with decreased T and NK cell-related transcript levels and with upregulation of two rejection-associated transcripts (MAN1A1 and TLR5) shortly after KTx. Basiliximab treatment was associated with increased absolute number of Treg cells, and increased level of FOXP3 and TCAIM expression.

CD14+CD16+ and CD14+CD163+ monocyte subpopulations in kidney allograft transplantation.

BACKGROUND: Monocytes represent a heterogeneous population of cells subdivided according to the expression level of membrane antigens. A pro-inflammatory (intermediate/nonclassical) subpopulation of monocytes is defined by expression of CD16. CD163 seems to be characteristically preferentially expressed by immunosuppressive monocytes. The aim of our study was to evaluate the distribution of monocyte subpopulations in 71 patients with kidney allograft transplantation. RESULTS: The phenotype was evaluated by flow cytometry in defined time points. The proportions of peripheral CD14+CD16+ monocytes were downregulated immediately after the kidney transplantation and basiliximab treatment partially attenuated this trend. The transient downregulation of the CD14+CD16+ subpopulation was adjusted to basal values in two months. The proportions of CD14+CD163+ monocytes were transiently upregulated early after the kidney transplantation and remained higher during the first month in most patients. In ATG treated patients, the expansion of CD14+CD163+ monocytes was delayed but their upregulation lasted longer. In vitro data showed the direct effect of ATG and methylprednisolone on expression of CD16 and CD163 molecules while basiliximab did not affect the phenotype of cultured monocytes. CONCLUSIONS: We assume from our data that kidney allograft transplantation is associated with modulation of monocyte subpopulations (CD14+CD16+ and CD14+CD163+) partially affected by an immunosuppressive regime used.