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

From a Biomarker to Targeting in a Proof-Of-Concept Trial

Background There is high medical need for safe long-term immunosuppression monotherapy in kidney transplantation. Selective targeting of post-transplant alloantigen-(re)activated effector-T cells by anti-TNF antibodies after global T cell depletion may allow safe drug minimization, however, it is unsolved what might be the best maintenance monotherapy. Methods In this open, prospective observational single-centre trial, 20 primary deceased donor kidney transplant recipients received 2x20 mg Alemtuzumab (d0/d1) followed by 5 mg/kg Infliximab (d2). For 14 days all patients received only tacrolimus, then they were allocated to either receive tacrolimus (TAC, n = 13) or sirolimus (SIR, n = 7) monotherapy, respectively. Protocol biopsies and extensive immune monitoring were performed and patients were followed-up for 60 months. Results TAC-monotherapy resulted in excellent graft survival (5yr 92%, 95%CI: 56.6–98.9) and function, normal histology, and no proteinuria. Immune monitoring revealed low intragraft inflammation (urinary IP-10) and hints for the development of operational tolerance signature in the TAC- but not SIR-group. Remarkably, the TAC-monotherapy was successful in all five presensitized (ELISPOT+) patients. However, recruitment into SIR-arm was stopped (after n = 7) because of high incidence of proteinuria and acute/chronic rejection in biopsies. No opportunistic infections occurred during follow-up. Conclusions In conclusion, our novel fast-track TAC- monotherapy protocol is likely to be safe and preliminary results indicated an excellent 5-year outcome, however, a full–scale study will be needed to confirm our findings. Trial Registration EudraCT Number: 2006-003110-1

Molecular Patterns of Subclinical and Clinical Rejection of Kidney Allograft: Quantity Matters

Background/Aims: Subclinical rejection diagnosed from protocol biopsies is thought to be a risk factor of long- term allograft dysfunction. The reason why in some patients subclinical rejection does not represent risk for progression is not fully understood. Methods: The intragraft expression of 376 target genes involved in chemokine defense, apoptosis, inflammation, tolerance and TGF-β signalling pathways was measured using quantitative real-time RT-PCR (2-∆∆Ct) method in subclinical inflammation (SCI, n=10), clinical inflammation in acute T-cell mediated rejection (CI, n=10) and no rejection samples (n=9). Results: Clinical inflammation group showed a increased expression of genes for chemotaxis mediating cytokines (CCL1, CCL17, CCL24, CCL25, CCL26), cytokine receptors (CCR1, CCRL2, IL1RAPL2, CXCR5), proinflammatory cytokines (IL12A, LTA), inflammatory mediator (PTAFR), complement protein C3, executioner protein of apoptosis (CASP7), growth factor (TGFA), colony stimulating factor (CSF-2), proteins involved in dendritic cells differentiation and interaction (CD209, LAMP3), regulation of immune response (LILRB2, LILBRB4). The quantitative difference in transcripts signature between SCI and CI is consistent with stronger proinflammatory setting of CI. Prostaglandin E2 receptor gene expression was independently associated with lower risk of further graft function deterioration (OR 0.11, CI 0.01-0.78, pConclusion: Subclinical acute kidney inflammation has transcriptional profile of immune injury of lower extend compared to clinical acute inflammation

Sequential Targeting of CD52 and TNF Allows Early Minimization Therapy in Kidney Transplantation: From a Biomarker to Targeting in a Proof-Of-Concept Trial.

There is high medical need for safe long-term immunosuppression monotherapy in kidney transplantation. Selective targeting of post-transplant alloantigen-(re)activated effector-T cells by anti-TNF antibodies after global T cell depletion may allow safe drug minimization, however, it is unsolved what might be the best maintenance monotherapy.In this open, prospective observational single-centre trial, 20 primary deceased donor kidney transplant recipients received 2x20 mg Alemtuzumab (d0/d1) followed by 5 mg/kg Infliximab (d2). For 14 days all patients received only tacrolimus, then they were allocated to either receive tacrolimus (TAC, n = 13) or sirolimus (SIR, n = 7) monotherapy, respectively. Protocol biopsies and extensive immune monitoring were performed and patients were followed-up for 60 months.TAC-monotherapy resulted in excellent graft survival (5yr 92%, 95%CI: 56.6-98.9) and function, normal histology, and no proteinuria. Immune monitoring revealed low intragraft inflammation (urinary IP-10) and hints for the development of operational tolerance signature in the TAC- but not SIR-group. Remarkably, the TAC-monotherapy was successful in all five presensitized (ELISPOT+) patients. However, recruitment into SIR-arm was stopped (after n = 7) because of high incidence of proteinuria and acute/chronic rejection in biopsies. No opportunistic infections occurred during follow-up.In conclusion, our novel fast-track TAC-monotherapy protocol is likely to be safe and preliminary results indicated an excellent 5-year outcome, however, a full-scale study will be needed to confirm our findings.EudraCT Number: 2006-003110-18

Distribution of patients in SIR and TAC groups depending on the pretransplant donor specific T-cell alloimmune response assessed by IFN-γ Elispot.

<p>Negative group: <20 spots/ 300 000 PBMC; positive group: >20 spots/ 300 000 PBMC.</p

List of B cell associated genes found to be differentially expressed within the particular group comparison.

<p>Annotation data are from <a href="http://www.uniprot.org/" target="_blank">http://www.uniprot.org/</a> and <a href="http://www.genecards.org/" target="_blank">http://www.genecards.org/</a>. In Tacrolimus/Sirolimus comparison fold change was calculated from gene expression medians of all measured time-points in particular groups. In rejecting and non-rejecting patients only samples collected at later time points (M2, M3, M6 and M12) were used to calculate medians of gene expression.</p

Rejection-free interval (A), defined as the interval between the time of transplantation and the first biopsy proven allograft rejection event (acute T-cell mediated rejection or acute/chronic humoral rejection) and proteinuria-free interval (B), as the interval between the time of transplantation and the first observed proteinuria >1g/24 hours shown in days by treatment group.

<p>P values were determined by log-rank analysis.</p

Heat map of B-cell specific genes differentially expressed between TAC (violet) and SIR-group (yellow) with stronger expression in TAC samples.

<p>Heat map of B-cell specific genes differentially expressed between TAC (violet) and SIR-group (yellow) with stronger expression in TAC samples.</p

Validation of microarray analysis of blood samples by qRT-PCR of graft biopsies.

<p>The comparison of TAC- and SIR- group of patients and of patients with /without rejection event within 12 months posttransplant. All data are presented as mean±SEM. P values shown under the graphs indicate statistically significant difference in gene expression calculated by GLM mixed model.</p

Severe adverse effects within 12 and 60M of follow-up in SIR- and TAC groups.

<p>Severe adverse effects within 12 and 60M of follow-up in SIR- and TAC groups.</p