Dysregulation of Th17 cells during the early post-transplant period in patients under calcineurin inhibitor based immunosuppression

Innate and Adaptive Immune Responses in Intestinal Transplant Rejection: Through the Lens of Inflammatory Bowel and Intestinal Graft-Versus-Host Diseases

Intestinal transplantation is a life-saving procedure utilized for patients failing total parenteral nutrition. However, intestinal transplantattion remains plagued with low survival rates and high risk of allograft rejection. The authors explore roles of innate (macrophages, natural killer cells, innate lymphoid cells) and adaptive immune cells (Th1, Th2, Th17, Tregs) in inflammatory responses, particularly inflammatory bowel disease and graft versus host disease, and correlate these findings to intestinal allograft rejection, highlighting which effectors exacerbate or suppress intestinal rejection. Better understanding of this immunology can open further investigation into potential biomolecular targets to develop improved therapeutic treatment options and immunomonitoring techniques to combat allograft rejection and enhance patient lives.

RORγt inverse agonist TF-S14 inhibits Th17 cytokines and prolongs skin allograft survival in sensitized mice

Chronic antibody mediated rejection (AMR) is the major cause of solid organ graft rejection. Th17 contributes to AMR through the secretion of IL17A, IL21 and IL22. These cytokines promote neutrophilic infiltration, B cell proliferation and donor specific antibodies (DSAs) production. In the current study we investigated the role of Th17 in transplant sensitization. Additionally, we investigated the therapeutic potential of novel inverse agonists of the retinoic acid receptor-related orphan receptor gamma t (RORγt) in the treatment of skin allograft rejection in sensitized mice. Our results show that RORγt inverse agonists reduce cytokine production in human Th17 cells in vitro. In mice, we demonstrate that the RORγt inverse agonist TF-S14 reduces Th17 signature cytokines in vitro and in vivo and leads to blocking neutrophilic infiltration to skin allografts, inhibition of the B-cell differentiation, and the reduction of de novo IgG3 DSAs production. Finally, we show that TF-S14 prolongs the survival of a total mismatch grafts in sensitized mice. In conclusion, RORγt inverse agonists offer a therapeutic intervention through a novel mechanism to treat rejection in highly sensitized patients.

Pretransplant, Th17 dominant alloreactivity in highly sensitized kidney transplant candidates

Introduction

Sensitization to donor human leukocyte antigen (HLA) molecules prior to transplantation is a significant risk factor for delayed access to transplantation and to long-term outcomes. Memory T cells and their cytokines play a pivotal role in shaping immune responses, thereby increasing the risk of allograft rejection among highly sensitized patients. This study aims to elucidate the precise contribution of different CD4+ memory T cell subsets to alloreactivity in highly sensitized (HS) kidney transplant recipients.

Methods and results

Stimulation of peripheral blood mononuclear cells (PBMC) with various polyclonal stimulating agents to assess non-specific immune responses revealed that HS patients exhibit elevated immune reactivity even before kidney transplantation, compared to non-sensitized (NS) patients. HS patients' PBMC displayed higher frequencies of CD4+ T cells expressing IFNγ, IL4, IL6, IL17A, and TNFα and secreted relatively higher levels of IL17A and IL21 upon stimulation with PMA/ionomycin. Additionally, PBMC from HS patients stimulated with T cell stimulating agent phytohemagglutinin (PHA) exhibited elevated expression levels of IFNγ, IL4 and, IL21. On the other hand, stimulation with a combination of resiquimod (R848) and IL2 for the activation of memory B cells demonstrated higher expression of IL17A, TNFα and IL21, as determined by quantitative real-time PCR. A mixed leukocyte reaction (MLR) assay, employing third-party donor antigen presenting cells (APCs), was implemented to evaluate the direct alloreactive response. HS patients demonstrated notably higher frequencies of CD4+ T cells expressing IL4, IL6 and IL17A. Interestingly, APCs expressing recall HLA antigens triggered a stronger Th17 response compared to APCs lacking recall HLA antigens in sensitized patients. Furthermore, donor APCs induced higher activation of effector memory T cells in HS patients as compared to NS patients.

Conclusion

These results provide an assessment of pretransplant alloreactive T cell subsets in highly sensitized patients and emphasize the significance of Th17 cells in alloimmune responses. These findings hold promise for the development of treatment strategies tailored to sensitized kidney transplant recipients, with potential clinical implications.

Therapeutic effect of multiple functional minicircle vector encoding anti-CD25/IL-10/CXCR3 in allograft rejection model

BACKGROUND/AIMS

We previously proposed minicircle vector technology as the potential platform for the development and production of new biologics. In this study, we have designed a novel target molecule for the treatment of allograft rejection and evaluated its feasibility as the therapeutic agent in this disease using the minicircle vector system.

METHODS

We engineered vectors to carry cassette sequences for anti-CD25, interleukin-10 (IL-10), and C-X-C motif chemokine receptor 3 (CXCR3) fusion protein, and then isolated minicircle vectors from the parent vectors. We verified the substantial production of anti-CD25/IL-10/CXCR3 fusion protein from minicircles and their duration in HEK293T cells and mice models. We also evaluated whether minicircle-derived anti-CD25/IL-10/CXCR3 has therapeutic effects in a skin allograft in mice model.

RESULTS

We confirmed the production of anti-CD25/IL-10/CXCR3 from minicircle by its significant availability in cells transfected with the minicircle and in its conditioned media. After a single injection of minicircle by hydrodynamic injection via mouse tail vein, luminescence or red fluorescence was maintained until 40 days in the liver tissue, suggesting the production of anti-CD25/IL-10/CXCR3 protein from minicircles via protein synthesis machinery in the liver. Mice treated with the minicircle encoding anti-CD25/IL-10/CXCR3 showed prolonged skin allograft survival times accompanied by improved immunologic regulation e.g., reduction of the lymphocyte population of Th1, Th2, and Th17 and an induction of regulatory T cells.

CONCLUSION

These findings implied that self-generated anti-CD25/IL-10/CXCR3 protein drug by minicircle technology is functionally active and relevant for reducing allograft rejection. The minicircle vector system may be useful for developing new biological drugs, avoiding manufacturing or practical problems.

Combined Analysis of HLA Class II Eplet Mismatch and Tacrolimus Levels for the Prediction of De Novo Donor Specific Antibody Development in Kidney Transplant Recipients

We investigated whether HLA class II eplet mismatch was related to dnDSA development and analyzed its combined impact with tacrolimus levels for kidney transplantation outcomes. A total of 347 kidney transplants were included. HLA Matchmaker was used for the single molecular eplet, total eplet, antibody (Ab)-verified eplet mismatch analyses, and Ab-verified single molecular analysis to identify HLA-DR/DQ molecular thresholds for the risk of dnDSA development. A time-weighted tacrolimus trough level (TAC-C0) of 5 ng/mL and a TAC-C0 time-weighted coefficient variability (TWCV) of 20% were applied to find the combined effects on dnDSA development. A high level of mismatch for single molecular eplet (DQ ≥ 10), total eplet (DQ ≥ 12), Ab-verified eplet (DQ ≥ 4), and Ab-verified single molecular eplet (DQ ≥ 4) significantly correlated with HLA class II dnDSA development. Class II dnDSA developed mostly in patients with low TAC-C0 and high eplet mismatch. In the multivariable analyses, low TAC-C0 and high eplet mismatch showed the highest hazard ratio for the development of dnDSA. No significant combined effect was observed in dnDSA development according to TWCV. In conclusion, the determination of HLA class II eplet mismatch may improve the risk stratification for dnDSA development, especially in conjunction with tacrolimus trough levels.

Polyphenols and Novel Insights Into Post-kidney Transplant Complications and Cardiovascular Disease: A Narrative Review

Kidney transplantation is the preferred treatment for end-stage kidney disease. It is, however, not devoid of complications. Delayed graft function related to ischemia-reperfusion injury (IRI), calcineurin inhibitor (CNI) nephrotoxicity, diabetes, and a particularly high-rate cardiovascular disease (CVD) risk, represent important complications following kidney transplantation. Oxidative stress and chronic low-grade inflammation are mechanisms of disease incompletely abrogated in stable kidney transplant recipient (KTR), contributing to the occurrence of these complications. Polyphenols, bioactive compounds with recognized antioxidant and anti-inflammatory properties have been strongly associated with prevention of CVD in the general population and have been shown to decrease IRI and antagonize CNI nephrotoxicity in animal experimental models, therefore they may have a role in prevention of complications in KTR. This narrative review aims to summarize and discuss current evidence on different polyphenols for prevention of complications, particularly prevention of CVD in KTR, pointing toward the need of further studies with potential clinical impact.

Clinical Trial of Allogeneic Mesenchymal Stem Cell Therapy for Chronic Active Antibody-Mediated Rejection in Kidney Transplant Recipients Unresponsive to Rituximab and Intravenous Immunoglobulin

Clinical trials of biologic agents for chronic active antibody-mediated rejection (CAMR) in kidney transplant recipients (KTRs) have been disappointing. We performed a clinical trial of mesenchymal stem cell (MSC) treatment in KTRs with CAMR unresponsive to rituximab and intravenous immunoglobulin. This study was a phase 1 clinical trial to confirm patient safety. Two patients with CAMR unresponsive to rituximab and intravenous immunoglobulin were included. Each patient received allogeneic MSCs for 4 cycles (1 × 10⁶ cells/kg every other week) via the peripheral vein in the distal arm. We observed adverse events and renal function for 6 months after the final MSC infusion and analyzed changes in immunomodulatory parameters in the peripheral blood between the start of treatment and 3 months after the final MSC infusion. There were no serious adverse events during the study period. Renal function was stable during MSC treatment but gradually decreased between the final MSC infusion and the study endpoint (patient 1: creatinine levels ranged from 3.01 mg/dL to 7.81 mg/dL, patient 2: 2.87 mg/dL to 3.91 mg/dL). In peripheral blood sample analysis between the start of treatment and 3 months after the final MSC infusion, there were similar trends for immunomodulatory markers. Our study showed that there were no serious adverse events for six months after allogeneic MSC treatment in KTRs with CAMR refractory to rituximab and intravenous immunoglobulin, but further studies need to define the efficacy of MSC treatment in CAMR.

Phenotype and molecular signature of CD8+ T cell subsets in T cell- mediated rejections after kidney transplantation

We investigated the phenotype and molecular signatures of CD8+ T cell subsets in kidney-transplant recipients (KTRs) with biopsy-proven T cell-mediated rejection (TCMR). We included 121 KTRs and divided them into three groups according to the pathologic or clinical diagnosis: Normal biopsy control (NC)(n = 32), TCMR (n = 50), and long-term graft survival (LTGS)(n = 39). We used flowcytometry and microarray to analyze the phenotype and molecular signatures of CD8+ T cell subsets using peripheral blood from those patients and analyzed significant gene expressions according to CD8+ T cell subsets. We investigated whether the analysis of CD8+ T cell subsets is useful for predicting the development of TCMR. CCR7+CD8+ T cells significantly decreased, but CD28nullCD57+CD8+ T cells and CCR7-CD45RA+CD8+ T cells showed an increase in the TCMR group compared to other groups (p<0.05 for each); hence CCR7+CD8+ T cells showed significant negative correlations to both effector CD8+ T cells. We identified genes significantly associated with the change of CCR7+CD8+ T, CCR7-CD45RA+CD8+ T, and CD28nullCD57+CD8+ T cells in an ex vivo study and found that most of them were included in the significant genes on in vitro CCR7+CD8+ T cells. Finally, the decrease of CCR7+CD8+ T cells relative to CD28nullCD57+ T or CCR7-CD45RA+CD8+ T cells can predict TCMR significantly in the whole clinical cohort. In conclusion, phenotype and molecular signature of CD8+ T subsets showed a significant relationship to the development of TCMR; hence monitoring of CD8+ T cell subsets may be a useful for predicting TCMR in KTRs.

Sirolimus vs mycophenolate moftile in Tacrolimus based therapy following induction with Antithymocyte globulin promotes regulatory T cell expansion and inhibits RORγt and T-bet expression in kidney transplantation

BACKGROUND

Accumulating evidence suggests that regulatory T cells (Tregs) have a crucial role in immune tolerance and long-term graft survival. However, the influence of immunosuppressive drugs on the level of Tregs has not been fully understood. Therefore we prospectively compare the effect of two different calcineurin inhibitor (CNI)-based immunosuppression protocols on Tregs frequencies and expression of regulatory and effector T cell-related genes in renal transplant recipients.

METHODS

The study included 24 renal transplant recipients who received induction therapy (Antithymocyte globulin) and were on triple immunosuppressive therapy so that one group was on Tacrolimus (Tac), mycophenolate moftile (MMF) and prednisolone (P) whereas another group was on Tac, Sirolimus (SRL) and P. The frequency of circulating Treg cells was analyzed by flow cytometry before and 4 months after transplantation. Also, the mRNA expression of FOXP3, T-bet, GATA3 and RORγt was examined by quantitative RT-PCR before and 4 months after transplantation.

RESULTS

Compared to baseline, the frequency of CD4+ CD25+ FOXP3+ Treg cells was significantly increased in the all patients following transplantation. Patients who received Tac/MMF had significantly higher CD4+ CD25+ FOXP3+ Treg cells compared to patients who received Tac/SRL. There was no a significant difference in the frequency of CD3+CD8+ CD28- Tregs between two different calcineurin inhibitor (CNI)-based immunosuppression protocols. FOXP3 mRNA levels in the patients who received Tac/MMF were increased 4 months after transplantation and the expression was significantly higher than patients who received Tac/SRL. On the other hand, T-bet and RORγt expression levels were significantly lower in the Tac/SRL group in comparison to Tac/MMF group. We did not observe any significant difference in GATA3 mRNA level between the two groups.

CONCLUSIONS

Our results suggest that although Tac/MMF-containing immunosuppressive regimen could significantly increase the frequency of CD4+ CD25+ FOXP3+ Tregs, unlike to Tac/SRL-containing regimen, it could not significantly decrease the expression levels of RORγt and T-bet.

Dissecting the Multiplicity of Immune Effects of Immunosuppressive Drugs to Better Predict the Risk of de novo Malignancies in Solid Organ Transplant Patients

De novo malignancies constitute an emerging cause of morbidity after solid organ transplant (SOT), significantly affecting the long-term survival of transplant recipients. Pharmacologic immunosuppression may functionally impair the immunosurveillance in these patients, thereby increasing the risk of cancer development. Nevertheless, the multiplicity and heterogeneity of the immune effects induced by immunosuppressive drugs limit the current possibilities to reliably predict the risk of de novo malignancy in SOT patients. Therefore, there is the pressing need to better characterize the immune dysfunctions induced by the different immunosuppressive regimens administered to prevent allograft rejection to tailor more precisely the therapeutic schedule and decrease the risk of de novo malignancies. We herein highlight the impact exerted by different classes of immunosuppressants on the most relevant immune cells, with a particular focus on the effects on dendritic cells (DCs), the main regulators of the balance between immunosurveillance and tolerance.

Effects of resveratrol on Th17 cell-related immune responses under tacrolimus-based immunosuppression

BACKGROUND

We previously reported that tacrolimus (Tac) does not decrease T helper 17 cells (Th17) response in kidney transplantation. In this study, we evaluated whether Resveratrol (Resv) has immunosuppressive effects by decreasing Th17 responses in Tac-based immunosuppression.

METHODS

We investigated the effects of Resv under Tac-treatment conditions, on CD4+ T cell differentiation to Th17 cells in peripheral blood mononuclear cells (PBMCs), and proliferation of CD4+ T cells co-cultured with human renal proximal tubular epithelial cells (HRPTEpiCs). The effects of Resv on Th17 cells were tested in the murine skin transplant model.

RESULTS

In PBMCs, Tac did not but combination of Tac and Resv further suppressed Th17 immune response. In the co-culture study, combination of Resv to Tac significantly decreased HRPTEpiC-induced T cell proliferation compared to Tac alone. Resv treatment in the Jurkat cell induced the expression of AMP-activated protein kinase and suppressed the expression of mammalian target of rapamycin (mTOR), suggesting blocking Th17 pathway by Resv. In the murine skin transplant model, combination of Resv to Tac significantly prolonged skin graft survival accompanied by the suppression of Th17 cells, compared to either the Tac-alone or control groups.

CONCLUSION

The results of our study suggest that Resv provides additional immunosuppressive effects to Tac by suppressing effector CD4+ T cells, especially Th17 cells, in the transplantation setting.

Th1, Th2, Th17 cell subsets in two different immunosuppressive protocols in renal allograft recipients (Sirolimus vs mycophenolate mofetil): A cohort study

Long-term use of calcineurin inhibitors (CNI) is associated with nephrotoxicity, which is an important cause of renal dysfunction. Therefore, CNI-minimization strategies which decrease the CNI nephrotoxicity under the protection of additional immunosuppressant drugs have been developed. The aim of current cohort study was to compare the effect of two immunosuppressive protocols [tacrolimus (TAC) in combination with mycophenolate mofetil (MMF) and prednisolone (PRED) versus TAC in combination with sirolimus (SRL) and prednisolone] on the frequency of T helper cell subsets (Th1, Th2 and Th17 cells) and their associated cytokine (IFN-γ, IL-4 and IL-17A) levels in renal allograft recipients. In this study, renal transplant recipients who received induction therapy (Antithymocyte globulin) and were also on triple immunosuppressive therapy were included and divided in to two groups: Group A was comprised 14 patients who received TAC, MMF and PERD whereas group B was composed of 10 patients who received TAC, SRL and PERD. The frequency of Th1, Th2 and Th17 cells in the peripheral blood mononuclear cells (PBMCs) of the patients was analyzed by flow cytometry before and 4 months after transplantation. In addition, IFN-γ, IL-4 and IL-17A concentrations in PBMC culture supernatants of patients before and 4 months after transplantation were quantified by ELISA. The results of our study showed that TAC, MMF and PRED protocol did not diminish the frequency of Th17 cells at 4 months post-transplantation (5% ± 2.5) compared with pre-transplantation (2.3% ± 1; P < 0.05). However, Th17 (3.6% ± 1.5 pre-transplantation vs 2.2% ± 0.9 at 4 months post-transplantation; P < 0.05), Th2 (1.4% ± 0.3 pre-transplantation vs 0.8% ± 0.4 at 4 months post-transplantation; P < 0.05) cell subsets and IL-4 concentration (71.5 pg/ml ± 12 pre-transplantation vs 62.5 pg/ml ±4.4 at 4 months post-transplantation; P < 0.05) were significantly decreased after transplantation in patients who had received SRL, TAC and PRED. In conclusion, the data of the current study suggest that using reduced dose of TAC in SRL, TAC and PRED protocol is in favor of allograft survival; however a cohort study with larger sample size is needed for confirming our results.

Clinical impact of complement (C1q, C3d) binding De Novo donor-specific HLA antibody in kidney transplant recipients

Introduction

Complement binding activity of donor-specific HLA antibodies (DSA) has been suggested as a new tool to stratify immunologic risk in kidney transplantation (KT). The objective of this study was to evaluate the clinical implication of C1q/C3d binding activity of de novo DSA (dnDSA) in KT recipients.

Material and methods

A total of 161 pretransplant DSA-negative recipients were monitored for dnDSA at the time of biopsy. C1q/C3d binding activities of dnDSA were assessed using C1qScreen assay (One lambda, USA) and Lifecodes C3d detection assay (Immucor, USA), respectively. Clinical outcomes including biopsy-proven antibody mediated rejection (AMR), C4d detection and post-biopsy graft survival were investigated.

Results

De-novo DSAs were detected in fifty-four (33.5%) patients (HLA class I only, n = 19; class II only, n = 29; both class I and II, n = 6). Of them, complement binding activities were detected in 26 (48.1%) patients, including 17 C1q+ and 24 C3d+ patients. Both C1q and C3d positivity were associated with increased mean fluorescence intensity values of dnDSA. Complement binding activity of dnDSA enhanced the incidence of AMR (25.0% in C1q-C3d-, 36.4% in C1q+/C3d- or C1q-/C3d+, and 60.0% in C1q+/C3d+ patients) (P <0.001). The incidence of AMR was not different between patients with C1q+ and those with C3d+ dnDSA (64.7%, 11/17 versus 45.8%, 11/24, P = 0.238). In comparison between C1q and C3d assay according to HLA specificity, C1q+ HLA class I ± II dnDSA was the best predictor for AMR (odds ratio: 27.2). C1q+/C3d+ dnDSA was associated with more C4d deposition in allograft tissue and inferior post-biopsy graft survival. Clinical outcomes were not significantly different between C1q+ and C3d+ dnDSA-positive patients.

Conclusion

Detection of complement binding activity using both C1q and C3d assays can be a further prognostic marker for predicting AMR and allograft outcome in dnDSA+ kidney transplant patients.

Reduced TCR Signaling Contributes to Impaired Th17 Responses in Tolerant Kidney Transplant Recipients

BACKGROUND

The development of spontaneous kidney transplant tolerance has been associated with numerous B cell-related immune alterations. We have previously shown that tolerant recipients exhibit reduced B-cell receptor signalling and higher IL-10 production than healthy volunteers. However, it is unclear whether cluster of differentiation (CD)4 T cells from tolerant recipients also display an anti-inflammatory profile that could contribute to graft maintenance.

METHODS

CD4 T cells were isolated from kidney transplant recipients who were identified as being tolerant recipients, patients with chronic rejection or healthy volunteers. CD4 T cells from the 3 groups were compared in terms of their gene expression profile, phenotype, and functionally upon activation.

RESULTS

Gene expression analysis of transcription factors and signalling proteins, in addition to surface proteins expression and cytokine production, revealed that tolerant recipients possessed fewer Th17 cells and exhibited reduced Th17 responses, relative to patients with chronic rejection or healthy volunteers. Furthermore, impaired T-cell receptor signalling and altered cytokine cooperation by monocytes contributed to the development of Th17 cells in tolerant recipients.

CONCLUSIONS

These data suggest that defective proinflammatory Th17 responses may contribute to the prolonged graft survival and stable graft function, which is observed in tolerant recipients in the absence of immunosuppressive agents.

Clinical significance of Th17 cells in kidney transplantation

Transplantation research has focused on cytotoxic T-cell and plasma cell/B-cell-targeted strategies, but little attention has been paid to the role of T helper 17 (Th17) cells in allograft dysfunction. However, accumulating evidence suggests that Th17 cells contribute to the development of acute and chronic allograft injury after transplantation of various organs, including the kidney. This review summarizes recent reports on the role of Th17 cells in kidney transplantation. Means of improving allograft outcomes by targeting the Th17 pathway are also suggested.

Clinical significance of CD161+CD4+ T cells in the development of chronic antibody-mediated rejection in kidney transplant recipients

In this study, we investigated whether CD161⁺CD4⁺ T cells can reflect the Th17 pathway in kidney transplant recipients (KTRs) and investigated the clinical significance of this cell type in chronic antibody-mediated rejection (cAMR) in KT. First, we investigated the relationship between CD161⁺CD4⁺ T and Th17 cells by flow cytometry and microarray analysis in an in vitro study. Second, we compared the proportion of T cell subsets including CD161⁺CD4⁺ T cells in cAMR (n = 18), long-term graft survival (LTGS) (n = 46), and interstitial fibrosis/tubular atrophy (IF/TA) (n = 22). We compared CD161⁺ cell infiltration between cAMR and IF/TA and also examined the effect of CD161⁺ T cells on human renal proximal tubular epithelial cells (HRPTEpiC). In flow cytometry, the proportion of CD161⁺CD4⁺ T cells showed a significant correlation with the proportion of Th17 cells. In microarray analysis, transcripts associated with the Th17 pathway such as IL18RAP, IL-18R1, IL23R, IL12RB2, RORC, TBX21, and EOMES were upregulated in CD161⁺ cells compared with CD161^- cells. In an ex vivo study, only CD161⁺CD4⁺ T cells showed a significant increase in the cAMR group compared with IF/TA and LTGS groups. In allograft tissue, CD161⁺ cells showed a higher level of infiltration in the cAMR group than the IF/TA group. Lastly, CD161⁺ T cells increased the production of inflammatory cytokines from HRPTEpiC in a dose-dependent manner. This study suggests that monitoring of CD161⁺ T cells can be useful to detect the progression of cAMR.

Clinical significance of CCR7+CD8+ T cells in kidney transplant recipients with allograft rejection

The regulatory function of CCR7⁺CD8⁺ T cells against effector T-cells involved in T-cell mediated rejection (TCMR) in kidney transplant recipients was investigated. In vitro experiments explored the ability of CCR7⁺CD8⁺ T cells to suppress T-cell proliferation under T-cell activation conditions or during coculture with human renal proximal tubular epithelial cells (HRPTEpiC). In an ex vivo experiment, the proportion of CCR7⁺/CD8⁺, FOXP3⁺/CCR7⁺CD8⁺ T and effector T-cell subsets were compared between the normal biopsy control (NC, n = 17) and TCMR group (n = 17). The CCR7⁺CD8⁺ T cells significantly suppressed the proliferation of CD4⁺ T cells and significantly decreased the proportion of IFN-γ⁺ and IL-17⁺/CD4⁺ T cells and inflammatory cytokine levels (all p < 0.05). After coculturing with HRPTEpiC, CCR7⁺CD8⁺ T cells also suppressed T-cell differentiation into IL-2⁺, IFN-γ⁺, and IL-17⁺/CD4⁺ T cells (all p < 0.05). The TCMR group had significantly fewer CCR7⁺/CD8⁺ and FOXP3⁺/CCR7⁺CD8⁺ T in comparison with the NC group, but the proportions of all three effector T-cell subsets were increased in the TCMR group (all p < 0.05). The proportion of CCR7⁺/CD8⁺ T was inversely correlated with those of effector T-cell subsets. The results indicate that CCR7⁺CD8⁺ T cells may regulate effector T-cells involved in TCMR in an in vitro and in an ex vivo transplant model.

Cytomegalovirus (CMV) immune monitoring with ELISPOT and QuantiFERON-CMV assay in seropositive kidney transplant recipients

Although cytomegalovirus (CMV) specific cell-mediated immunity (CMI) has been suggested as a predictive marker for CMV infection, proper CMI monitoring strategy in CMV-seropositive recipients and optimal method are not defined. The aim of this study was to evaluate two interferon gamma release assays during early post-transplant period as a predictor of the development of CMV infection in CMV-seropositive patients. A total of 124 CMV-seropositive recipients who received kidney transplantation from CMV-seropositive donor were prospectively examined. At pre-transplant and post-transplant 1 and 3 months, CMV-CMIs were tested using QuantiFERON-CMV assay (QF-CMV) and CMV specific T cell ELISPOT against CMV pp65 and IE-1 antigens (pp65-ELISPOT, IE-1-ELISPOT). CMV DNAemia occurred in 16 (12.9%) patients within 3 months after transplant. Post-transplant pp65 or IE-1 ELISPOT response, but not QF-CMV, was significantly associated with CMV DNAemia. The pp65 ELISPOT (cut-off; 30 spots/200,000 cells) and IE-1 ELISPOT (10 spots/200,000 cells) at post-transplant 1 month predicted the risk of post-transplant CMV DNAemia (P = 0.019). Negative predictive values (NPV) for protection from CMV DNAemia in case of positive ELISPOT results were 94.5% (95% CI: 86.9–97.8%) and 97.6% (95% CI: 86.3–99.6%) in pp65-ELISPOT and IE-1-ELISPOT assays, respectively. These results suggest that the variability may exist between CMV ELISPOT assays and QF-CMV, and CMV ELISPOT at post-transplant 1 month can identify the risk of CMV DNAemia in seropositive kidney transplant recipients.

Comparison of effects of the tacrolimus and cyclosporine A on the colon anastomosis recovery of rats

Purpose

This study aims to examine and compare the effects of immunosuppressant cyclosporine A (CsA) and tacrolimus (TAC) on colon anastomosis recovery.

Methods

Forty rats were randomly divided into 4 groups. The 4 groups were determined as follows: control group; sham group, given %0.09 NaCl; TAC group, given 0.5 mg/kg/day tacrolimus; and CsA group, given 5 mg/kg/day CsA. A 6-cm midabdomen incision was performed on the rats. An incision of all layers on the right colon was performed. Then anastomosis was undertaken. Laparotomy was performed on the seventh day postoperation. The colon bursting pressures were evaluated, histopathological examinations were undertaken, and E-cadherin expression and tissue hydroxyproline levels were evaluated.

Results

Statistically significant differences were observed among bursting pressures of the groups (P < 0.001). The value was significantly low in TAC and CsA groups when compared to control and sham groups (P < 0.05). The tissue hydroxyproline levels were significantly low in TAC group compared to control group (P = 0.03). Fibroblast density and neovascularization were significantly greater in the control group compared to the TAC group (P < 0.05). Levels of collagen had decreased significantly in TAC group compared to other groups (P < 0.05).

Conclusion

Our study showed that TAC may have a negative effect of colon anastomosis recovery. The lowest anastomosis bursting pressure was detected in TAC group. Also, collagen, hydroxyproline, fibroblast, neovascularization and E-Cadherin levels were comparatively lower in TAC group. CsA did not cause any significant changes to tissue hydroxyproline, collagen, fibroblast, and E-Cadherin levels.

Treatment of psoriasis with etanercept in immunocompromised patients: Two case reports

Tumour necrosis factor (TNF)-α blocking agents have revolutionized the treatment of psoriasis and psoriatic arthritis. Concerns remain about increased susceptibility to infection and onset of malignancies, and the use of TNF-α agents in patients with HIV infection or undergoing immunosuppressant treatment is debated. We report cases of severe plaque psoriasis in a patient with HIV infection and in a liver transplant recipient who were successfully treated with etanercept, an anti-TNF-α agent, without notable side-effects.

Safety and immunologic benefits of conversion to sirolimus in kidney transplant recipients with long-term exposure to calcineurin inhibitors

BACKGROUND/AIMS

Sirolimus (SRL) is a promising immunosuppressant replacingcalcineurin inhibitors (CNIs). This study was performed to evaluate the safetyand immunologic benefits of conversion to SRL in stable kidney transplant (KT)recipients exposed to CNIs for long periods.

METHODS

Fourteen CNI-treated KT recipients with stable renal function for morethan 10 years were included. Either 2 or 3 mg per day of SRL was administeredwhile CNIs were reduced by half starting on day 1, and then stopped 2 weeks afterSRL introduction. The safety of SRL conversion was assessed considering thegraft function, acute rejection, and graft loss. Immunologic alterations were measuredvia serial changes of T cell and B cell subsets after SRL conversion. Adverseeffects of SRL conversion were also evaluated.

RESULTS

Conversion to SRL was successful in nine patients (64.2%). Conversionto SRL preserved graft function as compared to the baseline value (p = 0.115). Noacute rejection or allograft loss was observed during the follow-up period. Immunemonitoring of T and B cells revealed a regulatory T cells increase after SRL conversion (p = 0.028). Most adverse events developed within 6 weeks after SRLconversion, and oral mucositis was the main cause of SRL withdrawal.

CONCLUSIONS

Conversion to SRL can be safe and has immunologic benefits in KTrecipients with long-term CNI exposure. Close monitoring of mucocutaneous adverseevents is, however, required in the early period after SRL conversion.

Clinical Significance of HLA-DQ Antibodies in the Development of Chronic Antibody-Mediated Rejection and Allograft Failure in Kidney Transplant Recipients

With the development of the single antigen beads assay, the role of donor specific alloantibody (DSA) against human leukocyte antigens in kidney transplantation (KT) has been highlighted. This study aimed to investigate the clinical significance of DQ-DSA detected at renal allograft biopsy. We evaluated 263 KT recipients who underwent allograft biopsy and DSA detection at the same time. Among them, 155 patients who were nonsensitized before transplantation were selected to investigate the role of de-novo DQ-DSA. Both the total and nonsensitized subgroup was categorized into 4 groups each according to DSA results as: DQ only, DQ + non-DQ, non-DQ, and no DSA. In the total patient group, post-KT DSA was positive in 79 (30.0%) patients and DQ-DSA was most prevalent (64.6%). In the nonsensitized subgroup, de-novo DSAs were detected in 45 (29.0%) patients and DQ-DSA was also most prevalent (73.3%). The DQ only group showed a significantly longer post-KT duration compared to the other groups (P < 0.05). The overall incidence of antibody-mediated rejection (AMR) was 17.9%. B-DSA, DR-DSA, and DQ-DSA were associated with AMR (P < 0.05), but in the analysis for chronic AMR, only DQ-DSA showed significance in both the total and the nonsensitized subgroup (P < 0.05). On comparison of Banff scores among groups, those representing humoral immunity were significantly dominant in all DSA positive groups compared to the no DSA group (P < 0.05), and higher scores of markers representing chronic tissue injury were more frequently detected in the groups with DQ-DSA. The worst postbiopsy survival was seen in the DQ + non-DQ group of the total patient group, and patients with de-novo DQ-DSA showed poorer graft survival in the nonsensitized subgroup compared to the no DSA group (P < 0.05). In the multivariate analysis, de-novo DQ-DSA was the only significant risk factor associated with late allograft failure (P < 0.05). Our study is the first to demonstrate the association of DQ-DSA with detailed histological findings representing chronic AMR. These findings suggest that the detection of DQ-DSA in nonsensitized patients is significantly associated with the development of chronic AMR and late allograft failure. Therefore monitoring of DQ-DSA not only in sensitized patients, but also nonsensitized patients may be necessary to improve long-term allograft outcomes.

Sirolimus vs cyclosporine after induction with basiliximab does not promote regulatory T cell expansion in de novo kidney transplantation: Results from a single-center randomized trial

Regulatory T cells (Tregs), defined as CD4+CD25+highFoxP3+CD127- cells, could promote tolerance in renal transplantation (Tx). In an open-label, randomized, controlled trial 62 de-novo Tx recipients received induction with basiliximab and cyclosporine A (CsA) for the first month after Tx and then were assigned to treatment with sirolimus (SRL) or CsA and followed up for 2 years. The primary endpoint was to evaluate the effects of induction and maintenance treatments on circulating Tregs, while the secondary endpoint was the assessment of Treg renal infiltration and the relationship between Treg count and clinical outcomes. There were no significant differences in either circulating or tissue Treg number between the two groups. At 1 month post-Tx, all patients presented a profound Treg depletion, followed by a significant increase in Tregs that resulted stable during the follow-up. The same trend was also observed for non-activated Tregs (CD69-) and for other immunocompetent cells (CD4+ and CD8+ T cells, B cells and NK cells). Moreover, the Treg count did not correlate either with renal function or with acute rejection and graft loss. Initial immunosuppression is crucial to regulate circulating Tregs, regardless of subsequent immunosuppressive maintenance regimens. Strategies aiming to promote tolerance should consider the effects of different induction regimens.

The imbalance between Tregs, Th17 cells and inflammatory cytokines among renal transplant recipients

Background

A significant barrier to organ transplantation is the cellular rejection that occurs and mediated by antibodies, T cells, and innate immune cells. This study was aimed to determine the number of CD4⁺CD25⁺Foxp3⁺ Treg, CD4⁺IFN-γ⁻IL-17⁺ Th17, CD4⁺IFN-γ⁺IL-17⁻ Th1 and CD4⁺IFN-γ⁺IL-17⁺ Th1/17 cells in renal transplant recipients (RTR).

Methods

Renal transplantation was performed for a total of 35 patients with end-stage renal failure. The number of CD4⁺CD25⁺Foxp3⁺ Treg, CD4⁺IFN-γ⁻IL-17⁺ Th17, CD4⁺IFN-γ⁺IL-17⁻ Th1 and CD4⁺IFN-γ⁺IL-17⁺ Th1/17 cells, and the serum level of IFN-γ, TNF-α, IL-2, IL-4, IL-6, IL-10, and IL-17 were measured in pre- and post-transplant patients and 10 healthy controls (HC) using flow cytometry and Cytometric Bead Array (CBA). The association between the number of different subsets of CD4⁺ T-cells and clinical parameters were analyzed among the pre- and post-transplant patients, and the healthy controls.

Results

The number of CD4⁺IFN-γ⁻IL-17⁺ Th17, CD4⁺IFN-γ⁺IL-17⁻ Th1 and CD4⁺IFN-γ⁺IL-17⁺ Th1/17 cells were significantly increased in patients with End-Stage Renal Failure (ESRF) compared to the HC. Stratification analysis indicated that AMR (Acute antibody mediated acute rejection), AR (acute rejection) and CR (chronic rejection) groups displayed greater number of CD4⁺IFN-γ⁻IL-17⁺ Th17, CD4⁺IFN-γ⁺IL-17⁻ Th1 and CD4⁺IFN-γ⁺IL-17⁺ Th1/17 cells as well as high level of serum IL-2, IFN-γ, TNF-α and IL-17. But, the AMR, AR and CR groups have shown lower level of CD4⁺CD25⁺Foxp3⁺ T cells and serum IL-10 compared to transplant stable (TS) patients. Moreover, the number of Tregs were negatively correlated with the number of Th17 cells in RTR patients. The number of Tregs and Th17 cells were positively correlated with the eGFR and serum creatinine values, respectively.

Conclusion

The imbalance between different types of CD4⁺ T cells and dysregulated inflammatory cytokines may contribute towards renal transplantation rejection.

Effect of Pretransplant Rituximab Use on Posttransplant Clinical Outcomes in Patients with High Panel Reactive Antibody Scores

BACKGROUND/AIMS

Whether desensitization treatment is needed before kidney transplant (KT) in patients with high panel reactive antibody (PRA) scores but negative cross-matching (XM) tests remains controversial. This study aimed to investigate the effect of pretransplant rituximab (RTX) treatment on clinical outcomes in these patients.

METHODS

The study included 52 patients with PRA >50% but negative XM tests before transplantation. A single dose of RTX was administered before KT in 32 patients (RTX group). The 20 patients without RTX treatment were considered as controls (CON group). We compared the development of acute antibody-mediated rejection (AMR), rejection-free survival, allograft function, allograft and patients' survival rates and infection rates between the 2 groups.

RESULTS

The rate of acute AMR development was significantly lower in the RTX group than in the CON group (p = 0.009), and rejection-free survival in the RTX group was higher than in the CON group (p = 0.042). The 3-year graft and patient survival rates were higher in the RTX group than in the CON group (p = 0.007 and p = 0.037, respectively). There were no significant differences in infection rates between the groups.

CONCLUSIONS

Pretransplant use of RTX improved the post-transplant clinical outcomes in patients with high PRAs but negative XM tests.

Relationship of Interleukin-10 and Transforming Growth Factor-β Levels With Short-Term Graft Function After Kidney Transplantation

INTRODUCTION

We evaluated the relationship of interleukin-10 (IL-10) and transforming growth factor-β (TGF-β) levels with graft function in kidney transplantation patients receiving tacrolimus-based immunosuppression during the early post-transplantation period.

MATERIAL AND METHODS

There were 112 patients who underwent kidney transplantation from live donors between May 2011 and May 2013. Eight patients had at least 1 of the exclusion criteria, and the remaining 104 patients were included in the study. The recipients underwent evaluation for biochemical markers, complete blood count, and creatinine and cytokine (IL-10, TGF-β) levels during the pretransplantation and post-transplantation 6 months.

RESULTS

The creatinine level was negatively correlated with IL-10 and positively correlated with TGF-β levels in both the pretransplantation and early post-transplantation period.

CONCLUSION

Low serum TGF-β and high IL-10 levels at post-transplantation month 6 might have a positive effect on graft survival in living donor kidney recipients on tacrolimus-based immunosuppressive treatment.

Immunological benefits by ginseng through reciprocal regulation of Th17 and Treg cells during cyclosporine-induced immunosuppression

BACKGROUND

It is not clear whether ginseng affects cyclosporine A (CsA)-induced desirable immunosuppressive action. In this study, we evaluated the immunological influence of combined treatment of ginseng with CsA.

METHODS

Using CD4+ T cells from mouse spleens stimulated with the T cell receptor (TCR) or allogeneic antigen-presenting cells (APCs), we examined the differentiation of naïve T cells into T helper 1 (Th1), Th2, Th17, and regulatory T cells (Tregs), and their cytokine production during treatment by Korean Red Ginseng extract (KRGE) and/or CsA. The influence of KRGE on the allogeneic T cell response was evaluated by mixed lymphocyte reaction (MLR). We also evaluated whether signal transducer and activator of transcription 3 (STAT3) and STAT5 are implicated in this regulation.

RESULTS

Under TCR stimulation, KRGE treatment did not affect the population of CD4+interferon gamma (IFNγ)+ and CD4+interleukin (IL)-4+ cells and their cytokine production compared with CsA alone. Under the Th17-polarizing condition, KRGE significantly reduced the number of CD4+IL-17+ cells and CD4+/phosphorylated STAT3 (p-STAT3)+ cells, but increased the number of CD4+CD25+forkhead box P3 (Foxp3)+ cells and CD4+/p-STAT5+ cells compared with CsA alone. In allogeneic APCs-stimulated CD4+ T cells, KRGE significantly decreased total allogeneic T cell proliferation. Consistent with the effects of TCR stimulation, KRGE reduced the number of CD4+IL-17+ cells and increased the number of CD4+CD25+Foxp3+ cells under the Th17-polarizing condition.

CONCLUSION

KRGE has immunological benefits through the reciprocal regulation of Th17 and Treg cells during CsA-induced immunosuppression.

Impact of ABO Incompatibility on the Development of Acute Antibody-Mediated Rejection in Kidney Transplant Recipients Presensitized to HLA

Whether the coexistence of anti-A/B antibody and donor specific anti-HLA antibody (HLA-DSA) has a synergistic impact on the development of acute antibody-mediated rejection (AAMR) in kidney transplant recipients (KTRs) is unclear. This study includes 92 KTRs who received a kidney from an ABO-incompatible (ABOi) donor or were presensitized to donor HLA (HLAs) and 292 controls (CONT). HLAs was defined as a crossmatch positivity or the presence of HLA-DSA. We compared the incidence of AAMR among ABOi (n = 58), ABOi+HLAs (n = 12), HLAs (n = 22), and CONT (n = 292) groups and evaluated the risk factors and antibody type (anti-A/B vs. HLA-DSA) responsible for AAMR. AAMR developed less frequently in ABOi and CONT than in the ABOi+HLAs or HLAs (P < 0.05 for all); however, there was no difference between the ABOi+HLAs and HLAs groups. AAMR developed more frequently with strong HLA-DSA at baseline; however, high baseline anti-A/B titer did not affect AAMR development. Strong baseline HLA-DSA was an independent predictor for AAMR, however the baseline anti-A/B titer was not. All four AAMR episodes in ABOi+HLAs were positive to HLA-DSA but not to anti-A/B. In conclusion, ABO incompatibility does not increase the risk for AAMR in HLAs KTRs.

Increase of Th17 Cell Phenotype in Kidney Transplant Recipients with Chronic Allograft Dysfunction

This study was performed to determine the association of Th17 cell phenotype with chronic allograft dysfunction in kidney transplant recipients (KTRs). We compared the expression of Th17 cell phenotype in KTRs with chronic allograft dysfunction group (CAD, n = 52) with four control groups (long-term stable KTRs (LTS, n = 67), early stable KTRs (ES, n = 28), end stage renal disease (ESRD, n = 45), and healthy control (HC, n = 26). We also performed in vitro study using human proximal renal tubular epithelial cell line (HPRTEpiC) to evaluate the effect of IL-17 on human renal tubular epithelial cells. The CAD group showed increased percentage of Th17 cells out of CD4+ T cells and also increased proportion of IL-17 producing cells out of effector memory T cells or out of CCR4+CCR6+/CD4+ T cells compared to the LTS group and other control groups. Also, the serum level of IL-17, IL-33, and RAGE, and the expression of IL-1beta, RAGE, and HMGB1 mRNA showed an increase in the CAD group compared to the LTS group. In vitro study revealed that IL-17 increased production of IL-6 and IL-8 and up-regulated profibrotic gene expression such as ACTA-2 and CTGF in HPRTEpiC in a dose-dependent manner, which suggests that IL-17 has a role in the development of renal tubular cell injury. The results of our study may suggest that increase of Th17 cell phenotype could be a marker for the chronic allograft injury; hence there is a need to develop diagnostic and therapeutic tools targeting the Th17 cells pathway.

Decrease of immature B cell and interleukin-10 during early-post-transplant period in renal transplant recipients under tacrolimus based immunosuppression

B lymphocytes are known to play a role in kidney transplantation (KT) outcomes. Here, we evaluated the proportion of B cell subsets before and after KT. Twenty-one patients, who showed stable allograft function without acute rejection in the month following the KT, were included in this study. Peripheral blood samples were obtained from these patients before transplantation as well as 1month after transplantation. Changes in the proportion of B cell subsets after transplantation were investigated using multi-color flow cytometry. The proportion of lymphocytes in the peripheral blood mononuclear cells (PBMCs) and of CD19(+) B cells in the total leukocyte population did not change after KT. Similarly, the proportions of CD19(+)CD24(+) lymphocytes, mature B cells (CD24(Int)CD38(Inter)/CD19(+)), and memory B cells (CD24(+)CD38(-)/CD19(+)) did not change post-KT. However, the proportion of immature B cells (CD24(+)CD38(+)/CD19(+) B cells) decreased significantly after transplantation (P<0.01). The levels of IL-10, and IL-21, and expression of the B cell marker BLNK also decreased significantly after transplantation. Incubation of PBMCs with tacrolimus (0.1, 1, and 10ng/mL) and mycophenolate mofetil (200μg/mL) an immunosuppressant, resulted in significant reduction in the percentage of immature B cells. In contrast, the proportion of memory and mature B cells was not affected. Taken together, these results show that while the total B lymphocyte count and the proportion of memory/mature B cell subsets do not change after KT, the proportion of immature B cells and the associated cytokines that they secrete decrease significantly.

Combined use of rituximab and plasmapheresis pre-transplant increases post-transplant infections in renal transplant recipients with basiliximab induction therapy

INTRODUCTION

We investigated the effect of combined use of rituximab (RTX) and plasmapheresis (PP) pre-transplant on post-transplant infection.

METHODS

A total of 196 patients undergoing living-donor kidney transplantation at Seoul St. Mary's Hospital, all of whom underwent basiliximab induction therapy, were included in the study. They were divided into 3 groups: RTX/PP/intravenous immune globulin (IVIG) (the RPI group; n = 53), RTX monotherapy (the RTX group; n = 14), and control (the CONT group; n = 129). We compared the post-transplant infections in the 3 groups.

RESULTS

The overall prevalence of infection was significantly higher, and the infection-free survival rate was lower, in the RPI group compared with the RTX or CONT groups (P < 0.05). A trend toward more severe bacterial infections was seen in the RPI group compared with the other groups, and fungal infections developed only in the RPI group. After anti-rejection therapy, a significantly higher rate of infection developed in the RPI group than in the other groups (P < 0.05). In addition, the RPI group was an independent risk factor for the development of infection.

CONCLUSION

Our results show that in the setting of basiliximab induction, the use of combined RTX and PP therapy pre-transplant significantly increases the risk for post-transplant infection.

Chronic infection with Pseudomonas aeruginosa in cystic fibrosis: a risk factor for nasal polyposis after lung transplantation

BACKGROUND

Nasal polyposis (NP) is common in cystic fibrosis (CF) patients. The prevalence of the CF phenotype with NP after lung transplantation (LTx) is unknown. Risk factors for the development of NP after LTx are not well described.

METHODS

CF patients with LTx at our center between November 1992 and December 2009 were included. They were regularly investigated with nasal endoscopy and aspiration of sinus secretions with microbiological evaluation. Patients with and without development of NP were compared along the following parameters: gender, age, dF508, diabetes, acute rejection, NP at LTx, and microbiology of the sinuses before and after LTx. A multivariate Cox regression analysis was performed.

RESULTS

The study included 94 patients; 21 were excluded because of incomplete data. Thirty-five (48%) of the remaining 73 patients developed NP. Mean time to diagnosis of NP was 4.2 (2.9-5.6) years after LTx. Prevalence of NP was 11% after the first year and 18%, 33%, and 44% after the first 2, 5, and 10 years, respectively. Patients with posttransplantation NP were younger, had NP before LTx, and were chronically infected with Pseudomonas aeruginosa (PA) in the nose. Multivariate analysis demonstrated that chronic infection with PA was the only significant risk factor for the development of nasal polyps after LTx (hazards ratio, 7.2; 95% confidence interval, 2.1-24.2; P=0.001).

CONCLUSIONS

In contrast to pretransplantation patients, NP is more common after LTx. Development of NP occurs throughout the whole observation time. Chronic sinonasal PA infection seems to be the only significant risk factor for NP after LTx.

Effects of immunosuppressive agents on Th17 cells involved in transplantation

The lymphocyte-derived helper T (Th) cells are critical regulators of the adaptive immune response and are associated with inflammatory disease. The most recently recognized Th-cell lineage, Th17, plays an important role in host defense against extracellular pathogens by secreting the proinflammatory cytokine, interleukin 17, and recruiting reactive oxygen species (ROS)-producing monocytes to the site of infection. However, accumulating evidence has implicated Th17-cell dysregulation as an underlying cause for some immune-related pathogenic conditions, including allograft rejection. Recent studies of human transplant patients have indicated that Th17 cells exhibit resistance to current immunosuppressive therapies that would otherwise prevent allograft rejection. In this review, we will discuss the most current research findings related to Th17-cell function in various kinds of allografts.