Combined Immunotherapy With Belatacept and BTLA Overexpression Attenuates Acute Rejection Following Kidney Transplantation

Emerging strategies for treating autoimmune disease with genetically modified dendritic cells

Gene editing of living cells has become a crucial tool in medical research, enabling scientists to address fundamental biological questions and develop novel strategies for disease treatment. This technology has particularly revolutionized adoptive transfer cell therapy products, leading to significant advancements in tumor treatment and offering promising outcomes in managing transplant rejection, autoimmune disorders, and inflammatory diseases. While recent clinical trials have demonstrated the safety of tolerogenic dendritic cell (TolDC) immunotherapy, concerns remain regarding its effectiveness. This review aims to discuss the application of gene editing techniques to enhance the tolerance function of dendritic cells (DCs), with a particular focus on preclinical strategies that are currently being investigated to optimize the tolerogenic phenotype and function of DCs. We explore potential approaches for in vitro generation of TolDCs and provide an overview of emerging strategies for modifying DCs. Additionally, we highlight the primary challenges hindering the clinical adoption of TolDC therapeutics and propose future research directions in this field.

Relationship between the microenvironment and survival in kidney transplantation: a bibliometric analysis from 2013 to 2023

Background

Kidney transplantation is considered the most effective treatment for end-stage renal failure. Recent studies have shown that the significance of the immune microenvironment after kidney transplantation in determining prognosis of patients. Therefore, this study aimed to conduct a bibliometric analysis to provide an overview of the knowledge structure and research trends regarding the immune microenvironment and survival in kidney transplantation.

Methods

Our search included relevant publications from 2013 to 2023 retrieved from the Web of Science core repository and finally included 865 articles. To perform the bibliometric analysis, we utilized tools such as VOSviewer, CiteSpace, and the R package "bibliometrix". The analysis focused on various aspects, including country, author, year, topic, reference, and keyword clustering.

Results

Based on the inclusion criteria, a total of 865 articles were found, with a trend of steady increase. China and the United States were the countries with the most publications. Nanjing Medical University was the most productive institution. High-frequency keywords were clustered into 6 areas, including kidney transplantation, transforming growth factor β, macrophage, antibody-mediated rejection, necrosis factor alpha, and dysfunction. Antibody mediated rejection (2019-2023) was the main area of research in recent years.

Conclusion

This groundbreaking bibliometric study comprehensively summarizes the research trends and advances related to the immune microenvironment and survival after kidney transplantation. It identifies recent frontiers of research and highlights promising directions for future studies, potentially offering fresh perspectives to scholars in the field.

Immunopotentiating effects of herb-partitioned moxibustion on the spleens of cyclophosphamide-induced immunosuppressed rats

BACKGROUND

To investigate the effec of the herb-partitioned moxibustion on T-lymphocyte activity in immunosuppressed rats through differential modulation of the immune checkpoint molecules CD28 and CTLA-4.

METHODS

Forty-eight Sprague‒Dawley rats were randomly divided into the normal group (NG), the cyclophosphamide model group (CTX), the herb-partitioned moxibustion group (HPM), the CD28 inhibitor + herb-partitioned moxibustion group (aCD28 + HPM), the CTLA-4 inhibitor + herb-partitioned moxibustion group (aCTLA-4 + HPM), and the levamisole group (LEV) (8 rats per group). The immunosuppression model was prepared using cyclophosphamide. HPM treatments was performed via herb-partitioned moxibustion at 4 acupoints, Zhongwan (CV12), Shenque (CV8), Guanyuan (CV4), and Zusanli (ST36). Subsequently, the moxa floss was made into a conical moxa cone, which was then placed on the herbal cake and ignited. Five consecutive moxibustion strokes were performed daily for 10 consecutive days. In addition to the same moxibustion, each rat in the aCD28 + HPM group was injected intraperitoneally with 0.5 mg/kg of CD28 inhibitor per rat on the first day of treatment, and 100 μL of CTLA-4 inhibitor was injected into the aCTLA-4 + HPM group on Days 1, 4, and 7. For the positive control, levamisole (LEV) was administered by gavage at a dose of 2 mg/kg once daily for 10 days.

RESULTS

Compared with those in CTX model rats, the WBC counts in the HPM and other groups were significantly higher. The immobility time of EPM in the HPM group was significantly lower than that of the CTX group. The HE stainin results also showed that after treatment, the the marginal zone area of the spleen tissue in the HPM increased, the number of lymphatic sheath lymphocytes around the small central artery of the spleen increased, and the amount of red pulp containing a small amount of pigmentation was partially reduced. Compared with those in the CTX group, the serum levels of CD28, CTLA-4, B7-1, and B7-2 were significantly lower, and the levels of α-MSH, TrkB, and BDNF were significantly greater in the HPM group. The results of the flow cytometry assay showed a significant increase in the number of CD8 + T lymphocytes after treatment with HPM or other agents compared to that in the CTX group. The immunofluorescence results showed that the levels of CD28 and CTLA-4 lower in spleen tissues than in control tissues, and the binding ability of CD28 to B7-1 and B7-2 was weakened after treatment with HPM and other treatments compared with CTX rats, PCR for CD28, CTLA-4 and B7-1 showed similar results.

CONCLUSION

In the immunosuppressive rat model induced by cyclophosphamide, HPM upregulated the expression of α-MSH, TrkB, and BDNF, and downregulated the expression of CD28 and CTLA-4, thereby enhancing the activity of CD8+ T lymphocytes, restoring spleen function, improving the immunosuppressive state, restoring immune function, and effectively alleviating depressive symptoms.

Immune Checkpoints in Solid Organ Transplantation

Allogenic graft acceptance is only achieved by life-long immunosuppression, which comes at the cost of significant toxicity. Clinicians face the challenge of adapting the patients' treatments over long periods to lower the risks associated with these toxicities, permanently leveraging the risk of excessive versus insufficient immunosuppression. A major goal and challenge in the field of solid organ transplantation (SOT) is to attain a state of stable immune tolerance specifically towards the grafted organ. The immune system is equipped with a set of inhibitory co-receptors known as immune checkpoints (ICs), which physiologically regulate numerous effector functions. Insufficient regulation through these ICs can lead to autoimmunity and/or immune-mediated toxicity, while excessive expression of ICs induces stable hypo-responsiveness, especially in T cells, a state sometimes referred to as exhaustion. IC blockade has emerged in the last decade as a powerful therapeutic tool against cancer. The opposite action, i.e., subverting IC for the benefit of establishing a state of specific hypo-responsiveness against auto- or allo-antigens, is still in its infancy. In this review, we will summarize the available literature on the role of ICs in SOT and the relevance of ICs with graft acceptance. We will also discuss the possible influence of current immunosuppressive medications on IC functions.

IL-21-producing effector Tfh cells promote B cell alloimmunity in lymph nodes and kidney allografts

Follicular helper T (Tfh) cells have been implicated in controlling rejection after allogeneic kidney transplantation, but the precise subsets, origins, and functions of Tfh cells in this process have not been fully characterized. Here we show that a subset of effector Tfh cells marked by previous IL-21 production is potently induced during allogeneic kidney transplantation and is inhibited by immunosuppressive agents. Single-cell RNA-Seq revealed that these lymph node (LN) effector Tfh cells have transcriptional and clonal overlap with IL-21-producing kidney-infiltrating Tfh cells, implicating common origins and developmental trajectories. To investigate the precise functions of IL-21-producing effector Tfh cells in LNs and allografts, we used a mouse model to selectively eliminate these cells and assessed allogeneic B cell clonal dynamics using a single B cell culture system. We found that IL-21-producing effector Tfh cells were essential for transplant rejection by regulating donor-specific germinal center B cell clonal dynamics both systemically in the draining LN and locally within kidney grafts. Thus, IL-21-producing effector Tfh cells have multifaceted roles in Ab-mediated rejection after kidney transplantation by promoting B cell alloimmunity.

B- and T-lymphocyte attenuator could be a new player in accelerated atherosclerosis associated with chronic kidney disease

BACKGROUND

In chronic kidney disease (CKD), cardiovascular morbi-mortality is higher than in general population. Atherosclerotic cardiovascular disease is accelerated in CKD, but specific CKD-related risk factors for atherosclerosis are unknown.

METHODS

CKD patients from the NEFRONA study were used. We performed mRNA array from blood of patients free from atheroma plaque at baseline, with (n=10) and without (n=10) de novo atherosclerotic plaque development 2 years later. Selected mRNA candidates were validated in a bigger sample (n=148). Validated candidates were investigated in vivo in an experimental model of CKD-accelerated atherosclerosis, and in vitro in murine macrophages.

RESULTS

mRNA array analysis showed 92 up-regulated and 67 down-regulated mRNAs in samples from CKD patients with de novo plaque development. The functional analysis pointed to a paramount role of the immune response. The validation in a bigger sample confirmed that B- and T-lymphocyte co-inhibitory molecule (BTLA) down-regulation was associated with de novo plaque presence after 2 years. However, BTLA down-regulation was not found to be associated with atherosclerotic progression in patients with plaque already present at baseline. In a model of CKD-accelerated atherosclerosis, mRNA and protein expression levels of BTLA were significantly decreased in blood samples and atheroma plaques. Plaques from animals with CKD were bigger, had more infiltration of inflammatory cells, higher expression of IL6 and IL17 and less presence of collagen than plaques from control animals. Incubation of macrophages with rat uremic serum decreased BTLA expression.

CONCLUSIONS

BTLA could be a potential biomarker or therapeutic target for atherosclerosis incidence in CKD patients.

Stimulation of Immune Checkpoint Molecule B and T-Lymphocyte Attenuator Alleviates Experimental Crescentic Glomerulonephritis

SIGNIFICANCE STATEMENT

Treatment of acute, crescentic glomerulonephritis (GN) consists of unspecific and potentially toxic immunosuppression. T cells are central in the pathogenesis of GN, and various checkpoint molecules control their activation. The immune checkpoint molecule B and T-lymphocyte attenuator (BTLA) has shown potential for restraining inflammation in other T-cell-mediated disease models. To investigate its role in GN in a murine model of crescentic nephritis, the authors induced nephrotoxic nephritis in BTLA-deficient mice and wild-type mice. They found that BTLA has a renoprotective role through suppression of local Th1-driven inflammation and expansion of T regulatory cells and that administration of an agonistic anti-BTLA antibody attenuated experimental GN. These findings suggest that antibody-based modulation of BTLA may represent a treatment strategy in human glomerular disease.

BACKGROUND

Modulating T-lymphocytes represents a promising targeted therapeutic option for glomerulonephritis (GN) because these cells mediate damage in various experimental and human GN types. The immune checkpoint molecule B and T-lymphocyte attenuator (BTLA) has shown its potential to restrain inflammation in other T-cell-mediated disease models. Its role in GN, however, has not been investigated.

METHODS

We induced nephrotoxic nephritis (NTN), a mouse model of crescentic GN, in Btla -deficient ( BtlaKO ) mice and wild-type littermate controls and assessed disease severity using functional and histologic parameters at different time points after disease induction. Immunologic changes were comprehensively evaluated by flow cytometry, RNA sequencing, and in vitro assays for dendritic cell and T-cell function. Transfer experiments into Rag1KO mice confirmed the observed in vitro findings. In addition, we evaluated the potential of an agonistic anti-BTLA antibody to treat NTN in vivo .

RESULTS

The BtlaKO mice developed aggravated NTN, driven by an increase of infiltrating renal Th1 cells. Single-cell RNA sequencing showed increased renal T-cell activation and positive regulation of the immune response. Although BTLA-deficient regulatory T cells (Tregs) exhibited preserved suppressive function in vitro and in vivo , BtlaKO T effector cells evaded Treg suppression. Administration of an agonistic anti-BTLA antibody robustly attenuated NTN by suppressing nephritogenic T effector cells and promoting Treg expansion.

CONCLUSIONS

In a model of crescentic GN, BTLA signaling effectively restrained nephritogenic Th1 cells and promoted regulatory T cells. Suppression of T-cell-mediated inflammation by BTLA stimulation may prove relevant for a broad range of conditions involving acute GN.

The Flow Cytometric Analysis of Peripheral Blood Lymphocytes and Expression of HLA II Molecules in Lymphocyte During Acute Rejection After Renal Transplantation

Objective

To investigate the changes in the proportion of peripheral blood lymphocytes and the expression of HLA II molecules in lymphocytes during acute rejection after renal transplantation.

Methods

Thirty-five patients who had undergone renal transplantation were selected. Eighteen patients with clinical and pathological confirmed acute rejection were selected as the test group, and twelve patients without clinical acute rejection symptoms were selected as the control group. Flow cytometry analysis was used to determine the proportion of peripheral blood lymphocytes. The mRNA and protein expression of HLA II molecules on peripheral blood lymphocytes were detected using real-time fluorescence quantification and immunoblotting, respectively.

Results

The proportion of T lymphocytes, B lymphocytes, and CD4CD8 double positive T cells in the Control Group were 67.48% ± 5.35%, 10.82% ± 1.26%, and 0.88% ± 0.06%, respectively, and in the Test Group were 87.52% ± 6.28%, 3.36% ± 0.26%, and 0.34% ± 0.03%, with a significant difference respectively. The mRNA and protein expressions of HLA II molecules of peripheral blood B lymphocytes in the control group were significantly higher that these in the test group.

Conclusion

The proportion of peripheral blood T lymphocytes, B lymphocytes, CD4CD8 double positive T cells, and the expression of HLA II molecules of peripheral blood lymphocytes can all indicate the occurrence of acute renal transplantation rejection, which were exceedingly useful to clinicians in judging the acute rejection of renal transplantation in the early stages.

Porcine anti-human lymphocyte immunoglobulin depletes the lymphocyte population to promote successful kidney transplantation

Introduction

Porcine anti-human lymphocyte immunoglobulin (pALG) has been used in kidney transplantation, but its impacts on the lymphocyte cell pool remain unclear.

Methods

We retrospectively analyzed 12 kidney transplant recipients receiving pALG, and additional recipients receiving rabbit anti-human thymocyte immunoglobulin (rATG), basiliximab, or no induction therapy as a comparison group.

Results

pALG showed high binding affinity to peripheral blood mononuclear cells (PBMCs) after administration, immediately depleting blood lymphocytes; an effect that was weaker than rATG but stronger than basiliximab. Single-cell sequencing analysis showed that pALG mainly influenced T cells and innate immune cells (mononuclear phagocytes and neutrophils). By analyzing immune cell subsets, we found that pALG moderately depleted CD4+T cells, CD8+T cells, regulatory T cells, and NKT cells and mildly inhibited dendritic cells. Serum inflammatory cytokines (IL-2, IL-6) were only moderately increased compared with rATG, which might be beneficial in terms of reducing the risk of untoward immune activation. During 3 months of follow-up, we found that all recipients and transplanted kidneys survived and showed good organ function recovery; there were no cases of rejection and a low rate of complications.

Discussion

In conclusion, pALG acts mainly by moderately depleting T cells and is thus a good candidate for induction therapy for kidney transplant recipients. The immunological features of pALG should be exploited for the development of individually-optimized induction therapies based on the needs of the transplant and the immune status of the patient, which is appropriate for non-high-risk recipients.

Transcriptionally Distinct B Cells Infiltrate Allografts After Kidney Transplantation

BACKGROUND

Following allogeneic kidney transplantation, a substantial proportion of graft loss is attributed to the formation of donor-specific antibodies and antibody-mediated rejection. B cells infiltrate kidney grafts during antibody-mediated rejection; however, the origins, repertoires, and functions of these intrarenal B cells remain elusive.

METHODS

Here, we use murine allogeneic kidney transplant models to study the origins, transcriptional programming and B cell receptor repertoire of intragraft B cells, and in vitro stimulation assays to evaluate the ability of intragraft B cells to promote CD4+ T cell expansion.

RESULTS

B cells infiltrate kidney grafts in settings of allogeneic, but not syngeneic, transplantation. Intragraft B cells have characteristics of activation but are transcriptionally distinct from germinal center B cells and resemble innate-like B cells. B cell receptor sequencing demonstrates that the majority of intragraft B cells do not originate from lymph node germinal center B cells and are largely germline. Class-switched intragraft B cells are rare but can be donor-specific and produce IgG capable of binding to the kidney allograft. Lastly, intrarenal B cells are capable of stimulating naive T cells but have an altered ability to promote T follicular helper cell expansion.

CONCLUSIONS

Together, these data demonstrate that intrarenal B cells during transplant rejection are transcriptionally distinct from lymph node B cells.

Transcriptomic analysis of graft liver provides insight into the immune response of rat liver transplantation

Background

As an “immune-privileged organ”, the liver has higher rates of both spontaneous tolerance and operational tolerance after being transplanted compared with other solid organs. Also, a large number of patients still need to take long-term immunosuppression regimens. Liver transplantation (LT) rejection involves varieties of pathophysiological processes and cell types, and a deeper understanding of LT immune response is urgently needed.

Methods

Homogenic and allogeneic rat LT models were established, and recipient tissue was collected on postoperative day 7. The degree of LT rejection was evaluated by liver pathological changes and liver function. Differentially expressed genes (DEGs) were detected by transcriptome sequencing and confirmed by reverse transcription-polymerase chain reaction. The functional properties of DEGs were characterized by the Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG), and Reactome pathway analyses. The cells infiltrating the graft and recipient spleen and peripheral blood were evaluated by immunofluorescence and flow cytometry.

Result

A total of 1,465 DEGs were screened, including 1,177 up-regulated genes and 288 down-regulated genes. GO enrichment and KEGG pathway analysis indicated that DEGs were involved in several immunobiological processes, including T cell activation, Th1, Th2 and Th17 cell differentiation, cytokine-cytokine receptor interaction and other immune processes. Reactome results showed that PD-1 signaling was enriched. Further research confirmed that mRNA expression of multiple immune cell markers increased and markers of T cell exhaustion significantly changed. Flow cytometry showed that the proportion of Treg decreased, and that of PD-1+CD4+ T cells and PD-1+CD8+ T cells increased in the allogeneic group.

Conclusion

Using an omic approach, we revealed that the development of LT rejection involved multiple immune cells, activation of various immune pathways, and specific alterations of immune checkpoints, which would benefit risk assessment in the clinic and understanding of pathogenesis regarding LT tolerance. Further clinical validations are warranted for our findings.

Activation of the Aryl Hydrocarbon Receptor Ameliorates Acute Rejection of Rat Liver Transplantation by Regulating Treg Proliferation and PD-1 Expression

BACKGROUND

Aryl hydrocarbon receptor (AhR) plays important roles in modulating immune responses. However, the role of AhR in rat liver transplantation (LT) has not been explored.

METHODS

Safety and side effects of N -(3,4-dimethoxycinnamonyl) anthranilic acid (3,4-DAA) and 2-methyl-2H-pyrazole-3-carboxylic acid amide (CH223191) were evaluated. We used optimal doses of 2 drugs, 3,4-DAA, a drug used for mediating AhR activation, and CH223191, antagonist of AhR (3,4-DAA, CH223191, and 3,4-DAA + CH223191), intraperitoneally administered to recipients daily to investigate the role of AhR in the rat LT model. The recipient livers were used to observe the pathological changes, the cells infiltrating the graft, and changes of AhR and programmed death-1 (PD-1) by Western blot, real-time polymerase chain reaction, and immunofluorescence assays. The contents of Foxp3 + and PD-1 + T cells in the recipient spleen and peripheral blood mononuclear cells were evaluated by flow cytometry. In vitro, after isolating CD4 + T cells, they were treated with different AhR ligands to observe the differentiation direction and PD-1 expression level.

RESULTS

The activation of AhR by 3,4-DAA prolonged survival time and ameliorated graft rejection, which were associated with increased expression of AhR and PD-1 in the livers and increased Foxp3 + T cells and PD-1 + T cells in recipient spleens, livers, and peripheral blood mononuclear cells. In vitro, primary T cells incubated with 3,4-DAA mediated increased proportion of Treg and PD-1 + T cells. However, the suppression of AhR with CH223191 reverses these effects, both in the LT model and in vitro.

CONCLUSIONS

Our results indicated that AhR activation might reduce the occurrence of rat acute rejection by increasing the proportion of Treg and the expression of PD-1.

Role of T follicular helper and T follicular regulatory cells in antibody-mediated rejection: new therapeutic targets?

PURPOSE OF REVIEW

Antibody-mediated rejection (AbMR) after solid organ transplantation is tightly controlled by multiple cells of the immune system. Tfh and Tfr cells are essential controllers of antibody responses making them putative targets for therapeutics. However, the mechanisms of how Tfh and Tfr cells regulate B cell and antibody responses are not completely understood. Here, we summarize recent studies elucidating the functions of T follicular helper (Tfh) and T follicular regulatory (Tfr) cells as well as their possible roles in regulating AbMR in solid organ transplantation.

RECENT FINDINGS

New tools have been developed to study the roles of Tfh and Tfr cells in specific disease states, including AbMR after solid organ transplantation. These tools suggest complex roles for Tfh and Tfr cells in controlling antibody responses. Nevertheless, studies in solid organ transplant rejection suggest that Tfh and Tfr cells may be high value targets for therapeutics. However, specific strategies to target these cells are still being investigated.

SUMMARY

AbMR is still a substantial clinical problem that restricts long-term survival after solid organ transplantation. Growing evidence has demonstrated a pivotal role for Tfh and Tfr cells in controlling AbMR. In addition to providing an early indication of rejection as a biomarker, targeting Tfh and Tfr cells as a therapeutic strategy offers new hope for alleviating AbMR.