TREG Therapy: Hope for the Holy Grail of Kidney Transplantation?

How to improve the long-term survival rate of transplants and transplant recipients is the subject of transplantation research, in which the study of immunosuppressants occupies an important position, while immunosuppressants are the efficacy of anti-rejection reactions on one side and adverse reactions on the other.
inhibitors inhibit the proliferation and function of immune response-related cells (mainly T-cells and B-cells) and reduce the immune response.
Because the mechanism of action of various immunosuppressants is different and the degree of adverse reactions is mostly related to the use of doses, the different targets and key steps for transplant rejection reactions often use a combination of immunosuppressants, which can jointly enhance the immunosuppressive effect, but also reduce the dose of various immunosuppressants and the occurrence of adverse reactions.
immunosuppressants currently used in clinical practice are divided into immuno-induced drugs and maintenance therapy drugs, commonly used immunosuppressants and their effects are shown in Figure 1.
figure 1. Map of the action links of various immunosuppressants: APC is an antigen-presented cell; IL is a lecithin; TCR is a T-cell subject; JAK is Janus kinase; PI3K is phosphatidyl inositol-3-kinase; mTOR is a target protein for mammalian repamycin; CN is calcium-adjusted phosphorus Acidase; MAP kinase is a silk-splitting active protein kinase; IKK is a nucleokine-B kinase inhibitor; NFAT is an activated T-cell nucleokine; AP-1 is an active protein factor; CKD/cyclins is periodic protein-dependent kinase; and IMPDH is a secondary jaundice nucleotide dehydrogenase.
nearly a decade, Treg cell therapy has conducted clinical trials on a range of transplant-related and non-transplant-related adaptations.
Although these trials focused on safety, a core theme of all trials was the heterogeneity of GMP programmes in cell separation, operation, amplification, dosage, specificity and post-drug cell tracking.
there is some consensus on standardization, the reality is that the novelty of Treg cells requires a lot of human research and focus on the optimization and standardization of GMP conditions.
part of the study that wants to make purer cells is based on the idea that the supply-specific TREG is better at treating transplant-effect T-cell responses than multiclonal TREG.
is important to clarify and use this mechanism in humans, as the purity of the product and the degree of isoid antigen specificity may have an impact on the therapeutic effect and the number of infusion cells.
a key advantage of the kidneys is that the living provider has a greater logistical support range, which provides continuous access to fresh feeder antigens, thus providing provider-specific Treg cells.
01, Treg classification due to chronic iso-transplant dysfunction and immunosuppression of long-term side effects have not been fully resolved, transplant tolerance is still the holy grail in the field of organ transplantation.
this point, the increase of regulatory T-cells (Treg cells) in the micro-environment of extrinsic circulation and grafts is considered an important factor in inducing transplant tolerance.
human and mouse polyclonal Treg cells are classically divided into thymus Treg cells (tTreg), extrinsden Treg cells (pTreg) and induced Treg cells (iTreg), and some scholars distinguish between tTreg cells and pTreg cells by the high expression of Helios and Neuropilin-1 (NRP-1) on tTreg cells.
, however, Helios/NRP-1 itself cannot classify tTregs and pTreg cells in humans.
cells in the outer cycle are characterized by CD4 plus, high levels of IL-2 subject α chains (CD25high), low levels of CD127, and in-cell expression fork box P3 transcription factor (FOXP3 plus).
the adoption of new deep immune estypes confirms that the estype is more heterogeneity than originally thought, and that these data vary depending on the type, type, differentiation and micro-environment of Therg cells.
is shown in Figure 2 below.
further differentiation is made by identifying the coercion factor subject, as shown in Figure 3 below.
2. Distinguish CD4-T cells according to the expression levels of FOXP3 and CD45RA to determine the Treg cell sub-group. The diversity of Treg cells and their sub-groups.
(A) showed that Treg cells were divided into different groups based on the expression spectrum of their tendon receptors.
(B) shows a series of in-cell and/or extracellular markers identified on Treg cells, and the possibility of using Th17-like effect cell esotypes and functions in inflammatory micro-environments is a key safety issue.
this is because Th17 cells increase in patients with acute and chronic iso-transplant rejection, which can lead to the deterioration of both conditions.
another way to interact with Treg-Th17 is that both originated initially from Naive CD4 plus cells, but their subsequent differentiation pathways were determined by the presence of IL-6-free conversion growth factor-β (for Treg) or IL-6 (for Th17) in the micro-environment, respectively.
potential of the micro-environment to convert Treg cells into Th17 cells that promote rejection may determine the point in time at which Treg cells are infused.
theory, Treg cell therapy can be proactive (i.e., before the patient has a rejection reaction) or reactive (i.e. given to a patient diagnosed with acute or chronic rejection).
, however, it is not clear whether Treg cells can induce tolerance in micro-environments that have been penetrated by Teffs.
B: Bystander suppression effect Treg cell therapy can be a potential problem, as Treg cells, once activated, can perform their inhibition function in a non-antigen-specific manner.
This effect, known as bystander suppression, was found in genetically modified mouse models, where antigen-specific CD4-CD25-T cells initially needed complementary table contact with TCR-mediated to activate.
, however, once activated, these cells can also inhibit the third-party antigen-specific effects of CD4-T cells.
effect was also shown in models in mice with allogeneic skin transplants.
If this phenomenon does recur in our patients, it may have an impact on regulating antigen-specific rejection while maintaining immunity to new tables of pathogens and potential tumors.
03, TREG representative test A. The TRACT trial recruited 9 people, cell separation using the Clinimacs system, 3-week amplification process using anti-CD3/CD28 antagonists, IL-2, TGF-β, Siromos.
results in purity of 98% CD4-CD25 plus and 80% FOXP3-plus, as well as similar levels of dDMylation.
patients received alemtuzumab treatment on the day of the transplant and on the 2nd day after surgery and maintained the use of MMF and his kemos (30 days to Siromos).
Thetreg cells are then infused on the 60th day.
in the two years reported, there were no cases of opportunity infection caused by cytocytovirus or polybromavirus, and no rejection.
the trial did not report cases of opportgenic infection or rejection after patients receiving new kidney transplants were infused with polyclonal Treg cells.
the B. TASK trial, which focused on the use of multiclosed Treg cells to regulate subclinical inflammation of transplanted kidneys.
this is an important research issue because subclinical inflammation is not diagnosed in a timely manner due to its chronic low-level nature and can lead to delayed allogeneic graft dysfunction.
patients with in-body enlargement of in-body Treg cells, with an average dose of 320 x 106 cells.
2-week amplification: anti-CD3/CD28 antagonists, IL-2, heavy hydrogen glucose treatment.
the company will eventually get a purity of 97% CD4 plus and 93% FOXP3 plus and 0.37% CD8 plus products.
the trial recruited three patients who showed this inflammation in live tissue tests six months after the transplant (Banff i-and t-lt;2).
when patients get Treg cells, they are already taking MMF, thokmos and strong pine dragons.
importantly, from a safety perspective, the trial reported that Treg products did not directly cause SAE and no infection or graft dysfunction was reported during the one-year follow-up period.
, however, a key limitation of the current trial is that the radon signal cannot be detected for 3 months compared to what was not detected for more than 12 months in another trial.
this negates the long-term use of this technology.
were not reported in kidney biopsies 2 weeks and 6 months after infusion.
, it is unclear whether the products of dehydrogenated Treg cells can be migrated to transplants.
addition to this fact, two weeks after infusion, no patients showed an increase in EXPRESSION3 plus in the renal biopsy tissue, and only one patient experienced this at 6 months.
addition, although the technology helps with short-term tracking, it does not provide knowledge about the function of live Treg.
, in kidney transplantation, there was no SAE after infusion of FACS isolated and multiclonal amplified German Treg cells.
test is currently comparing the efficacy of multiclosed and isotrogen-specific Treg cells (NCT02711826).
C. The ONE trial (Germany) is an assessment of whether it is safe and feasible to reshape a patient's immune balance by infusion of autologous naturally regulated T-cells (nTreg) after kidney transplantation, and to gradually reduce lifetime high-dose immunosuppression (with limited efficacy, adverse reactions, high direct and indirect costs), while addressing several key challenges of Treg therapy in useful proof-of-concept disease models, such as simple and reliable manufacturing, the risk of over-immunosuppression, interaction with standard care drugs, and the stability of inflammation.
specific design is shown in Figure 4 below.
4. Clinical trial design participants: live kidney transplant recipients (ONEnTreg13, n=11) and corresponding reference group trials (ONErgt11-CHA, n=9).
interventions: CD4-CD25-FoxP3-nTreg products are injected intravenously with 0.5, 1.0 or 2.5-3.0×106 cell/kg body weight 7 days after kidney transplantation, followed by a gradual reduction of triple immunosuppression to a small dose of tekmos monotherapy until 48 weeks.
results measured: the main clinical and safety endpoints were evaluated by a comprehensive endpoint at week 60 and followed up for further three years.
assessment included the rate of acute rejection confirmed by biopsies, an assessment of injection nTreg-related adverse reactions, and signs of excessive immunosuppression.
end points include the function of allogeneic transplantation, the comprehensive combination of exploratory biomarkers, etc.
results are shown in Figures 5 and 6 and 7.
Figure 5. Main endpoint results Figure 6. In the case of monitoring patients' thokmos levels, the nTreg trial group (switched to monotherapy) gradually reduced immunosuppressive graph 7. Isomorphic kidney transplantation function compared to the reference group (continuous two- or triple-drug treatment). Long-term follow-up Graph 8. Before and after infusion of serum or urine levels of inflammatory cytokines For all patients, the acquisition of 40-50 ml of outer blood two weeks before the kidney transplant can produce nTreg products with sufficient yield, purity and functionality.
three nTreg dose increment groups were free of dose-limiting toxicity.
100% three-year survival rate of allogeneic grafts in the nTreg group and the reference group, with similar clinical and safety characteristics.
8 (73%) of the 11 patients treated with nTregs received stable single-drug immunosuppression, while the control group was still receiving standard secondary or triple drug immunosuppression (P=0.002).
the first in this trial: no signs of inflammatory response.
: No clinical infections with excessive immunosuppression were seen, which was previously assumed to be a safety issue.
authors, Treg cells lose activation and even die within a few days without T-cell stimulation or CD28 stimulation.
, only Treg clones that are stimulated by repeated antigens can maintain their inhibition and expand in the body.
third, the authors observed that the polyclonal T-cells of the infused Treg product changed over time in the body to oligoclonal patterns, indicating a selection process driven by isoid antigens.
Again, replacing anti-CD3/28 multiclonal antibodies with allogeneic antigens in inosometrific produces a biased T-cell-like genealogy within a few days, suggesting that there is a specific immunomodulation effect even after the injection of polyclonal nTregs.
, injections of nTreg only led to a temporary increase in Treg counts.
decrease in circulation after four weeks may be that nTregs focuses on inflamed grafts or lacks long-lasting implants.
, the nTreg group expressed less conventional T-cell activation and natural killer cell maturation, which may indicate how nTreg works in the body.
important to emphasize is that the results of this trial show that nTregs combined with small doses of tekmos monotherapy does not adequately control pre-existing disease-dnogenic memory or effect immune cells.
hypothesis should be studied carefully in subsequent studies.
04, Treg therapy summarizes that there are currently two main ways to make Treg cells: to amplification of Tr in the body