The balance between memory and regulatory cell populations in kidney transplant recipients with operational tolerance

Donor-reactive memory cells represent a barrier to long-term kidney graft survival. A better understanding of regulatory mechanisms that counterbalance alloreactive memory responses may help to identify patients with operational tolerance. This prospective study investigated the equilibrium between memory T-cell subsets and regulatory T or B cells (Tregs, Bregs) in peripheral blood of kidney transplant recipients with operational tolerance (N = 8), chronic rejection (N = 8), and different immunosuppressive treatment regimens (N = 81). Patients on hemodialysis and healthy individuals served as controls (N = 50). In addition, the expression of Treg- and Breg-associated molecule genes was analyzed. Patients with chronic rejection showed a disrupted memory T-cell composition with a significantly higher frequency of circulating CD8+ terminally differentiated effector memory (TEMRA) T cells than patients with operational tolerance, patients on hemodialysis, or healthy controls (P < 0.001). Low frequency of CD8+ TEMRA and high frequency of Tregs and transitional Bregs were found in operationally tolerant patients. Consequently, operationally tolerant patients showed, as compared to all other transplant recipients with different immunosuppressive regiments, the lowest ratios between CD8+ TEMRA T cells and Tregs or Bregs (for both P < 0.001). Moreover, a specific peripheral blood transcription pattern was found in operationally tolerant patients with an increased expression of Breg- and Treg-associated genes CD22 and FoxP3 and a decreased FcγRIIA/FcγRIIB transcript ratio (for all P < 0.001). In conclusion, monitoring the balance between circulating CD8+ TEMRA T cells and regulatory cell subsets and their transcripts may help to distinguish transplant recipients with operational tolerance from recipients at risk of graft loss.

The Joint Vasculitis Registry in German-speaking countries (GeVas): subgroup analysis of 195 GCA patients

OBJECTIVES

Giant cell arteritis (GCA) is one of the most common forms of vasculitis. There is an abundance of studies which are conducted in a randomised controlled trial setting but limited with respect to cohort size and follow-up time. GeVas is the first large-scale registry for vasculitides in German-speaking countries that enables to evaluate this rare disease. Herein we focus on the subgroup of GCA patients including follow-up data up to one year.

METHODS

GeVas is a prospective, web-based, multicentre registry for the documentation of organ manifestations, outcomes, and therapy regimens in vasculitides. Recruitment started in June 2019. By April 2023, 15 centres were initiated and have started to enrol patients.

RESULTS

After 4 years, 195 GCA-patients were included in the registry, of which 64% were female and 36% were male. The average age was 76 years at the time of recruitment (IQR=69-82). Seventy-nine percent were included in the registry because of a newly diagnosed GCA and 21% because of a relapse. At the first assessment most of the patients (89%) described general symptoms. Thirty-one percent stated ocular symptoms. Cranial symptoms were documented in 78% of the cases. All patients were documented with immunosuppressive treatment at start, of whom 95% received prednisolone, 16% cyclophosphamide, 20% methotrexate, and 48% tocilizumab. After three months 62% and after one year 91% of the patients achieved remission.

CONCLUSIONS

Regarding demographics, clinical manifestations and diagnostics, our study showed a similar composition compared to other studies. However, our data differed in terms of treatment regimens.

The Joint Vasculitis Registry in German-speaking countries (GeVas): subgroup analysis of 266 AAV patients

OBJECTIVES

Prospective long-term observational data on the disease course of anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) were missing in Germany to date. Therefore, the Joint Vasculitis Registry in German-speaking countries (GeVas) has been established to follow the course of patients with AAV. The aim of this study is to present baseline data of patients with newly diagnosed and relapsing AAV enrolled in the GeVas registry.

METHODS

GeVas is a prospective, web-based, multicentre, clinician-driven registry for the documentation of organ manifestations, damage, long-term outcomes, and therapy regimens in various types of vasculitis. Recruitment started in June 2019.

RESULTS

Between June 2019 and October 2022, 266 patients with AAV were included in the GeVas registry: 173 (65%) with new-onset and 93 (35%) with relapsing AAV. One hundred and sixty-two (61%) patients were classified as granulomatosis with polyangiitis (GPA), 66 (25%) as microscopic polyangiitis (MPA), 36 (13%) as eosinophilic granulomatosis with polyangiitis (EGPA), and 2 (1%) as renal limited AAV. The median age was 59 years (51-70 years, IQR), 130 (51%) patients were female. Most patients were ANCA positive (177; 67%) and affected by general symptoms, pulmonary, ear nose throat (ENT), renal and neurological involvement. For induction of remission, the majority of patients received glucocorticoids (247, 93%) in combination with either rituximab (118, 45%) or cyclophosphamide (112, 42%).

CONCLUSIONS

Demographic characteristics are comparable to those in other European countries. Differences were found regarding ANCA status, frequencies of organ manifestations, and therapeutic regimens. The GeVas registry will allow longitudinal observations and prospective outcome measures in AAV.

Sex-specific differences in ICOS+ T helper cell differentiation in systemic lupus erythematosus patients with low disease activity

Systemic lupus erythematosus (SLE) is a sex biased chronic autoimmune disease affecting predominantly females during reproductive ages. Changes in the ratio of inducible costimulatory molecule (ICOS)+ regulatory (Treg) and non-regulatory responder (Tresp) CD4+ T cells proved to be crucial for the occurrence of high disease activity. Here, we investigated how the differentiation of ICOS+CD45RA+CD31+ recent thymic emigrant (RTE) Tresps into CD45RA-CD31- memory Tresps affects the percentages of ICOS+ Tresps within total CD4+ T cells. Three different pathways (pathway 1 via CD45RA-CD31+ memory Tresps, pathway 2 via direct proliferation and pathway 3 via resting mature naïve CD45RA+CD31- (MN) cells) were examined in healthy controls and SLE remission patients separated by sex. In female SLE remission patients, immunosuppressive therapy inhibited the ICOS+ RTE differentiation via CD45RA-CD31+ memory Tresps and direct proliferation, leaving an age-independently increased differentiation into CD45RA-CD31- memory Tresps by conversion of resting MN Tresps compared with healthy controls. Due to exhaustion of this pathway with age, no age-dependent change in the percentages of ICOS+ Tresps within total CD4+ T cells could be found. In contrast, no age-independently increased differentiation could be detected in men due to sufficient immunosuppression of all three pathways. This allowed an age-dependent differentiation of ICOS+ RTE Tresps into CD45RA-CD31- memory Tresps by conversion of resting MN Tresps, resulting in age-dependently increasing percentages of ICOS+ Tresps within total CD4+ T cells. We hypothesize that the sex-specific differential effect of immunosuppression on the differentiation of ICOS+ Tresps may explain the sex- and age-dependent occurrence of high disease activity.

Live-virus serum neutralization after bivalent SARS-CoV-2 mRNA vaccination in hemodialysis patients

The development of bivalent booster vaccines addresses the ongoing evolution of the emerging B.1.1.529 (omicron) variant subtypes that are known to escape vaccine-induced neutralizing antibody response. Little is known about the immunogenicity and reactogenicity of bivalent mRNA vaccines in hemodialysis patients with impaired vaccine response. In this prospective, observational cohort study, we analyzed SARS-CoV-2 anti-S1 IgG, surrogate neutralizing antibodies (SNA), and live-virus neutralization against the SARS-CoV-2 wildtype and the BA.5 variant in 42 hemodialysis patients with and without prior SARS-CoV-2 infection before and after an additional fifth bivalent vaccine dose. Anti-S1 IgG and SNA were significantly higher in hemodialysis patients with prior infection than in patients without infection (p < 0.001 and p < 0.01, respectively). In patients without prior infection, both antibody levels increased, and live-virus neutralizing antibodies against the wildtype and the BA.5 variant were correspondingly significantly higher after bivalent booster vaccination (p < 0.001 for both). Conversely, in patients with prior infection, anti-S1 IgG and SNA did not alter significantly, and bivalent booster vaccination did not induce additional humoral immune response against the SARS-CoV-2 wildtype and the BA.5 variant. Thus, bivalent mRNA vaccines might increase humoral responses in hemodialysis patients without prior infection. Larger clinical trials are needed to help guide vaccination strategies in these immunocompromised individuals.

BA.1/BA.5 Immunogenicity, Reactogenicity, and Disease Activity after COVID-19 Vaccination in Patients with ANCA-Associated Vasculitis: A Prospective Observational Cohort Study

Emerging omicron subtypes with immune escape lead to inadequate vaccine response with breakthrough infections in immunocompromised individuals such as Anti-neutrophil Cytoplasmic Antibody (ANCA)-associated vasculitis (AAV) patients. As AAV is considered an orphan disease, there are still limited data on SARS-CoV-2 vaccination and prospective studies that have focused exclusively on AAV patients are lacking. In addition, there are safety concerns regarding the use of highly immunogenic mRNA vaccines in autoimmune diseases, and further studies investigating reactogenicity are urgently needed. In this prospective observational cohort study, we performed a detailed characterization of neutralizing antibody responses against omicron subtypes and provided a longitudinal assessment of vaccine reactogenicity and AAV disease activity. Different vaccine doses were generally well tolerated and no AAV relapses occurred during follow-up. AAV patients had significantly lower anti-S1 IgG and surrogate-neutralizing antibodies after first, second, and third vaccine doses as compared to healthy controls, respectively. Live-virus neutralization assays against omicron subtypes BA.1 and BA.5 revealed that previous SARS-CoV-2 vaccines result in an inadequate neutralizing immune response in immunocompromised AAV patients. These data demonstrate that new vaccination strategies including adapted mRNA vaccines against epitopes of emerging variants are needed to help protect highly vulnerable individuals such as AAV patients.

Five-year follow-up of a phase I trial of donor-derived modified immune cell infusion in kidney transplantation

Background

The administration of modified immune cells (MIC) before kidney transplantation led to specific immunosuppression against the allogeneic donor and a significant increase in regulatory B lymphocytes. We wondered how this approach affected the continued clinical course of these patients.

Methods

Ten patients from a phase I clinical trial who had received MIC infusions prior to kidney transplantation were retrospectively compared to 15 matched standard-risk recipients. Follow-up was until year five after surgery.

Results

The 10 MIC patients had an excellent clinical course with stable kidney graft function, no donor-specific human leukocyte antigen antibodies (DSA) or acute rejections, and no opportunistic infections. In comparison, a retrospectively matched control group receiving standard immunosuppressive therapy had a higher frequency of DSA (log rank P = 0.046) and more opportunistic infections (log rank P = 0.033). Importantly, MIC patients, and in particular the four patients who had received the highest cell number 7 days before surgery and received low immunosuppression during follow-up, continued to show a lack of anti-donor T lymphocyte reactivity in vitro and high CD19⁺CD24^hiCD38^hi transitional and CD19⁺CD24^hiCD27⁺ memory B lymphocytes until year five after surgery.

Conclusions

MIC infusions together with reduced conventional immunosuppression were associated with good graft function during five years of follow-up, no de novo DSA development and no opportunistic infections. In the future, MIC infusions might contribute to graft protection while reducing the side effects of immunosuppressive therapy. However, this approach needs further validation in direct comparison with prospective controls.

Trial registration

https://clinicaltrials.gov/, identifier NCT02560220 (for the TOL-1 Study). EudraCT Number: 2014-002086-30.

Exhaustion of CD8+ central memory responder T cell differentiation provokes non-melanoma skin cancer in elderly kidney transplant recipients

Introduction

Immunosuppressive therapy prevents graft rejection but increases the risk of non-melanoma skin cancer (NMSC), especially in elderly kidney transplant recipients (KTR).

Methods

In this study, we separately investigated the differentiation of CD8⁺ regulatory T cells (Tregs) and responder T cells (Tresps) between healthy KTR without NMSC, KTR developing de-novo NMSC within two years after the enrolment, and KTR with NMSC at the time of enrolment. Antigen-unexperienced CCR7⁺CD45RA⁺CD31⁺ recent thymic emigrant (RTE) cells differentiate via CD45RA^-CD31⁺ memory (CD31⁺ memory) cells, via resting mature naïve (MN) cells or via direct proliferation into CD45RA^-CD31^- memory (CD31^- memory) cells, consisting of both CCR7⁺CD45RA^- central memory (CM) and CCR7^-CD45RA^- effector memory (EM) cells.

Results

We found that both RTE Treg and Tresp differentiation via CD31⁺ memory Tregs/Tresps was age-independently increased in KTR, who developed de novo NMSC during the follow-up period, causing abundant CM Treg/Tresp production, which may be crucial for cancer immunity. These changes favored a strongly increased CD8⁺ Treg/Tresp ratio, suggesting this ratio as a reliable marker for de-novo NMSC development in KTR. However, with age, this differentiation was replaced by increased conversion of resting MN Tregs/Tresps into CM Tregs/Tresps, which exhausted for Tresps but not for Tregs. In KTR with already existing NMSC at enrolment, differentiation was maintained via conversion and proliferation of resting MN Tregs/Tresps, which however increasingly exhausted with age, especially for Tresps. This resulted in a strong accumulation of terminally differentiated effector memory (TEMRA) Tresps in elderly individuals. Patients with NMSC recurrence showed increased proliferation of resting MN Tregs/Tresps into EM Tregs/Tresps, which tended to exhaust more rapidly, particularly for Tresps, than in patients without NMSC recurrence.

Discussion

In conclusion, we provide evidence that immunosuppressive therapy inhibits differentiation of CD8⁺ Tregs more than that of CD8⁺ Tresps, resulting in an exhausted Tresp profile, thus providing a possible therapeutic approach to improve poor cancer immunity in elderly KTR.

suPAR links a dysregulated immune response to tissue inflammation and sepsis-induced acute kidney injury

Acute kidney injury (AKI) secondary to sepsis results in poor outcomes and conventional kidney function indicators lack diagnostic value. Soluble urokinase plasminogen activator receptor (suPAR) is an innate immune-derived molecule implicated in inflammatory organ damage. We characterized the diagnostic ability of longitudinal serum suPAR levels to discriminate severity and course of sepsis-induced AKI (SI-AKI) in 200 critically ill patients meeting Sepsis-3 criteria. The pathophysiologic relevance of varying suPAR levels in SI-AKI was explored in a polymicrobial sepsis model in WT, (s)uPAR-knockout, and transgenic suPAR-overexpressing mice. At all time points studied, suPAR provided a robust classification of SI-AKI disease severity, with improved prediction of renal replacement therapy (RRT) and mortality compared with established kidney biomarkers. Patients with suPAR levels of greater than 12.7 ng/mL were at highest risk for RRT or death, with an adjusted odds ratio of 7.48 (95% CI, 3.00-18.63). suPAR deficiency protected mice against SI-AKI. suPAR-overexpressing mice exhibited greater kidney damage and poorer survival through inflamed kidneys, accompanied by local upregulation of potent chemoattractants and pronounced kidney T cell infiltration. Hence, suPAR allows for an innate immune-derived and kidney function-independent staging of SI-AKI and offers improved longitudinal risk stratification. suPAR promotes T cell-based kidney inflammation, while suPAR deficiency improves SI-AKI.

Induction of Long-Lasting Regulatory B Lymphocytes by Modified Immune Cells in Kidney Transplant Recipients

BACKGROUND

We recently demonstrated that donor-derived modified immune cells (MICs)-PBMCs that acquire immunosuppressive properties after a brief treatment-induced specific immunosuppression against the allogeneic donor when administered before kidney transplantation. We found up to a 68-fold increase in CD19 + CD24 hi CD38 hi transitional B lymphocytes compared with transplanted controls.

METHODS

Ten patients from a phase 1 clinical trial who had received MIC infusions before kidney transplantation were followed to post-transplant day 1080.

RESULTS

Patients treated with MICs had a favorable clinical course, showing no donor-specific human leukocyte antigen antibodies or acute rejections. The four patients who had received the highest dose of MICs 7 days before surgery and were on reduced immunosuppressive therapy showed an absence of in vitro lymphocyte reactivity against stimulatory donor blood cells, whereas reactivity against third party cells was preserved. In these patients, numbers of transitional B lymphocytes were 75-fold and seven-fold higher than in 12 long-term survivors on minimal immunosuppression and four operationally tolerant patients, respectively ( P <0.001 for both). In addition, we found significantly higher numbers of other regulatory B lymphocyte subsets and a gene expression signature suggestive of operational tolerance in three of four patients. In MIC-treated patients, in vitro lymphocyte reactivity against donor blood cells was restored after B lymphocyte depletion, suggesting a direct pathophysiologic role of regulatory B lymphocytes in donor-specific unresponsiveness.

CONCLUSIONS

These results indicate that donor-specific immunosuppression after MIC infusion is long-lasting and associated with a striking increase in regulatory B lymphocytes. Donor-derived MICs appear to be an immunoregulatory cell population that when administered to recipients before transplantation, may exert a beneficial effect on kidney transplants.

CLINICAL TRIAL REGISTRY NAME AND REGISTRATION NUMBER

MIC Cell Therapy for Individualized Immunosuppression in Living Donor Kidney Transplant Recipients (TOL-1), NCT02560220.

Individualised immunosuppression with intravenously administered donor-derived modified immune cells compared with standard of care in living donor kidney transplantation (TOL-2 Study): protocol for a multicentre, open-label, phase II, randomised controlled trial

INTRODUCTION

Donor-derived modified immune cells (MIC) induced long-term specific immunosuppression against the allogeneic donor in preclinical models of transplantation. In a phase I clinical trial (TOL-1 Study), MIC treatment resulted in a cellular phenotype that was directly and indirectly suppressive to the recipient's immune system allowing for reduction of conventional immunosuppressive therapy. Here, we describe a protocol for a randomised controlled, multicentre phase-IIb clinical trial of individualised immunosuppression with intravenously administered donor MIC compared with standard-of-care (SoC) in living donor kidney transplantation (TOL-2 Study).

METHODS AND ANALYSIS

Sixty-three living donor kidney transplant recipients from six German transplant centres are randomised 2:1 to treatment with MIC (MIC group, N=42) or no treatment with MIC (control arm, N=21). MIC are manufactured from donor peripheral blood mononuclear cells under Good Manufacturing Practice conditions. The primary objective of this trial is to determine the efficacy of MIC treatment together with reduced conventional immunosuppressive therapy in terms of achieving an operational tolerance-like phenotype compared with SoC 12 months after MIC administration. Key secondary endpoints are the number of patient-relevant infections as well as a composite of biopsy-proven acute rejection, graft loss, graft dysfunction or death. Immunosuppressive therapy of MIC-treated patients is reduced during follow-up under an extended immunological monitoring including human leucocyte antigen-antibody testing, and determination of lymphocyte subsets, for example, regulatory B lymphocytes (Breg) and antidonor T cell response. A Data Safety Monitoring Board has been established to allow an independent assessment of safety and efficacy.

ETHICS AND DISSEMINATION

Ethical approval has been provided by the Ethics Committee of the Medical Faculty of the University of Heidelberg, Heidelberg, Germany (AFmu-580/2021, 17 March 2022) and from the Federal Institute for Vaccines and Biomedicines, Paul-Ehrlich-Institute, Langen, Germany (Vorlage-Nr. 4586/02, 21 March 2022). Written informed consent will be obtained from all patients and respective donors prior to enrolment in the study. The results from the TOL-2 Study will be published in peer-reviewed medical journals and will be presented at symposia and scientific meetings.

TRIAL REGISTRATION NUMBER

NCT05365672.

Humoral response to SARS-CoV-2 mRNA vaccination in previous non-responder kidney transplant recipients after short-term withdrawal of mycophenolic acid

Seroconversion rates after COVID-19 vaccination are significantly lower in kidney transplant recipients compared to healthy cohorts. Adaptive immunization strategies are needed to protect these patients from COVID-19. In this prospective observational cohort study, we enrolled 76 kidney transplant recipients with no seroresponse after at least three COVID-19 vaccinations to receive an additional mRNA-1273 vaccination (full dose, 100 μg). Mycophenolic acid was withdrawn in 43 selected patients 5–7 days prior to vaccination and remained paused for 4 additional weeks after vaccination. SARS-CoV-2-specific antibodies and neutralization of the delta and omicron variants were determined using a live-virus assay 4 weeks after vaccination. In patients with temporary mycophenolic acid withdrawal, donor-specific anti-HLA antibodies and donor-derived cell-free DNA were monitored before withdrawal and at follow-up. SARS-CoV-2 specific antibodies significantly increased in kidney transplant recipients after additional COVID-19 vaccination. The effect was most pronounced in individuals in whom mycophenolic acid was withdrawn during vaccination. Higher SARS-CoV-2 specific antibody titers were associated with better neutralization of SARS-CoV-2 delta and omicron variants. In patients with short-term withdrawal of mycophenolic acid, graft function and donor-derived cell-free DNA remained stable. No acute rejection episode occurred during short-term follow-up. However, resurgence of prior anti-HLA donor-specific antibodies was detected in 7 patients.

Neutralizing antibody response against the B.1.617.2 (delta) and the B.1.1.529 (omicron) variants after a third mRNA SARS-CoV-2 vaccine dose in kidney transplant recipients

Seroconversion after COVID-19 vaccination is impaired in kidney transplant recipients. Emerging variants of concern such as the B.1.617.2 (delta) and the B.1.1.529 (omicron) variants pose an increasing threat to these patients. In this observational cohort study, we measured anti-S1 IgG, surrogate neutralizing, and anti-receptor-binding domain antibodies three weeks after a third mRNA vaccine dose in 49 kidney transplant recipients and compared results to 25 age-matched healthy controls. In addition, vaccine-induced neutralization of SARS-CoV-2 wild-type, the B.1.617.2 (delta), and the B.1.1.529 (omicron) variants was assessed using a live-virus assay. After a third vaccine dose, anti-S1 IgG, surrogate neutralizing, and anti-receptor-binding domain antibodies were significantly lower in kidney transplant recipients compared to healthy controls. Only 29/49 (59%) sera of kidney transplant recipients contained neutralizing antibodies against the SARS-CoV-2 wild-type or the B.1.617.2 (delta) variant and neutralization titers were significantly reduced compared to healthy controls (p < 0.001). Vaccine-induced cross-neutralization of the B.1.1.529 (omicron) variants was detectable in 15/35 (43%) kidney transplant recipients with seropositivity for anti-S1 IgG, surrogate neutralizing, and/or anti-RBD antibodies. Neutralization of the B.1.1.529 (omicron) variants was significantly reduced compared to neutralization of SARS-CoV-2 wild-type or the B.1.617.2 (delta) variant for both, kidney transplant recipients and healthy controls (p < .001 for all).

AB0622 The Joint Vasculitis Registry in German-speaking countries (GeVas) – subgroup analysis of 113 GPA-patients

Background

Granulomatosis with polyangiitis (GPA) is the second most frequent vasculitis in Germany with an annual incidence of 34 per million and a prevalence of 210 per million [1]. GPA is characterized by its chronic course, frequent relapses, significant overall morbidity and mortality, and substantial socio-economic impact. Multiorgan involvement affecting the respiratory tract, kidney, and other organs is common. Limited variants also occur [2]. So far, prospective long-term observational data on the disease course of GPA are missing in Germany. Therefore, the Joint Vasculitis Registry in German-speaking countries (GeVas) has been established to follow the course of patients recently diagnosed with vasculitis or a change of their treatment due to a relapse (inception cohort). The GeVas registry allows long-term follow-up of a substantial cohort of vasculitis patients in a multicenter setting.

Objectives

To present the first data on the follow-up of newly diagnosed and relapsing GPA enrolled in the GeVas registry.

Methods

GeVas is a prospective, web-based, multicenter, clinician-driven registry for the documentation of organ manifestations, damage, long-term outcomes, and therapy regimens in various types of vasculitis. Recruitment started in June 2019. By January 2022, 17 centers in Germany were initiated and started enrolling patients. Meanwhile, more than 350 patients have been documented in the registry. Sites in Austria and the German-speaking cantons of Switzerland will be integrated soon [3].

Results

By mid-October 2021, the participating centers included 113 patients with GPA. The majority of patients were PR3-ANCA positive and affected by general symptoms, ENT, lung, renal, and neurological involvement. Patients commonly received cyclophosphamide or rituximab in combination with glucocorticoids for the induction of remission. Fewer patients received methotrexate or other immunosuppressants. Patient characteristics and therapy are summarized in Table 1.

Table 1.

Patient characteristics (n = 113). *Unless otherwise specified.

CategoryFeaturen (%)*AgeAge (years); median [range]60 [51 - 70]GenderMale61 (54.0)Female52 (46.0)Reason for inclusion in the registryNewly diagnosed vasculitis57 (51.4)Relapse56 (49.6)ANCA statusPR3-ANCA99 (87.6)MPO-ANCA4 (3.6)ANCA negative9 (7.9)Organ manifestationGeneral symptoms86 (76.1)ENT69 (61.1)Lung/chest66 (58.4)Renal35 (31.0)Cardiovascular7 (6.2)GI3 (2.7)Neurological27 (23.9)TherapyGlucocorticoid102 (90.3)Rituximab56 (49.6)Cyclophosphamide37 (32.7)Methotrexate and other immunosuppressants, respectively26 (23.0) and 19 (16.8), respectively

Conclusion

Here, we present the first interim analysis of the GeVas registry. Clinical manifestations of GPA reported herein show less frequent renal involvement in comparison with a recent report from another European registry (POLVAS) and an UK study [4, 5]. This is potentially related to the predominance of recruiting rheumatology centers thus far. By contrast, respiratory tract involvement is more frequent and PR3-ANCA less common in Japan [5]. Further data are prospectively documented and a follow up analysis is in progress.

References

[1]Hellmich B, et al. New insights into the epidemiology of ANCA-associated vasculitides in Germany: results from a claims data study. Rheumatology 2021;60:4868-73.

[2]Kitching AR, et al. ANCA-associated vasculitis. Nat Rev Dis Primers 2020;6:71.

[3]Iking-Konert C, et al. The Joint Vasculitis Registry in German-speaking countries (GeVas) – a prospective, multicenter registry for the follow-up of long-term outcomes in vasculitis. BMC Rheumatol 2021;5:40.

[4]Wójcik K, et al. Clinical characteristics of Polish patients with ANCA-asscoiated vasculitides – retrospective analysis of POLVAS registry. Clin Rheumatol 2019;38:2553-63.

[5]Furuta S, et al. Comparison of the phenotype and outcome of granulomatosis with polyangiitis between UK and Japanese cohorts. J Rheumatol 2017;44:216-22.

Acknowledgements

GeVas was supported by unrestricted grants by: DGRh, John Grube Foundation, Vifor and Roche Pharma

Disclosure of Interests

Sabrina Arnold: None declared, Pia Wallmeier: None declared, Fabian Schubach: None declared, Gabriele Ihorst: None declared, Peer Aries: None declared, Raoul Bergner Consultant of: VIFOR, Jan Philip Bremer: None declared, Norman Görl: None declared, Bernhard Hellmich: None declared, Jörg Henes: None declared, Bimba Hoyer: None declared, Antje Kangowski: None declared, Ina Kötter: None declared, Claudia Metzler: None declared, Ulf Müller-Ladner: None declared, Matthias Schaier: None declared, Ulf Schönermark: None declared, Jens Thiel: None declared, Leonore Unger: None declared, Nils Venhoff Speakers bureau: Roche and Vifor: speaker honoraries, Consultant of: Roche and Vifor: advisory boards, Grant/research support from: John-Grube Research Award 2021, Julia Weinmann-Menke: None declared, Jana Petersen: None declared, Christof Iking-Konert Speakers bureau: Lecture fees from: Chugai, GSK, Roche, and Vifor, Consultant of: Consulting fees from: Chugai, GSK, Roche, and Vifor, Grant/research support from: Research grants for GeVas: Roche, Vifor, DGRh, John Grube Foundation, Peter Lamprecht Speakers bureau: Chugai, GSK, Roche, and Vifor, Consultant of: Chugai, GSK, Roche, and Vifor, Grant/research support from: DGRh, John Grube Foundation, Roche, and Vifor

POS0800 THE JOINT VASCULITIS REGISTRY IN GERMAN-SPEAKING COUNTRIES (GeVas) – SUBGROUP ANALYSIS OF 131 GCA-PATIENTS REFERENCES:

Background

The most frequent form of vasculitis in elderly people is giant cell arteritis (GCA) with an annual incidence rate less than 10 per 100,000 persons over the age of 50. Like most vasculitides, GCA is characterized by chronicity and relapses, leading to significant overall morbidity and higher mortality in a subset of patients with aortic involvement and dissection. Most studies carried out so far have been retrospective, used monocentric study designs and small patient cohorts. Therefore, the Joint Vasculitis Registry in German-speaking countries (GeVas) has been established to record patients, who have been recently diagnosed with vasculitis or who have changed their treatment due to a relapse (inception cohort). The GeVas-Registry allows a long-term follow-up of a substantial cohort of vasculitis patients in a prospective and multicenter manner.

Objectives

To describe the subgroup of GCA and its characteristics within the GeVas registry.

Methods

GeVas is a prospective, web-based, multicenter, clinician-driven registry for the documentation of organ manifestations, damage, long-term outcomes, and therapy regimens in various types of vasculitis. Recruitment started in June 2019. By January 2022, 17 centers in Germany were initiated and have begun enrolling patients. Meanwhile, more than 350 patients have been documented in the registry. Sites in Austria and the German-speaking cantons of Switzerland will be integrated soon (1).

Results

By mid-October 2021, the participating centers recruited 131 GCA patients into the registry. 21.7% of patients (n=28) were enrolled in the registry due to relapse, and 78.3% (n=101) due to a first-time diagnosis. In accordance with long-standing epidemiology data, the majority of patients (67,2%), were female (n=88), and 32.8% (n=43) were male. Mean age was 74 years (max. 92y, min. 52y). The most frequently recorded organ manifestations in GCA patients addressed cranial and ophthalmic symptoms, and the cardiovascular system. However, vascular lung/chest involvement was also observed in 3% of cases (n=4). Out of the 131 patients, 97.7% (n=128) received immunosuppressive therapy, three refused to take any medication. An equal number of patients were treated with glucocorticoid (GC) therapy. While about two equal parts were treated by stable long term oral GC therapy (47,7%, n=62) or by i.v. pulse therapy followed by tapering (49,2%, n=64), only about 2.3% (n=3) were treated by oral GC therapy with intermittent i.v. pulses. 48.5% (n=63) of patients received tocilizumab as additional immunosuppressive therapy, 19.2% (n=25) methotrexate, and 18.5% (n=24) cyclophosphamide i.v. pulses.

Conclusion

In June 2019, we successfully established the prospective multicenter vasculitis registry GeVAS. It describes the first systematically recorded prospective GCA cohort in German-speaking countries. Its characteristics correspond to those that can be expected from the literature, with some unexpected finding e.g. the high proportion of patients treated with cyclosphosphamid, probably reflecting a sicker patient population with e.g. aortic or central nervous involvement. After 2.5 years of follow-up documentation, the first long-term results will be systematically evaluated and interpreted. The newly acquired data on disease manifestation, diagnostics and therapy regimens will provide important insights into the treatment of GCA patients in Germany and may generate further research goals.

References

Trial registration: German Clinical Trials Register (Deutsches Register Klinischer Studien): DRKS00011866. Registered 10 May 2019. 3

[1]C Iking-Konert; P Wallmeier; S Arnold; S Adler; K de Groot; B Hellmich; B Hoyer; K Holl-Ulrich; Ihorst; M Kaufmann; I Kötter; U Müller-Ladner; T Magnus; J. Rech; H. Schulze-Koops; N. Venhoff; T. Wiech; P. Villiger; F. Schubach; P. Lamprecht. The Joint Vasculitis Registry in German-speaking countries (GeVas) – a prospective, multicenter registry for the follow-up of long-term outcomes in vasculitis. BMC Rheumatol. 2021 Jul 31;5(1):40. doi: 10.1186/s41927-021-00206-2.

Acknowledgements

GeVas was supported by unrestricted grants by: DGRh, John Grube Foundation, Vifor and Roche Pharma

Disclosure of Interests

Pia Wallmeier: None declared, Sabrina Arnold: None declared, Fabian Schubach: None declared, Gabriele Ihorst: None declared, Peer Aries: None declared, Raoul Bergner Consultant of: Advisory Board VIFOR, Grant/research support from: John-Grube Research Award 2021, Jan Philip Bremer: None declared, Norman Görl: None declared, Bernhard Hellmich: None declared, Jörg Henes: None declared, Bimba Hoyer: None declared, Antje Kangowski: None declared, Ina Kötter: None declared, Tim Magnus: None declared, Claudia Metzler: None declared, Ulf Müller-Ladner: None declared, Matthias Schaier: None declared, Ulf Schönermark: None declared, Jens Thiel: None declared, Leonore Unger: None declared, Nils Venhoff Speakers bureau: Roche and Vifor, Consultant of: Roche and Vifor, Grant/research support from: John-Grube Research Award 2021, Julia Weinmann-Menke: None declared, Jana Petersen: None declared, Peter Lamprecht Speakers bureau: Lecture fees from: Chugai, GSK, Roche, Consultant of: Consulting & lecture fees from: Chugai, GSK, Roche, and Vifor., Grant/research support from: Research grants for GeVas: DGRh, John Grube Foundation, Roche, and Vifor, Christof Iking-Konert Speakers bureau: lecture fees from: Chugai, GSK, Roche, and Vifor., Consultant of: Consulting fees from: Chugai, GSK, Roche, and Vifor., Grant/research support from: Research grants for GeVas: DGRh, John Grube Foundation, Roche, and Vifor;

Chronic Kidney Failure Provokes the Enrichment of Terminally Differentiated CD8+ T Cells, Impairing Cytotoxic Mechanisms After Kidney Transplantation

Chronic kidney failure (KF) provokes the development of immune senescent CD8⁺ cytotoxic T cells, affecting the occurrence of graft rejection, viral infections, and malignancies after kidney transplantation. In this study, we analyzed the impact of KF, subsequent dialysis treatment, and kidney transplantation on the differentiation of CD8⁺CD31⁺CD45RA⁺CCR7⁺ recent thymic emigrant (CCR7⁺ RTE) Tregs/Tresps into CD8⁺CD31^-CD45RA^- memory (CD31^- memory) Tregs/Tresps and its effect on the release of cytokines, Fas receptor, Fas ligand as well as cytotoxic mediators by naïve, central memory (CM), effector memory (EM), and terminally differentiated effector memory (TEMRA) Tresps. We found that normal age-dependent differentiation of CD8⁺ Tregs/Tresps generally differs in the way that TEMRA cells only arise in Tresps. Compared to healthy controls, KF patients revealed an age-independently decreased frequency of CCR7⁺ RTE Tregs/Tresps, but increased frequencies of CCR7⁺ MN Tregs/Tresps and CD31^- memory Tregs/Tresps, suggesting an increased differentiation via CD31⁺CD45RA^- memory (CD31⁺ memory) Tregs/Tresps into CD31^- memory Tregs/Tresps. Intensified differentiation via CD31⁺ memory Tresps increased the emergence of apoptosis-resistant CM Tresps with strong Fas ligand-mediated cytotoxicity. CCR7⁺ RTE Tresp proliferation generated TEMRA Tresps, secreting high levels of cytotoxic mediators. In dialysis and transplant patients, CD31⁺ TEMRA Tregs/Tresps accumulated, proposing an impaired CCR7⁺ RTE Treg/Tresp differentiation via CD31⁺ memory Tregs/Tresps into CD31^- memory Tregs/Tresps. Increased percentages of CD31^- TEMRA Tresps, but not of CD31^- TEMRA Tregs, were observed in all patient groups, indicating impaired proliferation of CCR7⁺ RTE Tresps, but not of CCR7⁺ RTE Tregs, into CD31^- memory Tregs/Tresps. In transplant patients, CCR7⁺ RTE Tregs accumulated, while frequencies of CCR7⁺ RTE Tresps were decreased, suggesting that the immunosuppressive therapy only prevented excessive CCR7⁺ RTE Treg differentiation but not that of CCR7⁺ RTE Tresps. Presumably, this caused the accumulation of TEMRA Tresps with decreased release of cytotoxic mediators, such as perforin. In conclusion, we propose that chronic KF affects both the differentiation of CD8⁺ Tregs and CD8⁺ Tresps. However, the immunosuppressive therapy after transplantation may successfully prevent excessive Treg differentiation, but not as suffciently that of Tresps. Therefore, the risk for graft rejection may be reduced, while the susceptibility for infections and malignancies may be increased in these patients.

Impaired Neutralizing Antibody Activity against B.1.617.2 (Delta) after Anti-SARS-CoV-2 Vaccination in Patients Receiving Anti-CD20 Therapy

Background: To characterize humoral response after standard anti-SARS-CoV-2 vaccination in Rituximab-treated patients and to determine the optimal time point after last Rituximab treatment for appropriate immunization. Methods: Sixty-four patients who received Rituximab within the last seven years prior to the first anti-SARS-CoV-2 vaccination were recruited in a prospective observational study. Anti-S1 IgG, SARS-CoV-2 specific neutralization, and various SARS-CoV-2 target antibodies were determined. A live virus assay was used to assess neutralizing antibody activity against B.1.617.2 (delta). In Rituximab-treated patients, CD19+ peripheral B-cells were quantified using flow cytometry. Results: After second vaccination, all antibodies were significantly reduced compared to healthy controls. Neutralizing antibody activity against B.1.617.2 (delta) was detectable with a median (IQR) ID50 of 0 (0−1:20) compared to 1:320 (1:160−1:320) in healthy controls (for all p < 0.001). Longer time period since last Rituximab administration correlated with higher anti-SARS-CoV-2 antibody levels and a stronger neutralization of B.1.617.2 (delta). With one exception, only patients with a CD19+ cell proportion ≥ 1% had detectable neutralizing antibodies. Conclusion: Our data indicate that a reconstitution of the B-cell population to >1% seems crucial in developing neutralizing antibodies against SARS-CoV-2. We suggest that anti-SARS-CoV-2 vaccination should be administered at least 8−12 months after the last Rituximab treatment for sufficient humoral responses.

Neutralizing Antibody Activity Against the B.1.617.2 (delta) Variant Before and After a Third BNT162b2 Vaccine Dose in Hemodialysis Patients

Hemodialysis patients are at high risk for severe COVID-19, and impaired seroconversion rates have been demonstrated after COVID-19 vaccination. Humoral immunity wanes over time and variants of concern with immune escape are posing an increasing threat. Little is known about protection against the B.1.617.2 (delta) variant of concern in hemodialysis patients before and after third vaccination. We determined anti-S1 IgG, surrogate neutralizing, and IgG antibodies against different SARS-CoV-2 epitopes in 84 hemodialysis patients directly before and three weeks after a third vaccine dose with BNT162b2. Third vaccination was performed after a median (IQR) of 119 (109–165) days after second vaccination. In addition, neutralizing activity against the B.1.617.2 (delta) variant was assessed in 31 seroconverted hemodialysis patients before and after third vaccination. Triple seropositivity for anti-S1 IgG, surrogate neutralizing, and anti-RBD antibodies increased from 31/84 (37%) dialysis patients after second to 80/84 (95%) after third vaccination. Neutralizing activity against the B.1.617.2 (delta) variant was significantly higher after third vaccination with a median (IQR) ID₅₀ of 1:320 (1:160–1:1280) compared with 1:20 (0–1:40) before a third vaccine dose (P<0.001). The anti-S1 IgG index showed the strongest correlation with the ID₅₀ against the B.1.617.2 (delta) variant determined by live virus neutralization (r=0.91). We demonstrate low neutralizing activity against the B.1.617.2 (delta) variant in dialysis patients four months after standard two-dose vaccination but a substantial increase after a third vaccine dose. Booster vaccination(s) should be considered earlier than 6 months after the second vaccine dose in immunocompromised individuals.

Neutralizing antibody activity against the B.1.617.2 (delta) variant 8 months after two-dose vaccination with BNT162b2 in health care workers

Objectives

Methods

Results

Discussion

Living Donor Kidney Transplantation in Patients With Donor-Specific HLA Antibodies After Desensitization With Immunoadsorption

Due to the current organ shortage, living donor kidney transplantation is increasingly performed across HLA (human leukocyte antigen) or ABO antibody barriers. There is still uncertainty about the risk of antibody-mediated rejection (AMR) episodes, which may limit long-term graft survival. From March 2007 to December 2016, 58 sensitized living donor kidney transplant candidates were identified and 38 patients eventually included in the study: 36 patients (95%) had pre-transplant and pre-desensitization Luminex-detected donor-specific HLA antibodies (DSA), and 17/36 patients (47%) in addition had a positive crossmatch result. Two patients had no detectable DSA but a positive CDC B-cell crossmatch result. Patients were treated with pre- and post-transplant apheresis and powerful immunosuppression including the anti-CD20 antibody rituximab (N = 36) in combination with thymoglobulin (N = 20) or anti-IL2 receptor antibody (N = 18). The results of the 38 successfully desensitized and transplanted patients were retrospectively compared to the results of 76 matched standard-risk recipients. Desensitized patients showed patient and graft survival rates similar to that of standard-risk recipients (P = 0.55 and P = 0.16, respectively). There was a trend toward reduced death-censored graft survival in desensitized patients (P = 0.053) which, however, disappeared when the 34 patients who were transplanted after introduction of sensitive Luminex testing were analyzed (P = 0.43). The incidence of rejection episodes without borderline changes were in desensitized patients with 21% similar to the 18% in standard-risk patients (P = 0.74). Thirty-six patients had pre-transplant HLA class I and/or II DSA that were reduced by 85 and 81%, respectively, during pre-transplant desensitization (P < 0.001 for both). On day 360 after transplantation, 20 of 36 (56%) patients had lost their DSA. The overall AMR rate was 6% in these patients, but as high as 60% in 5 (14%) patients with persistent and de novo DSA during year 1; 2 (40%) of whom lost their graft due to AMR. Eleven (31%) patients with persistent DSA but without de novo DSA had an AMR rate of 18% without graft loss while one patient lost her graft without signs of AMR. Our desensitization protocol for pre-sensitized living donor kidney transplant recipients with DSA resulted in good graft outcomes with side effects and rejection rates similar to that of standard-risk recipients. Adequate patient selection prior to transplantation and frequent immunological monitoring thereafter is critical to minimize rejection episodes and subsequent graft loss.

Neutralization of SARS-CoV-2 Variants of Concern in Kidney Transplant Recipients after Standard COVID-19 Vaccination

BACKGROUND AND OBJECTIVES

Antibody response after severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccination is impaired in kidney transplant recipients. Emerging variants, such as B.1.617.2 (δ), are of particular concern because of their higher transmissibility and partial immune escape. Little is known about protection against these variants in immunocompromised patients.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

In this prospective two-center study, antispike 1 IgG and surrogate neutralizing antibodies were measured in 173 kidney transplant recipients and 166 healthy controls with different vaccination schedules. In addition, different SARS-CoV-2 epitope antibodies from 135 vaccinated kidney transplant recipients were compared with antibodies in 25 matched healthy controls after second vaccination. In 36 kidney transplant recipients with seroconversion, neutralization against B.1.1.7 (α), B.1.351 (β), and B.1.617.2 (δ) was determined on VeroE6 cells and compared with neutralization in 25 healthy controls.

RESULTS

Kidney transplant recipients had significantly lower seroconversion rates compared with healthy controls. After the second vaccination, antispike 1, antireceptor-binding domain, and surrogate neutralizing antibodies were detectable in 30%, 27%, and 24% of kidney transplant recipients, respectively. This compares with 100%, 96%, and 100% in healthy controls, respectively (P<0.001). Neutralization against B.1.1.7 was detectable in all kidney transplant recipients with seroconversion, with a median serum dilution that reduces infection of cells by 50% of 80 (interquartile range, 80-320). In contrast, only 23 of 36 (64%) and 24 of 36 (67%) kidney transplant recipients showed neutralization against B.1.351 and B.1.617.2, respectively, with median serum dilutions that reduce infection of cells by 50% of 20 (interquartile range, 0-40) and 20 (interquartile range, 0-40), respectively. Neutralization against different variants was significantly higher in healthy controls (P<0.001), with all patients showing neutralization against all tested variants.

CONCLUSIONS

Seroconverted kidney transplant recipients show impaired neutralization against emerging variants of concern after standard two-dose vaccination.

CLINICAL TRIAL REGISTRY NAME AND REGISTRATION NUMBER

Observational study to assess the SARS-CoV-2 specific immune response in kidney transplant recipients (COVID-19 related immune response), DRKS00024668.

Humoral Responses to Single-Dose BNT162b2 mRNA Vaccination in Dialysis Patients Previously Infected With SARS-CoV-2

Seroconversion rates following infection and vaccination are lower in dialysis patients compared to healthy controls. There is an urgent need for the characterization of humoral responses and success of a single-dose SARS-CoV-2 vaccination in previously infected dialysis patients. We performed a dual-center cohort study comparing three different groups: 25 unvaccinated hemodialysis patients after PCR-confirmed COVID-19 (Group 1), 43 hemodialysis patients after two-time BNT162b2 vaccination without prior SARS-CoV-2 infection (Group 2), and 13 single-dose vaccinated hemodialysis patients with prior SARS-CoV-2 infection (Group 3). Group 3 consists of seven patients from Group 1 and 6 additional patients with sera only available after single-dose vaccination. Anti-S1 IgG, neutralizing antibodies, and antibodies against various SARS-CoV-2 protein epitopes were measured 3 weeks after the first and 3 weeks after the second vaccination in patients without prior SARS-CoV-2 infection, 6 weeks after the onset of COVID-19 in unvaccinated patients, and 3 weeks after single-dose vaccination in patients with prior SARS-CoV-2 infection, respectively. Unvaccinated patients after COVID-19 showed a significantly higher neutralizing antibody capacity than two-time vaccinated patients without prior COVID-19 [median (IQR) percent inhibition 88.0 (71.5-95.5) vs. 50.7 (26.4-81.0); P = 0.018]. After one single vaccine dose, previously infected individuals generated 15- to 34-fold higher levels of anti-S1 IgG than age- and dialysis vintage-matched unvaccinated patients after infection or two-time vaccinated patients without prior SARS-CoV-2 infection with a median (IQR) index of 274 (151-791) compared to 18 (8-41) and 8 (1-21) (for both P < 0.001). With a median (IQR) percent inhibition of 97.6 (97.2-98.9), the neutralizing capacity of SARS-CoV-2 antibodies was significantly higher in single-dose vaccinated patients with prior SARS-CoV-2 infection compared to other groups (for both P < 0.01). Bead-based analysis showed high antibody reactivity against various SARS-CoV-2 spike protein epitopes after single-dose vaccination in previously infected patients. In conclusion, single-dose vaccination in previously infected dialysis patients induced a strong and broad antibody reactivity against various SARS-CoV-2 spike protein epitopes with high neutralizing capacity.

Heterologous ChAdOx1 nCoV-19/BNT162b2 Prime-Boost Vaccination Induces Strong Humoral Responses among Health Care Workers

Despite limited data on safety and immunogenicity, heterologous prime-boost vaccination is currently recommended for individuals with ChAdOx1 nCoV-19 prime immunization in certain age groups. In this prospective, single-center study we included 166 health care workers from Heidelberg University Hospital who received either heterologous ChAdOx1 nCoV-19/BNT162b2, homologous BNT162b2 or homologous ChAdOx1 nCoV-19 vaccination between December 2020 and May 2021. We measured anti-S1 IgG, SARS-CoV-2 specific neutralizing antibodies, and antibodies against different SARS-CoV-2 fragments 0-3 days before and 19-21 days after boost vaccination. Before boost, 55/70 (79%) ChAdOx1 nCoV-19-primed compared with 44/45 (98%) BNT162b2-primed individuals showed positive anti-S1 IgG with a median (IQR) anti-S1 IgG index of 1.95 (1.05-2.99) compared to 9.38 (6.26-17.12). SARS-CoV-2 neutralizing antibodies exceeded the threshold in 24/70 (34%) of ChAdOx1 nCoV-19-primed and 43/45 (96%) of BNT162b2-primed individuals. After boosting dose, median (IQR) anti-S1 IgG index in heterologous ChAdOx1 nCoV-19/BNT162b2 vaccinees was 116.2 (61.84-170), compared to 13.09 (7.03-29.02) in homologous ChAdOx1 nCoV-19 and 145.5 (100-291.1) in homologous BNT162b2 vaccinees. All boosted vaccinees exceeded the threshold for neutralization, irrespective of their vaccination scheme. Vaccination was well-tolerated overall. We show that heterologous ChAdOx1 nCoV-19/BNT162b2 vaccination is safe and induces a strong and broad humoral response in healthy individuals.

Cyclophosphamide induction dose and outcomes in ANCA-associated vasculitis with renal involvement: A comparative cohort study

ABSTRACT

Treatment of ANCA-associated vasculitis (AAV) improved over the last decades but disease-unspecific agents such as cyclophosphamide are still associated with serious adverse events, including high rates of infectious complications and malignancy with increased mortality.In this comparative cohort study, we included 121 AAV patients with renal involvement from 2 German vasculitis centers. Patients were separated into subsequent groups: 2.5 to 3 g vs >3 g cumulative cyclophosphamide induction dose. We investigated if a cyclophosphamide induction dose of 2.5 to 3 g could maintain efficacy while minimizing adverse events in AAV patients with renal involvement.Patients with 2.5 to 3 g vs >3 g cumulative cyclophosphamide (median 3.0 g vs 5.5 g, P < .001) had a comparable time to remission (median 4.0 vs 3.8 months, log-rank P = .87) with 90.6% and 91.5% achieving remission after 12 months. Refractory disease was low in both groups (median 3.6% vs 6.2%, P = .68) and relapse rate did not differ (median 36% vs 42%, log-rank P = .51). Kidney function was comparable at disease onset in both groups (eGFR, mean ± SD 29 ± 20 mL/min/1.73 m2 vs 35 ± 26 mL/min/1.73 m2, P = .34) and improved after 2 years irrespective of the cyclophosphamide dose (ΔeGFR, mean ± SD +8.9 ± 1.4 mL/min/1.73 m2 vs +6.0 ± 1.1 mL/min/1.73 m2, P = .33). The 2.5-3 g group had a lower rate of leukopenia (HR = 2.73 [95% CI, 1.2-6.3], P = .014) and less infectious episodes per patient (median 1.2 vs 0.7, P = .012), especially urinary tract infections (HR = 2.15 [95% CI, 1.1-4.5], P = .032).A cyclophosphamide induction dose of 2.5 to 3 g was able to induce remission and prevent from relapses with fewer cases of leukopenia and less infectious episodes during follow-up. Especially elderly AAV patients who are particularly susceptible to infectious complications could benefit from minimizing dosing regimens with maintained efficacy to control disease activity.

Early Humoral Responses of Hemodialysis Patients after COVID-19 Vaccination with BNT162b2

BACKGROUND AND OBJECTIVES

Patients receiving hemodialysis are at high risk for both severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and severe coronavirus disease 2019. A lifesaving vaccine is available, but sensitivity to vaccines is generally lower in patients on dialysis. Little is yet known about antibody responses after coronavirus disease 2019 (COVID-19) vaccination in this vulnerable group.

DESIGN, SETTING, PARTICIPANTS, AND MEASUREMENTS

In this prospective single-center study, we included 22 patients on dialysis and 46 healthy controls from Heidelberg University Hospital between December 2020 and February 2021. We measured anti-S1 IgG with a threshold index for detection greater than one, neutralizing antibodies with a threshold for viral neutralization of ≥30%, and antibodies against different SARS-CoV2 fragments 17-22 days after the first dose and 18-22 days after the second dose of the mRNA vaccine BNT162b2.

RESULTS

After the first vaccine dose, four of 22 (18%) patients on dialysis compared with 43 of 46 (93%) healthy controls developed positive anti-S1 IgG, with a median anti-S1 IgG index of 0.2 (interquartile range, 0.1-0.7) compared with nine (interquartile range, 4-16), respectively. SARS-CoV2 neutralizing antibodies exceeded the threshold for neutralization in four of 22 (18%) patients on dialysis compared with 43 of 46 (93%) healthy controls, with a median percent inhibition of 11 (interquartile range, 3-24) compared with 65 (interquartile range, 49-75), respectively. After the second dose, 14 of 17 (82%) patients on dialysis developed neutralizing antibodies exceeding the threshold for viral neutralization and antibodies against the receptor binding S1 domain of the spike protein, compared with 46 of 46 (100%) healthy controls, respectively. The median percent inhibition was 51 (interquartile range, 32-86) compared with 98 (interquartile range, 97-98) in healthy controls.

CONCLUSIONS

Patients receiving long-term hemodialysis show a reduced antibody response to the first and second doses of the mRNA vaccine BNT162b2. The majority (82%) develop neutralizing antibodies after the second dose but at lower levels than healthy controls.

Phase I trial of donor-derived modified immune cell infusion in kidney transplantation

BACKGROUNDPreclinical experiments have shown that donor blood cells, modified in vitro by an alkylating agent (modified immune cells [MICs]), induced long-term specific immunosuppression against the allogeneic donor.METHODSIn this phase I trial, patients received either 1.5 × 106 MICs per kg BW on day -2 (n = 3, group A), or 1.5 × 108 MICs per kg BW on day -2 (n = 3, group B) or day -7 (n = 4, group C) before living donor kidney transplantation in addition to post-transplantation immunosuppression. The primary outcome measure was the frequency of adverse events (AEs) until day 30 (study phase) with follow-up out to day 360.RESULTSMIC infusions were extremely well tolerated. During the study phase, 10 treated patients experienced a total of 69 AEs that were unlikely to be related or not related to MIC infusion. No donor-specific human leukocyte antigen Abs or rejection episodes were noted, even though the patients received up to 1.3 × 1010 donor mononuclear cells before transplantation. Group C patients with low immunosuppression during follow-up showed no in vitro reactivity against stimulatory donor blood cells on day 360, whereas reactivity against third-party cells was still preserved. Frequencies of CD19+CD24hiCD38hi transitional B lymphocytes (Bregs) increased from a median of 6% before MIC infusion to 20% on day 180, which was 19- and 68-fold higher, respectively, than in 2 independent cohorts of transplanted controls. The majority of Bregs produced the immunosuppressive cytokine IL-10. MIC-treated patients showed the Immune Tolerance Network operational tolerance signature.CONCLUSIONMIC administration was safe and could be a future tool for the targeted induction of tolerogenic Bregs.TRIAL REGISTRATIONEudraCT number: 2014-002086-30; ClinicalTrials.gov identifier: NCT02560220.FUNDINGFederal Ministry for Economic Affairs and Technology, Berlin, Germany, and TolerogenixX GmbH, Heidelberg, Germany.

P0413THE ICOS+ TREG/ICOS+ TRESP BALANCE HAS A DECISIVE ROLE REGARDING THE PRESERVATION OF THE REMISSION PHASE IN SLE PATIENTS

Background and Aims

An imbalance between CD4+-regulatory T-cells (Tregs) and CD4+-responder T-cells (Tresps) correlates with active disease flares in Systemic Lupus Erythematosus (SLE) patients. Both cell subsets consist of highly proliferative inducible T-cell co-stimulatory molecule expressing (ICOS+-) and less proliferating ICOS--Treg/Tresp cells.

Method

In this study we aimed to examine the role of age-dependent differentiation for maintaining the ICOS+-Treg/ICOS+-Tresp or ICOS--Treg/ICOS--Tresp balance in SLE remission patients compared to active disease patients and to evaluate the influence of proliferation inhibitor or glucocorticoid therapy concerning the maintenance of these equilibria.

Results

In 83 healthy volunteers, the ratio of ICOS+-Tregs/ICOS+-Tresps increased significantly with age, while that of ICOS--Tregs/ICOS--Tresps did not change. In 86 SLE remission patients, medication controlled disease activity was associated with an age-independently increased ratio of both ICOS+-Tregs/ICOS+-Tresps and ICOS--Tregs/ICOS--Tresps. In 13 active disease patients this increased ICOS+-Treg/ICOS+-Tresp ratio could not be maintained, due to an age-dependent earlier terminal differentiation of ICOS+-Tregs than of ICOS+-Tresps. The increased ratio of ICOS--Treg/ICOS--Tresp was maintained in active disease patients, but it decreased with age. This was attributable to an age-independent aberrant differentiation of ICOS--Tresps and a resulting loss of age-dependent differentiation of ICOS--Tregs. Especially the administration of proliferation inhibitors (azathioprine or mycophenolic acid) ensured prolonged differentiation and maintenance of functional ICOS+-Tregs with age. There was a similar but weaker effect of this medication on ICOS+-Tresps, causing a significant decrease of these cells with age. The proliferation capacity was neither affected in ICOS+-Tregs/Tresps nor in ICOS--Tregs/Tresps. As a result, the ratio of ICOS+-Tregs/ICOS+-Tresps increased significantly with age and kept the patients in remission. In contrast, glucocorticoids increased the differentiation of ICOS--Tregs especially in younger individuals, but had an adverse effect on their proliferation capacity.

Conclusion

Our data reveal a crucial role of the ICOS+-Treg/ICOS+-Tresp balance for the maintenance of self-tolerance and avoidance of disease flares in SLE. The used immunosuppressive therapy, especially the administration of proliferation inhibitors, has a decisive effect on the preservation of regular differentiation of all Treg/Tresp subsets with age, and most importantly avoids the terminal differentiation and immune senescence of ICOS+-Tregs.

Vasogenic Brain Edema During Maintenance Hemodialysis : Preliminary Results from Tract-based Spatial Statistics and Voxel-based Morphometry

BACKGROUND

Hemodialysis (HD), especially when first initiated, can cause neurological deterioration. Presumably this is due to transient cerebral edema, which has been observed using diffusion weighted magnetic resonance imaging (MRI) in experimental and human studies; however, this has not been investigated under maintenance hemodialysis (mHD). Moreover, there are no studies to date investigating regional effects of mHD on grey and white matter volumes.

METHODS

In this study eight patients with end stage renal disease (ESRD) were examined immediately before and after mHD sessions with multimodal MRI, including diffusion tensor imaging (DTI) and high-resolution structural imaging. Additionally, eight healthy, age-matched and sex-matched controls were examined for comparison. Data were analyzed using tract-based spatial statistics and voxel-based morphometry.

RESULTS

At baseline, ESRD patients had significantly reduced values of fractional anisotropy (FA) and axial diffusivity as well as bilaterally reduced grey matter volume in the insula, compared with controls. After the mHD session, FA further decreased while axial, radial, and mean diffusivity significantly increased ubiquitously throughout the white matter. Voxel-based morphometry revealed a corresponding significant increase in white matter volume in the central right hemisphere and splenium, as well as in cortical grey matter in the anterior medial frontal and cingulate cortex. None of the patients showed neurological deterioration.

CONCLUSION

In this study ESRD patients showed white matter changes indicative of chronic microstructural damage when compared with healthy controls, as previously reported. In addition, patients showed signs of a transient extracellular cerebral edema, which has not yet been observed in the absence of neurological symptoms.

First-in-human Phase I studies of PRS-080#22, a hepcidin antagonist, in healthy volunteers and patients with chronic kidney disease undergoing hemodialysis

In chronic kidney disease both renal insufficiency and chronic inflammation trigger elevated hepcidin levels, which impairs iron uptake, availability. and erythropoiesis. Here we report the two first-in-human phase 1 trials of PRS-080#22, a novel, rationally engineered Anticalin protein that targets and antagonizes hepcidin. A single intravenous infusion of placebo or PRS-080#22 was administered to 48 healthy volunteers (phase 1a) and 24 patients with end stage chronic kidney disease (CKD) on hemodialysis (phase 1b) at different doses (0.08-16mg/kg for the phase 1a study and 2-8mg/kg for the phase 1b study) in successive dosing cohorts. The primary endpoint for both randomized, double-blind, phase 1 trials was safety and tolerability. Following treatment, all subjects were evaluable, with none experiencing dose limiting toxicities. Most adverse events were mild. One serious adverse event occurred in the phase 1b (CKD patient) study. There were no clinically significant changes in safety laboratory values or vital signs. PRS-080#22 showed dose-proportional pharmacokinetics (PK), with a terminal half-life of approximately three days in healthy volunteers and 10 to 12 days in CKD patients. Serum hepcidin levels were suppressed in a dose dependent manner and remained low for up to 48 hours after dosing. PRS-080#22 dose-dependently mobilized serum iron with increases in both serum iron concentration and transferrin saturation. No consistent changes were observed with regard to ferritin, reticulocytes, hemoglobin, and reticulocyte hemoglobin. Low titer anti-drug-antibodies were detected in five healthy volunteers but in none of the CKD patients. PRS-080#22, a novel Anticalin protein with picomolar affinity for hepcidin, was safe and well-tolerated when administered to healthy volunteers and CKD patients at all doses tested. The drug exhibited linear pharmacokinetics, longer half-life in CKD patients in comparison to healthy volunteers as well as expected pharmacodynamic effects which hold promise for further clinical studies.

Immunosuppressive therapy influences the accelerated age-dependent T-helper cell differentiation in systemic lupus erythematosus remission patients

Background

CD4⁺ T cells are of great importance in the pathogenesis of systemic lupus erythematosus (SLE), as an imbalance between CD4⁺ regulatory T cells (Tregs) and CD4⁺ responder T cells (Tresps) causes flares of active disease in SLE patients. In this study, we aimed to find the role of aberrant Treg/Tresp cell differentiation for maintaining Treg/Tresp cell balance and Treg functionality.

Methods

To determine differences in the differentiation of Tregs/Tresps we calculated the percentages of CD45RA⁺CD31⁺ recent thymic emigrant (RTE) Tregs/Tresps and CD45RA⁺CD31⁻ mature naive (MN) Tregs/Tresps, as well as CD45RA⁻CD31⁺ and CD45RA⁻CD31⁻ memory Tregs/Tresps (CD31⁺ and CD31⁻ memory Tregs/Tresps) within the total Treg/Tresp pool of 78 SLE remission patients compared with 94 healthy controls of different ages. The proliferation capacity of each Treg/Tresp subset was determined by staining the cells with anti-Ki67 monoclonal antibodies. Differences in the autologous or allogeneic Treg function between SLE remission patients and healthy controls were determined using suppression assays.

Results

With age, we found an increased differentiation of RTE Tregs via CD31⁺ memory Tregs and of RTE Tresps via MN Tresps into CD31⁻ memory Tregs/Tresp in healthy volunteers. This opposite differentiation of RTE Tregs and Tresps was associated with an age-dependent increase in the suppressive activity of both naive and memory Tregs. SLE patients showed similar age-dependent Treg cell differentiation. However, in these patients RTE Tresps differentiated increasingly via CD31⁺ memory Tresps, whereby CD31⁻ memory Tresps arose that were much more difficult to inhibit for Tregs than those that emerged through differentiation via MN Tresps. Consequently, the increase in the suppressive activity of Tregs with age could not be maintained in SLE patients. Testing the Tregs of healthy volunteers and SLE patients with autologous and nonautologous Tresps revealed that the significantly decreased Treg function in SLE patients was not exclusively attributed to an age-dependent diminished sensitivity of the Tresps for Treg suppression. The immunosuppressive therapy reduced the accelerated age-dependent Tresp cell proliferation to normal levels, but simultaneously inhibited Treg cell proliferation below normal levels.

Conclusions

Our data reveal that the currently used immunosuppressive therapy has a favorable effect on the differentiation and proliferation of Tresps but has a rather unfavorable effect on the proliferation of Tregs. Newer substances with more specific effects on the immune system would be desirable.

Electronic supplementary material

The online version of this article (10.1186/s13075-018-1778-6) contains supplementary material, which is available to authorized users.

End-stage renal disease, dialysis, kidney transplantation and their impact on CD4+ T-cell differentiation

Premature aging of both CD4⁺ regulatory T (Treg) and CD4⁺ responder-T (Tresp) cells in patients with end-stage renal disease (ESRD) is expected to affect the success of later kidney transplantation. Both T-cell populations are released from the thymus as inducible T-cell co-stimulator-positive (ICOS⁺ ) and ICOS^- recent thymic emigrant (RTE) Treg/Tresp cells, which differ primarily in their proliferative capacities. In this study, we analysed the effect of ESRD and subsequent renal replacement therapies on the differentiation of ICOS⁺ and ICOS^- RTE Treg/Tresp cells into ICOS⁺  CD31^- or ICOS^-  CD31^- memory Treg/Tresp cells and examined whether diverging pathways affected the suppressive activity of ICOS⁺ and ICOS^- Treg cells in co-culture with autologous Tresp cells. Compared with healthy controls, we found an increased differentiation of ICOS⁺ RTE Treg/Tresp cells and ICOS^- RTE Treg cells through CD31⁺ memory Treg/Tresp cells into CD31^- memory Treg/Tresp cells in ESRD and dialysis patients. In contrast, ICOS^- RTE Tresp cells showed an increased differentiation via ICOS^- mature naive (MN) Tresp cells into CD31^- memory Tresp cells. Thereby, the ratio of ICOS⁺ Treg/ICOS⁺ Tresp cells was not changed, whereas that of ICOS^- Treg/ICOS^- Tresp cells was significantly increased. This differentiation preserved the suppressive activity of both Treg populations in ESRD and partly in dialysis patients. After transplantation, the increased differentiation of ICOS⁺ and ICOS^- RTE Tresp cells proceeded, whereas that of ICOS⁺ RTE Treg cells ceased and that of ICOS^- RTE Treg cells switched to an increased differentiation via ICOS^- MN Treg cells. Consequently, the ratios of ICOS⁺ Treg/ICOS⁺ Tresp cells and of ICOS^- Treg/ICOS^- Tresp cells decreased significantly, reducing the suppressive activity of Treg cells markedly. Our data reveal that an increased tolerance-inducing differentiation of ICOS⁺ and ICOS^- Treg cells preserves the functional activity of Treg cells in ESRD patients, but this cannot be maintained during long-term renal replacement therapy.

Cell therapeutic approaches to immunosuppression after clinical kidney transplantation

Refinement of immunosuppressive strategies has led to further improvement of kidney graft survival in recent years. Currently, the main limitations to long-term graft survival are life-threatening side effects of immunosuppression and chronic allograft injury, emphasizing the need for innovative immunosuppressive regimens that resolve this therapeutic dilemma. Several cell therapeutic approaches to immunosuppression and donor-specific unresponsiveness have been tested in early phase I and phase II clinical trials in kidney transplantation. The aim of this overview is to summarize current cell therapeutic approaches to immunosuppression in clinical kidney transplantation with a focus on myeloid suppressor cell therapy by mitomycin C-induced cells (MICs). MICs show great promise as a therapeutic agent to achieve the rapid and durable establishment of donor-unresponsiveness in living-donor kidney transplantation. Cell-based therapeutic approaches may eventually revolutionize immunosuppression in kidney transplantation in the near future.

The role of age-related T-cell differentiation in patients with renal replacement therapy

Dialysis patients have deficiencies regarding the generation of immune responses and show an increased susceptibility for infections. Persisting uremic conditions are made responsible for the increased aging of their immune system. In this study, we analyzed whether age-related differences in the differentiation of both recent-thymic-emigrant-(RTE)-regulatory (Tregs) and RTE-responder T cells (Tresps) into CD31^--memory Tregs/Tresps led to differences in the suppressive activity of naive and memory Tregs on autologous Tresps between healthy volunteers and dialysis patients. We found that regardless of age, the differentiation of RTE-Treg/Tresps into CD31^--memory-Treg/Tresps was significantly increased in dialysis patients. By analyzing the age-related differences in the differentiation of Tregs/Tresps, we saw that in healthy volunteers RTE-Tregs differentiate via CD31⁺-memory Tregs into CD31^--memory Tregs, which may strengthen the suppressive activity of the total Treg pool. In contrast RTE-Tresps of healthy volunteers differentiate via mature naive (MN)-Tresps into CD31^--memory-Tresps, which may weaken the reactivity of the total Tresp pool. Our data revealed that this normal differentiation via MN-Tresps was lost in dialysis patients, suggesting that their Tresps are less sensitive to Treg-mediated immunosuppression. Functional analysis of Tregs on autologous Tresps showed an increasing suppressive activity with age in healthy individuals, who therefore may have a lower risk of developing autoimmune diseases but owing to decreased reactivity of their Tresps are more likely to suffer from infections. In contrast, dialysis patients exhibited a decreasing suppressive activity with age, owing to strengthened Tresp reactivity, which could explain the higher prevalence of chronic inflammatory conditions in these patients.

Switch to an everolimus-facilitated cyclosporine A sparing immunosuppression improves glycemic control in selected kidney transplant recipients

BACKGROUND

Mammalian target of rapamycin inhibitors (mToRi) allow calcineurin inhibitor (CNI) sparing therapy in renal transplant recipients with possible beneficial effects on the long-term allograft function and cardiovascular risk. The influence of mToRi on glucose metabolism is still under discussion.

METHODS

In a retrospective analysis, renal allograft recipients switched from a cyclosporine A (CsA) to an everolimus (EVR)-based immunosuppression in the first year after transplantation were compared with patients on continued CsA treatment. At 6-month intervals, the prevalence of impaired fasting glucose (IFG) and new onset of diabetes after transplantation (NODAT) were assessed.

RESULTS

A total of 146 renal transplant recipients were included. The cumulative prevalence of IFG and NODAT 30-months post-transplantation was significantly lower in patients switched to an immunosuppression with EVR compared to patients on continued CsA treatment (10% vs 22%, P=.049). However, patients switched to EVR showed a higher incidence of acute cellular rejections in the first 12 months (23% vs 11%, P=.048).

CONCLUSION

EVR-based immunosuppression was associated with a similar or even improved glycemic control and improved renal function. However, due to higher rejection rates, patients switched to EVR should be carefully selected as rejection therapy with steroids counteracts the benefit in glycemic control.

Randomized Trial of C5a Receptor Inhibitor Avacopan in ANCA-Associated Vasculitis

Alternative C activation is involved in the pathogenesis of ANCA-associated vasculitis. However, glucocorticoids used as treatment contribute to the morbidity and mortality of vasculitis. We determined whether avacopan (CCX168), an orally administered, selective C5a receptor inhibitor, could replace oral glucocorticoids without compromising efficacy. In this randomized, placebo-controlled trial, adults with newly diagnosed or relapsing vasculitis received placebo plus prednisone starting at 60 mg daily (control group), avacopan (30 mg, twice daily) plus reduced-dose prednisone (20 mg daily), or avacopan (30 mg, twice daily) without prednisone. All patients received cyclophosphamide or rituximab. The primary efficacy measure was the proportion of patients achieving a ≥50% reduction in Birmingham Vasculitis Activity Score by week 12 and no worsening in any body system. We enrolled 67 patients, 23 in the control and 22 in each of the avacopan groups. Clinical response at week 12 was achieved in 14 of 20 (70.0%) control patients, 19 of 22 (86.4%) patients in the avacopan plus reduced-dose prednisone group (difference from control 16.4%; two-sided 90% confidence limit, -4.3% to 37.1%; P=0.002 for noninferiority), and 17 of 21 (81.0%) patients in the avacopan without prednisone group (difference from control 11.0%; two-sided 90% confidence limit, -11.0% to 32.9%; P=0.01 for noninferiority). Adverse events occurred in 21 of 23 (91%) control patients, 19 of 22 (86%) patients in the avacopan plus reduced-dose prednisone group, and 21 of 22 (96%) patients in the avacopan without prednisone group. In conclusion, C5a receptor inhibition with avacopan was effective in replacing high-dose glucocorticoids in treating vasculitis.

Aberrant ICOS+ -T cell differentiation in women with spontaneous preterm labor

PROBLEM

Recent studies revealed appropriate differentiation of recent thymic emigrant (RTE)-regulatory T cells (Tregs) to be crucial for maintaining healthy pregnancy. Currently, the role of responder T cells (Tresps) is not known.

METHOD OF STUDY

Six-color flow cytometric analysis was used to detect differences in the differentiation of highly proliferative inducible co-stimulatory (ICOS)⁺ -RTE-Tregs/Tresps and apoptosis-sensitive ICOS^- -RTE-Tregs/Tresps into mature naïve (MN)-, CD31⁺ -memory and CD31^- -memory Tregs/Tresps in women with spontaneous preterm labor (sPL) compared to healthy pregnancy.

RESULTS

Healthy pregnancy was characterized by an increased differentiation of ICOS⁺ - and ICOS^- -RTE-Tregs, as well as ICOS⁺ -RTE-Tresps via CD31⁺ -memory Tregs/Tresps into CD31^- -memory Tregs/Tresps. Women with sPL showed an early interruption of RTE-Treg/Tresp differentiation. Instead, ICOS⁺ -MN-Tresps and partly ICOS^- -MN-Tregs differentiated into CD31^- -memory Tregs/Tresps, causing a significant reduction of both ICOS⁺ -Tregs and ICOS⁺ -Tresps, but an increase of ICOS^- -Tresps within total CD4⁺ -T-helper cells.

CONCLUSION

Aberrant differentiation of ICOS⁺ -T cells is associated with sPL.

Differentiation of ICOS+ and ICOS- recent thymic emigrant regulatory T cells (RTE T regs) during normal pregnancy, pre-eclampsia and HELLP syndrome

Two different subsets of naturally occurring regulatory T cells (nTregs), defined by their expression of the inducible co-stimulatory (ICOS) molecule, are produced by the human thymus. To examine the differentiation of ICOS(+) and ICOS(-) CD45RA(+) CD31(+) recent thymic emigrant (RTE) T regs during normal pregnancy and in the presence of pre-eclampsia or haemolysis elevated liver enzymes low platelet (HELLP)-syndrome, we used six-colour flow cytometric analysis to determine the changes in the composition of the ICOS(+) and ICOS(-) T reg pools with CD45RA(+) CD31(+) RTE T regs, CD45RA(+) CD31(-) mature naive (MN) T regs, CD45RA(-) CD31(+) and CD45RA(-) CD31(-) memory Tregs. With the beginning of pregnancy until term, we observed a strong differentiation of both ICOS(+) and ICOS(-) CD45RA(+) CD31(+) RTE, but not CD45RA(+) CD31(-) MN T regs, into CD45RA(-) CD31(-) memory T regs. At the end of pregnancy, the onset of spontaneous term labour was associated with a significant breakdown of ICOS(+) CD45RA(-) CD31(-) memory T regs. However, in the presence of pre-eclampsia, there was a significantly increased differentiation of ICOS(+) and ICOS(-) CD45RA(+) CD31(+) RTE T regs into CD45RA(-) CD31(+) memory T regs, wherein the lacking differentiation into CD45RA(-) CD31(-) memory T regs was partially replaced by the increased differentiation of ICOS(+) and ICOS(-) CD45RA(+) CD31(-) MN Tregs into CD45RA(-) CD31(-) memory T regs. In patients with HELLP syndrome, this alternatively increased differentiation of CD45RA(-) CD31(-) MN T regs seemed to be exaggerated, and presumably restored the suppressive activity of magnetically isolated ICOS(+) and ICOS(-) T regs, which were shown to be significantly less suppressive in pre-eclampsia patients, but not in HELLP syndrome patients. Hence, our findings propose that the regular differentiation of both ICOS(+) and ICOS(-) CD45RA(+) CD31(+) RTE T regs ensures a healthy pregnancy course, while their disturbed differentiation is associated with the occurrence of pre-eclampsia and HELLP syndrome.