Renal graft function in transplanted patients correlates with CD45RC T cell phenotypic signature

Biomarkers that could predict the evolution of the graft in transplanted patients and that could allow to adapt the care of the patients would be an invaluable tool. Additionally, certain biomarkers can be target of treatments and help to stratify patients. Potential effective biomarkers have been identified but still need to be confirmed. CD45RC, one of the splicing variants of the CD45 molecule, a tyrosine phosphatase that is critical in negatively or positively regulating the TCR and the BCR signaling, is one marker already described. The frequency of CD8+ T cells expressing high levels of CD45RC before transplantation is increased in patients with an increased risk of acute rejection. However, single biomarkers have limited predictive reliability and the correlation of the expression levels of CD45RC with other cell markers was not reported. In this study, we performed a fluorescent-based high dimensional immunophenotyping of T cells on a cohort of 69 kidney transplant patients either with stable graft function or having experienced acute transplant rejection during the first year after transplantation or at the time of rejection. We identified combinations of markers and cell subsets associated with activation/inflammation or Tregs/tolerance (HLA-DR, PD-1, IFNγ, CD28) as significant biomarkers associated to transplant outcome, and showed the importance of cell segregation based on the CD45RC marker to identify the signature of a stable graft function. Our study highlights potential reliable biomarkers in transplantation to predict and/or monitor easily graft-directed immune responses and adapt immunosuppression treatments to mitigate adverse effects.

CD4+ and CD8+ regulatory T cell characterization in the rat using a unique transgenic Foxp3-EGFP model

BACKGROUND

Regulatory T cells (Treg) in diverse species include CD4⁺ and CD8⁺ T cells. In all species, CD8⁺ Treg have been only partially characterized and there is no rat model in which CD4⁺ and CD8⁺ FOXP3⁺ Treg are genetically tagged.

RESULTS

We generated a Foxp3-EGFP rat transgenic line in which FOXP3 gene was expressed and controlled EGFP. CD4⁺ and CD8⁺ T cells were the only cells that expressed EGFP, in similar proportion as observed with anti-FOXP3 antibodies and co-labeled in the same cells. CD4⁺EGFP⁺ Treg were 5-10 times more frequent than CD8⁺EGFP⁺ Treg. The suppressive activity of CD4⁺ and CD8⁺ Treg was largely confined to EGFP⁺ cells. RNAseq analyses showed similarities but also differences among CD4⁺ and CD8⁺ EGFP⁺ cells and provided the first description of the natural FOXP3⁺CD8⁺ Treg transcriptome. In vitro culture of CD4⁺ and CD8⁺ EGFP^- cells with TGFbeta and IL-2 generated induced EGFP⁺ Treg. CD4⁺ and CD8⁺ EGFP⁺ Treg were expanded upon in vivo administration of a low dose of IL-2.

CONCLUSIONS

This new and unique rat line constitutes a useful model to identify and isolate viable CD4⁺ and CD8⁺ FOXP3⁺ Treg. Additionally, it allows to identify molecules expressed in CD8⁺ Treg that may allow to better define their phenotype and function not only in rats but also in other species.

IL-34 deficiency impairs FOXP3+ Treg function in a model of autoimmune colitis and decreases immune tolerance homeostasis

Background

Immune homeostasis requires fully functional Tregs with a stable phenotype to control autoimmunity. Although IL‐34 is a cytokine first described as mainly involved in monocyte cell survival and differentiation, we recently described its expression by CD8⁺ Tregs in a rat model of transplantation tolerance and by activated FOXP3⁺ CD4⁺ and CD8⁺ Tregs in human healthy individuals. However, its role in autoimmunity and potential in human diseases remains to be determined.

Methods

We generated Il34^−/− rats and using both Il34^−/− rats and mice, we investigated their phenotype under inflammatory conditions. Using Il34^−/− rats, we further analyzed the impact of the absence of expression of IL‐34 for CD4⁺ Tregs suppressive function. We investigated the potential of IL‐34 in human disease to prevent xenogeneic GVHD and human skin allograft rejection in immune humanized immunodeficient NSG mice. Finally, taking advantage of a biocollection, we investigated the correlation between presence of IL‐34 in the serum and kidney transplant rejection.

Results

Here we report that the absence of expression of IL‐34 in Il34^−/− rats and mice leads to an unstable immune phenotype, with production of multiple auto‐antibodies, exacerbated under inflammatory conditions with increased susceptibility to DSS‐ and TNBS‐colitis in Il34^−/− animals. Moreover, we revealed the striking inability of Il34^−/− CD4⁺ Tregs to protect Il2rg^−/− rats from a wasting disease induced by transfer of pathogenic cells, in contrast to Il34^+/+ CD4⁺ Tregs. We also showed that IL‐34 treatment delayed EAE in mice as well as GVHD and human skin allograft rejection in immune humanized immunodeficient NSG mice. Finally, we show that presence of IL‐34 in the serum is associated with a longer rejection‐free period in kidney transplanted patients.

Conclusion

Altogether, our data emphasize on the crucial necessity of IL‐34 for immune homeostasis and for CD4⁺ Tregs suppressive function. Our data also shows the therapeutic potential of IL‐34 in human transplantation and auto‐immunity.

Highlights

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Absence of expression of IL‐34 in Il34^−/− rats and mice leads to an unstable immune phenotype, with a production of multiple auto‐antibodies and exacerbated immune pathology under inflammatory conditions.

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Il34^−/− CD4⁺ Tregs are unable to protect Il2rg^−/− rats from colitis induced by transfer of pathogenic cells.

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IL‐34 treatment delayed EAE in mice, as well as acute GVHD and human skin allograft rejection in immune‐humanized immunodeficient NSG mice.

Anti-CD45RC antibody immunotherapy prevents and treats experimental Autoimmune PolyEndocrinopathy Candidiasis Ectodermal Dystrophy syndrome

Targeted monoclonal antibody (mAb) therapies show great promise for the treatment of transplant rejection and autoimmune diseases by inducing more specific immunomodulatory effects than broadly immunosuppressive drugs routinely used. We recently described the therapeutic advantage of targeting CD45RC, expressed at high levels by conventional T cells (Tconv, CD45RChigh), their precursors and terminally differentiated T (TEMRA) cells, but not by regulatory T cells (Tregs, CD45RClow/-). We demonstrated efficacy of anti-CD45RC mAb treatment in transplantation but its potential has not been examined in autoimmune diseases. APECED is a rare genetic syndrome caused by loss-of-function mutations of the key central tolerance mediator, autoimmune regulator (AIRE) leading to abnormal auto-reactive T cell responses and autoantibodies production. Herein, we showed that, in a rat model of APECED syndrome, anti-CD45RC mAb was effective both as prevention and treatment of autoimmune manifestations and inhibited autoantibody development. Anti-CD45RC mAb intervention depleted CD45RChigh T cells, inhibited CD45RChigh B cells, and restored the Treg/Tconv ratio and the altered Tregs transcriptomic profile. In APECED patients, CD45RC was significantly increased in peripheral blood T cells and lesioned organs from APECED patients were infiltrated by CD45RChigh cells. Our observations highlight the potential role for CD45RChigh cells in the pathogenesis of experimental and human APECED syndrome and the potential of anti-CD45RC antibody treatment.

Rapid and Reproducible Differentiation of Hematopoietic and T Cell Progenitors From Pluripotent Stem Cells

Cell therapy using T cells has revolutionized medical care in recent years but limitations are associated with the difficulty of genome editing of the cells, the production of a sufficient number of cells and standardization of the product. Human pluripotent stem cells (hPSCs) can self-renew and differentiate into T cells to provide a standardized homogenous product of defined origin in indefinite quantity, therefore they are of great potential to alleviate limitations of therapeutic T cell production. The differentiation of hPSCs takes place in two steps: first the induction of hematopoietic stem/progenitor cells (HSPCs), then the induction of lymphopoiesis by Notch signaling. However, the differentiation of T cells from hPSCs can be difficult and lack reproducibility. One parameter that needs to be better assessed is the potential of DLL1 vs. DLL4 ligands of the Notch pathway to induce T cells. In addition, culture of hPSCs is labor-intensive and not compatible with GMP production, especially when they are cultured on feeder cells. Thus, the definition of a robust GMP-compatible differentiation protocol from hPSCs cultured in feeder-free conditions would increase the accessibility to off-the-shelf hematopoietic and T cell progenitors derived from hPSCs. In this article, we describe an efficient, rapid and reproducible protocol for the generation of hematopoietic and T cell progenitors in two steps: (1) generation of HSPCs from embryoid bodies (EB) in serum free medium and GMP-compatible feeder-free systems, (2) directed differentiation of hPSC-derived HSPCs into T-cell progenitors in the presence of bone marrow stromal cells expressing Notch-ligands OP9-DLL1 vs. OP9-DLL4.

IL-34 Actions on FOXP3+ Tregs and CD14+ Monocytes Control Human Graft Rejection

Cytokines are major players regulating immune responses toward inflammatory and tolerogenic results. In organ and bone marrow transplantation, new reagents are needed to inhibit tissue destructive mechanisms and eventually induce immune tolerance without overall immunosuppression. IL-34 is a cytokine with no significant homology with any other cytokine but that acts preferentially through CSF-1R, as CSF-1 does, and through PTPζ and CD138. Although IL-34 and CSF-1 share actions, a detailed analysis of their effects on immune cells needs further research. We previously showed that both CD4⁺ and CD8⁺ FOXP3⁺ Tregs suppress effector T cells through the production of IL-34, but not CSF-1, and that this action was mediated through antigen-presenting cells. We showed here by single-cell RNAseq and cytofluorimetry that different subsets of human monocytes expressed different levels of CSF-1R, CD138, and PTPζ and that both CD4⁺ and CD8⁺ FOXP3⁺ Tregs expressed higher levels of CSF-1R than conventional T cells. The effects of IL-34 differed in the survival of these different subpopulations of monocytes and RNAseq analysis showed several genes differentially expressed between IL-34, CSF-1, M0, M1, and also M2 macrophages. Acute graft-vs.-host disease (aGVHD) in immunodeficient NSG mice injected with human PBMCs was decreased when treated with IL-34 in combination with an anti-CD45RC mAb that depleted conventional T cells. When IL-34-differentiated monocytes were used to expand Tregs in vitro, both CD4⁺ and CD8⁺ FOXP3⁺ Tregs were highly enriched and this effect was superior to the one obtained with CSF-1. Human CD8⁺ Tregs expanded in vitro with IL-34-differentiated allogeneic monocytes suppressed human immune responses in an NSG mouse aGVHD model humanized with hPBMCs. Overall, we showed that IL-34 induced the differentiation of human monocytes with a particular transcriptional profile and these cells favored the development of potent suppressor FOXP3⁺ Tregs.

[Difficulties of a longitudinal epidemiological follow-up study in French occupational medicine]

INTRODUCTION

This study was designed to describe the difficulties of epidemiological follow-up of employees by occupational health services.

METHODS

This study was based on two transverse studies conducted by the Pays de la Loire musculoskeletal disorders (MSD) surveillance network. Eighty-three occupational health physicians included 3,710 employees between 2002 and 2005 and had to review them between 2007 and 2009. Thirteen of these physicians changed jobs and 7 changed geographical sector in the same occupational health service.

RESULTS

Another 94 physicians were contacted and 85 agreed to participate in the network. The follow-up rate was 43%: 1,044 employees were reviewed by the physician who saw them on inclusion and 567 employees were reviewed by another physician of the network. The other employees were distributed as follows: 25% were lost to follow-up and their occupational status remained unknown; 23% were still employed with an identified occupational health physician but had not attended a medical visit during the follow-up study; 5% had left the occupational health surveillance system. Only 23 employees refused to participate in the follow-up and 105 employees had a physician who refused to participate.

DISCUSSION

There is therefore a considerable mobility of occupational health physicians, which interfered with follow-up despite their good mobilization and a high percentage of employee are lost to follow-up after having left their jobs. More appropriate systems must be set up to follow populations of employees, such as new collaborations with general practitioners.

Employment and occupational outcomes of workers with musculoskeletal pain in a French region

OBJECTIVES

To study the employment and occupational outcomes of workers who were diagnosed with upper limb musculoskeletal disorders (UL-MSDs) or had complained of upper limb musculoskeletal pain a few years before compared with workers who had no upper limb pain.

METHODS

In 2002-2005, an epidemiological surveillance system was set up. Occupational physicians examined 3710 randomly selected workers. It focused on six UL-MSDs: rotator cuff syndrome, lateral epicondylitis, flexor-extensor peritendinitis of the hands and fingers, de Quervain's disease, carpal tunnel syndrome and ulnar tunnel syndrome. Three groups were constituted: a 'UL-MSD' group (workers with a clinically diagnosed UL-MSD at baseline, 13% of the cohort); a 'PAIN' group (workers with pain in the previous 7 days at baseline and without any clinically diagnosed form, 38%); and a 'HEALTHY' group (workers with no disorder or upper limb pain in the previous 7 days, 49%). They completed a questionnaire between 2007 and 2009.

RESULTS

A total of 2332 responded. Fewer subjects were still in work in the 'UL-MSD' group (79.3%) than in the 'PAIN' (85.9%) and 'HEALTHY' (90.4%) groups, the difference remaining significant after adjusting for gender, age, occupational category, type of company and comorbidities. Of the subjects still in work, 24% had changed their work station in the same company in the 'PAIN' group compared with 19% in the 'HEALTHY' group and 21% in the 'UL-MSD' group.

CONCLUSIONS

This study showed the impact of musculoskeletal pain on employment outcome and the difficulty of keeping workers with musculoskeletal problems at work.

Effects of individual and work-related factors on incidence of shoulder pain in a large working population

OBJECTIVES

The aim of this study was to assess the effects of individual and work-related factors on the incidence of shoulder pain in a large French working population.

METHODS

A total of 3,710 workers of a French region were randomly included in a cross-sectional study between 2002 and 2005. They completed a self-administered questionnaire about musculoskeletal symptoms, individual factors and exposure to work constraints. In 2007, 2,332 responded to a follow-up questionnaire. The Nordic questionnaire was used both times to assess shoulder pain during the preceding 7 days. Associations between incident shoulder pain and individual and work-related factors at baseline were studied by multivariate logistic regression for both genders.

RESULTS

A total of 946 men and 709 women without shoulder pain at baseline were eligible for the analyses. At follow-up, 105 men (11.1%) and 145 women (20.5%) reported shoulder pain. For men, age (OR 3.3, 95% CI, 1.7-6.5 for ≥50 yr), working with arms above the shoulder (1.5; 1.0-2.3) and high perceived physical exertion (1.6; 1.0-2.5) increased the risk of incident shoulder pain. For women, the factors associated with incident shoulder pain were age (2.9; 1.5-5.8 for ≥50 yr), obesity (2.5; 1.4-4.5), temporary employment (2.1; 1.1-3.7), high perceived physical exertion (2.2; 1.4-3.5) and low decision latitude (1.6; 1.0-2.3).

CONCLUSION

Age was the strongest predictor of incident shoulder pain in both genders. BMI and biomechanical and psychosocial factors were also identified as risk factors, whereas no factor related to work organization remained in the final models.

Risk factors for incidence of rotator cuff syndrome in a large working population

OBJECTIVES

The aim of this study was to assess the effects of personal and work-related factors on the incidence of rotator cuff syndrome (RCS) in a large working population.

METHODS

A total of 3710 French workers were included in a cross-sectional study in 2002-2005. All completed a self-administered questionnaire about personal factors and work exposure. Using a standardized physical examination, occupational physicians established a diagnosis of RCS. Between 2007-2010, 1611 workers were re-examined. Associations between RCS and risk factors at baseline were analyzed by logistic regression.

RESULTS

A total of 839 men and 617 women without RCS at baseline were eligible for analysis. RCS was diagnosed in 51 men (6.1%) and 45 women (7.3%). The risk of RCS increased with age for both genders [odds ratio (OR) 4.7 (95% confidence interval [95% CI] 2.2-10.0) for men aged 45-49 years and 5.4 (95% CI 2.3-13.2) for women aged 50-59 years; reference <40 years]. For men, the work-related risk factors were repeated posture with the arms above the shoulder level combined with high perceived physical exertion [OR 3.3 (95% CI 1.3-8.4)] and low coworker support [OR 2.0 (95% CI 1.1-3.9)]. For women, working with colleagues in temporary employment [OR 2.2 (95% CI 1.2-4.2)] and repeated arm abduction (60-90°) [OR 2.6 (95% CI 1.4-5.0)] were associated with RCS.

CONCLUSIONS

Age was the strongest predictor for incident cases of RCS, and arm abduction was the major work-related risk factor for both genders. Lack of social support was a predictor for RCS among men.