Effects of different amosite preparations on macrophages, lung damages, and autoimmunity

The underlying mechanisms of asbestos-related autoimmunity are poorly understood. As the size, surface reactivity, and free radical activity of asbestos particles are considered crucial regarding the health effects, this study aims to compare the effects of exposure to pristine amosite (pAmo) or milled amosite (mAmo) particles on lung damage, autoimmunity, and macrophage phenotype. Four months after lung exposure to 0.1 mg of amosite, BAL levels of lactate dehydrogenase, protein, free DNA, CCL2, TGF-β1, TIMP-1, and immunoglobulin A of pAmo-exposed C57Bl/6 mice were increased when compared to fluids from control- and mAmo-exposed mice. Effects in pAmo-exposed mice were associated with lung fibrosis and autoimmunity including anti-double-strand DNA autoantibody production. mAmo or pAmo at 20 µg/cm2 induced a pro-inflammatory phenotype characterized by a significant increase in TNFα and IL-6 secretion on human monocyte-derived macrophages (MDMs). mAmo and pAmo exposure induced a decrease in the efferocytosis capacities of MDMs, whereas macrophage abilities to phagocyte fluorescent beads were unchanged when compared to control MDMs. mAmo induced IL-6 secretion and reduced the percentage of MDMs expressing MHCII and CD86 markers involved in antigen and T-lymphocyte stimulation. By contrast, pAmo but not mAmo activated the NLRP3 inflammasome, as evaluated through quantification of caspase-1 activity and IL-1β secretion. Our results demonstrated that long-term exposure to pAmo may induce significant lung damage and autoimmune effects, probably through an alteration of macrophage phenotype, supporting in vivo the higher toxicity of entire amosite (pAmo) with respect to grinded amosite. However, considering their impact on efferocytosis and co-stimulation markers, mAmo effects should not be neglected. KEY MESSAGES: Lung fibrosis and autoimmunity induced by amosite particles depend on their physicochemical characteristics (size and surface) Inhalation exposure of mice to pristine amosite fibers is associated with lung fibrosis and autoimmunity Anti-dsDNA antibody is a marker of autoimmunity in mice exposed to pristine amosite fibers Activation of lung mucosa-associated lymphoid tissue, characterized by IgA production, after exposure to pristine amosite fibers Pristine and milled amosite particle exposure reduced the efferocytosis capacity of human-derived macrophages.

Phenotypic and proteomic analysis of plasma extracellular vesicles highlights them as potential biomarkers of primary Sjögren syndrome

Sjögren syndrome (SjS) is an autoimmune disease characterized by the destruction of the exocrine gland epithelia, causing a dryness of mucosa called sicca symptoms, and whose main life-threatening complication is lymphoma. There is a need for new biomarkers in this disease, notably diagnostic biomarkers for patients with genuine sicca symptoms that do not meet current criteria, and prognostic biomarkers for patients at risk of lymphoma. Plasma extracellular vesicles (EVs) are promising biomarker candidates in several diseases, but their potential has not yet been explored in SjS. In this proof-of-concept study, we characterized EVs from primary SjS patients (pSS, n=12) at the phenotypic and proteomic levels, compared to EVs from healthy donor (HD, n=8) and systemic lupus erythematosus patients (SLE, n=12). Specific plasma EVs subpopulations, derived from neutrophils, endothelial, and epithelial cells, were found increased in pSS. We also identified a pSS proteomic signature in plasma EVs, including neutrophil-, epithelial-, and endothelial-related proteins, such as integrin alpha M (ITGAM), olfactomedin-4 (OLFM4), Ras-related protein RAB10, and CD36. Overall, our results support the relevance of plasma EVs as biomarkers in SjS.

FOSL2 truncating variants in the last exon cause a neurodevelopmental disorder with scalp and enamel defects

PURPOSE

We aimed to investigate the molecular basis of a novel recognizable neurodevelopmental syndrome with scalp and enamel anomalies caused by truncating variants in the last exon of the gene FOSL2, encoding a subunit of the AP-1 complex.

METHODS

Exome sequencing was used to identify genetic variants in all cases, recruited through Matchmaker exchange. Gene expression in blood was analyzed using reverse transcription polymerase chain reaction. In vitro coimmunoprecipitation and proteasome inhibition assays in transfected HEK293 cells were performed to explore protein and AP-1 complex stability.

RESULTS

We identified 11 individuals from 10 families with mostly de novo truncating FOSL2 variants sharing a strikingly similar phenotype characterized by prenatal growth retardation, localized cutis scalp aplasia with or without skull defects, neurodevelopmental delay with autism spectrum disorder, enamel hypoplasia, and congenital cataracts. Mutant FOSL2 messenger RNAs escaped nonsense-mediated messenger RNA decay. Truncated FOSL2 interacts with c-JUN, thus mutated AP-1 complexes could be formed.

CONCLUSION

Truncating variants in the last exon of FOSL2 associate a distinct clinical phenotype by altering the regulatory degradation of the AP-1 complex. These findings reveal a new role for FOSL2 in human pathology.

Bone Marrow Lymphoid Niche Adaptation to Mature B Cell Neoplasms

B-cell non-Hodgkin lymphoma (B-NHL) evolution and treatment are complicated by a high prevalence of relapses primarily due to the ability of malignant B cells to interact with tumor-supportive lymph node (LN) and bone marrow (BM) microenvironments. In particular, progressive alterations of BM stromal cells sustain the survival, proliferation, and drug resistance of tumor B cells during diffuse large B-cell lymphoma (DLBCL), follicular lymphoma (FL), and chronic lymphocytic leukemia (CLL). The current review describes how the crosstalk between BM stromal cells and lymphoma tumor cells triggers the establishment of the tumor supportive niche. DLBCL, FL, and CLL display distinct patterns of BM involvement, but in each case tumor-infiltrating stromal cells, corresponding to cancer-associated fibroblasts, exhibit specific phenotypic and functional features promoting the recruitment, adhesion, and survival of tumor cells. Tumor cell-derived extracellular vesicles have been recently proposed as playing a central role in triggering initial induction of tumor-supportive niches, notably within the BM. Finally, the disruption of the BM stroma reprogramming emerges as a promising therapeutic option in B-cell lymphomas. Targeting the crosstalk between BM stromal cells and malignant B cells, either through the inhibition of stroma-derived B-cell growth factors or through the mobilization of clonal B cells outside their supportive BM niche, should in particular be further evaluated as a way to avoid relapses by abrogating resistance niches.

Neutrophil function and bactericidal activity against Staphylococcus aureus after cardiac surgery with cardiopulmonary bypass

Staphylococcus aureus is the main bacterial pathogen encountered in mediastinitis after cardiac surgical procedures; it remains a devastating complication with a high mortality rate. As neutrophils have a primordial role in the defense against staphylococcus infection and cardiopulmonary bypass (CPB) is known to induce immunosuppression, the aim of this study was to investigate CPB impact on neutrophil functions. Patients without known immunosuppression scheduled for cardiac surgery with CPB were included. Bone marrow and blood samples were harvested before, during, and after surgery. Neutrophil phenotypic maturation and functions (migration, adhesion, neutrophil extracellular trap [NET] release, reactive oxygen species (ROS) production, phagocytosis, and bacteria killing) were investigated. Two types of Staphylococcus aureus strains (one from asymptomatic nasal carriage and another from mediastinitis infected tissues) were used to assess in vitro bacterial direct impact on neutrophils. We found that CPB induced a systemic inflammation with an increase in circulating mature neutrophils after surgery. Bone marrow sample analysis did not reveal any modification of neutrophil maturation during CPB. Neutrophil lifespan was significantly increased and functions such as NET release and ROS production were enhanced after CPB whereas bacteria killing and phagocytosis were not impacted. Results were similar with the two different isolates of Staphylococcus aureus. These data suggest that CPB induces a recruitment of mature neutrophils via a demargination process rather than impacting their maturation in the bone marrow. In addition, neutrophils are fully efficient after CPB and do not contribute to postoperative immunosuppression.

AB0034 EARLY IMMUNIZATION AGAINST TREATMENT IS ASSOCIATED TO POOR CLINICAL RESPONSE AT 6 MONTHS AND LOW NUMBER OF TRANSITIONAL B CELLS AT BASELINE IN RHEUMATOID ARTHRITIS PATIENTS TREATED BY ADALIMUMAB

Background:

Circulating anti-drug antibodies (ADAs) are detectable approximatively in 33% of adalimumab treated rheumatoid arthritis (RA) patients, often within the first 6 months of therapy1-2. Classically, circulating ADAs associate with their specific drugs to form immune complexes, increasing drug clearance, and by this mechanism reducing therapeutic effect3. B cell involvement leading to ADAs production is not yet well established.

Objectives:

To study early ADAs formation according to clinical response to an adalimumab therapy in RA patients and the relationship between ADAs and circulating B cell subsets.

Methods:

28 RA patients and 13 healthy controls were included. Patients all presented inadequately controlled RA under conventional treatment, were naive of biotherapies, and started an adalimumab treatment at baseline (M0). Responder status was determined according to the DAS28CRP score (<or>3.2) at 3 (M3) and 6 months (M6). ADAs plasma concentration >10pg/mL at M3 defined the immunized patient group. Circulating B cell subsets were quantified by flow cytometry at M0 and M3.

Results:

11 (42.3%) patients were immunized at M3. Among them, 4 (36.4%) were responders at M6 and 7 (63.6%) were non-responders. Presence and concentration of ADAs at M3 was associated to non-responder status at M6 (p=0.043; p=0.042). Immunized patients had lower transitional B cells count at M0 compared to non-immunized patients (p=0.031).

Conclusion:

A high but classical proportion of RA patients developed ADAs after only 3 months of adalimumab treatment. This immunization was associated to non-responder status at M6 and to a low blood transitional B cells count at baseline. Our results suggest transitional B cells implication in

RA activity and biotherapy resistance due to immunization. Low concentrations of transitional B cells could be an early biomarker of immunization process against adalimumab.

References:

[1]Bartelds GM et al. JAMA. 2011

[2]Moots RJ et al. PLoS ONE. 2017

[3]Van Schouwenburg PA et al. Ann Rheum Dis. 2013

Table.

Patients characteristics at baseline

CharacteristicsAll RA patients (n=28)M6 responders(n=16)M6 non-responders(n=10)Age (years)60.5 [47-78]65.5 [47-76]54 [47-78]Sex ratio M/F (% of F)0.4 (71,4%)0.5 (68.8%)0.3 (80.0%)Disease duration, (years)5.6 [0.7-43.0]6.8 [1.0-43.0]2.9 [0.7-31.0]Oral steroid use, (%)18 (64,3%)9 (56.2%)8 (80.0%)Oral steroids, dose (mg/day)5.0 [2.0-15]5.0 [4.0-12.5]8.5 [2.5-15.0]Methotrexate use, (%)24 (50.9%)14 (87.5%)8 (80.0%)Methotrexate, dose (mg/week)20 [10-25]20 [10-25]15 [10-20]*Leflunomide use, (%)3 (10.7)1 (6.3%)2 (20.0%)Leflunomide, dose (mg/day)20 [20-20]20 [20-20]20 [20-20]CRP, (mg/dL)5.5 [1.0-57.0]6.6 [1.0-46.8]3.6 [1.0-57.0]DAS28CRP score4.3 [3.3-5.7]4.1 [3.3-5.2]4.5 [3.4-5.7]RF positive, (%)20 (71.4%)12 (75.0%)6 (60.0%)RF, (U/mL)116 [19-640]88 [21-640]181 [19-336]ACPA positive, (%)25 (89.3%)15 (93.8%)8 (80.0%)ACPA, (U/mL)340 [11-340]340 [14-340]340 [11-340]

Values are medians with ranges and frequencies with percentages. *p=0.050.

Figure 1.

Graph 1Immunization against treatment at 3 months and clinical response at 6 months in RA patients (n=26). Presence of ADAs at 3 months is associated to non-responder status at 6 months. Fisher exact test. R, responders at 6 months; NR, non-responders at 6 months; ADA+, immunized patients at 3 months; ADA-, non-immunized patients at 3 months.

Figure 2.

Graph 2Absolute number of transitional B cells at baseline in RA patients (n=28) according to immunized status at 3 months. Immunized patients at 3 months had lower transitional B cells at baseline than non-immunized patients. ADA+, immunized patients at 3 months; ADA-, non-immunized patients at 3 months. Data represent the mean; *p<0.05 by Mann-Whitney U test.

Disclosure of Interests:

None declared

Sustained activation of the Aryl hydrocarbon Receptor transcription factor promotes resistance to BRAF-inhibitors in melanoma

BRAF inhibitors target the BRAF-V600E/K mutated kinase, the driver mutation found in 50% of cutaneous melanoma. They give unprecedented anti-tumor responses but acquisition of resistance ultimately limits their clinical benefit. The master regulators driving the expression of resistance-genes remain poorly understood. Here, we demonstrate that the Aryl hydrocarbon Receptor (AhR) transcription factor is constitutively activated in a subset of melanoma cells, promoting the dedifferentiation of melanoma cells and the expression of BRAFi-resistance genes. Typically, under BRAFi pressure, death of BRAFi-sensitive cells leads to an enrichment of a small subpopulation of AhR-activated and BRAFi-persister cells, responsible for relapse. Also, differentiated and BRAFi-sensitive cells can be redirected towards an AhR-dependent resistant program using AhR agonists. We thus identify Resveratrol, a clinically compatible AhR-antagonist that abrogates deleterious AhR sustained-activation. Combined with BRAFi, Resveratrol reduces the number of BRAFi-resistant cells and delays tumor growth. We thus propose AhR-impairment as a strategy to overcome melanoma resistance.

Evaluation of sFlt-1/PlGF Ratio for Predicting and Improving Clinical Management of Pre-eclampsia: Experience in a Specialized Perinatal Care Center

Background

Management of pregnant women at high risk of pre-eclampsia (PE) requires frequent monitoring, with referral to specialized perinatal care centers. Reliable tests are necessary to improve prediction of PE and related complications and to assess disease severity and progression. An imbalance in two biomarkers, soluble fms-like tyrosine kinase 1 (sFlt-1) and placental growth factor (PlGF), is involved in PE pathogenesis. The sFlt-1 to PlGF ratio is increased in pregnant women before the onset of PE. An elevated ratio is highly predictive of PE, whereas the diagnosis of PE can be ruled out within one week for low ratios. The main objective of this study was to assess whether a low sFlt-1/PlGF ratio, below a cutoff of 38, can predict the absence of PE within one week.

Methods

We performed a prospective, monocentric, observational study to evaluate serum sFlt-1/PlGF ratio (Roche Diagnostics Cobas e411 system) for predicting -PE in a group of 67 high-risk pregnant women (20–37 gestation weeks).

Results

Among the 67 patients included, 53 had a sFlt-1/PlGF ratio lower than 38; none developed subsequent PE leading to a negative predictive value of 100%. Eight patients developed clinical PE. The positive predictive value was 21% at one week and 18% at four weeks, in accordance with previous studies.

Conclusions

The serum sFlt-1/PlGF ratio showed highly predictive performances for ruling out PE. Using these biomarkers in routine management of PE may improve clinical care and avoid inappropriate hospitalization, which has a significant economic impact.

Angiogenic factors sFlt-1 and PlGF in preeclampsia: Prediction of risk and prognosis in a high-risk obstetric population

OBJECTIVES

Despite its simple definition, preeclampsia can have variable and atypical clinical presentations, an unpredictable course, and potential adverse maternal and fetal outcomes. No single test currently predicts risk or prognosis adequately. Scientific advances suggest that an angiogenic imbalance is involved in its pathophysiology. The objective of this study was to investigate the use of sFlt-1, PlGF, and their ratio in predicting preeclampsia.

MATERIALS AND METHODS

In a single-center prospective observational study, we measured the angiogenic markers sFlt-1 and PlGF and calculated the sFlt-1/PlGF ratio in patients at risk of preeclampsia at 20 to 37 weeks of gestation. The main outcomes were the occurrence of preeclampsia and the interval before its onset.

RESULTS

Of the 67 at risk patients included, 8 (12%) developed preeclampsia. For a sFlt-1/PlGF ratio ≥85, the specificity was 93%. The ratio was significantly higher (ratio=104±30) in women with an onset time less than 5 weeks than in those with later preeclampsia (ratio=10±2), P<0.001.

CONCLUSION

In a high-risk population, angiogenic markers appear to be an interesting aid in predicting the onset of preeclampsia with high specificity and in estimating time to onset. However, due to small number of cases of PE, more studies are needed before recommendations to use these markers in daily practice.

Peripheral phenotype and gene expression profiles of combined liver-kidney transplant patients

BACKGROUND AND AIMS

The beneficial effect of one graft on another has been reported in combined transplantation but the associated mechanisms and biological influence of each graft have not yet been established.

METHODS

In multiple analyses, we explored the PBMC phenotype and signature of 45 immune-related messenger RNAs and 754 microRNAs from a total of 235 patients, including combined liver-kidney transplant recipients (CLK), patients with a liver (L-STA) or kidney (K-STA) graft only under classical immunosuppression and patients with tolerated liver (L-TOL) or kidney grafts (K-TOL).

RESULTS

CLK show an intermediary phenotype with a higher percentage of peripheral CD19(+) CD24(+) CD38(Low) memory B cells and Helios(+) Treg cells, two features associated with tolerance profiles, compared to L-STA and K-STA (P < 0.05, P < 0.01). Very few miRNA were significantly differentially expressed in CLK vs. K-STA and even fewer when compared to L-STA (35 and 8, P < 0.05). Finally, CLK are predicted to share common miRNA targets with K-TOL and even more with L-TOL (344 and 411, P = 0.005). Altogether CLK display an intermediary phenotype and gene profile, which is closer to that of liver transplant patients, with possible similarities with the profiles of tolerant patients.

CONCLUSION

These data suggest that CLK patients show the immunological influence of both allografts with liver having a greater influence.