Thrombotic thrombocytopenia associated with COVID-19 infection or vaccination: Possible paths to platelet factor 4 autoimmunity.

Michel Goldman and Cédric Hermans discuss thrombotic mechanisms in COVID-19 and rare adverse reactions to SARS-CoV-2 vaccinations.

Patient perspectives regarding gene therapy in haemophilia: Interviews from the PAVING study.

INTRODUCTION: Exploring patient perceptions regarding gene therapies may provide insights about their acceptability to patients. OBJECTIVE: To investigate opinions of people with haemophilia (PWH) regarding gene therapies. Moreover, this study aimed to identify patient-relevant attributes (treatment features) that influence PWH's treatment choices. METHODS: Semi-structured individual interviews were conducted with Belgian PWH, types A and B. A predefined interview guide included information sections and open, attribute ranking and case questions. Qualitative data were organized using NVivo 12 and analysed following framework analysis. Sum totals of scores obtained in the ranking exercise were calculated per attribute. RESULTS: In total, 20 PWH participated in the interviews. Most participants demonstrated a positive attitude towards gene therapy and were very willing (40%; n = 8) or willing (35%; n = 7) to receive this treatment. The following five attributes were identified as most important to PWH in making their choice: annual bleeding rate, factor level, uncertainty of long-term risks, impact on daily life, and probability that prophylaxis can be stopped. While participants were concerned about the uncertainty regarding long-term safety, most participants were less concerned about uncertainty regarding long-term efficacy. CONCLUSIONS: This qualitative study showed that most PWH have a positive attitude towards gene therapy and that besides efficacy, safety and the related uncertainties, also impact on daily life is important to patients. The identified patient-relevant attributes may be used by regulators, health technology assessment bodies and payers in their evaluation of gene therapies for haemophilia. Moreover, they may inform clinical trial design, pay-for-performance schemes and real-world evidence studies.

Patient preferences for gene therapy in haemophilia: Results from the PAVING threshold technique survey.

OBJECTIVES: The aim of the Patient preferences to Assess Value IN Gene therapies (PAVING) study was to investigate trade-offs that adult Belgian people with haemophilia (PWH) A and B are willing to make when choosing between prophylactic factor replacement therapy (PFRT) and gene therapy. METHODS: The threshold technique was used to quantify the minimum acceptable benefit (MAB) of a switch from PFRT to gene therapy in terms of 'Annual bleeding rate' (ABR), 'Chance to stop prophylaxis' (STOP), and 'Quality of life' (QOL). The design was supported by stakeholder involvement and included an educational tool on gene therapy. Threshold intervals were analysed using interval regression models in Stata 16. RESULTS: A total of 117 PWH completed the survey. Mean thresholds were identified for all benefits, but substantial preference heterogeneity was observed; especially for the STOP thresholds, where the distribution of preferences was bimodal. Time spent on the educational tool and residence were found to impact MAB thresholds. The most accepted (88% of PWH) gene therapy profile investigated in this study comprised of zero bleeds per year (vs. six for PFRT), 90% chance to stop prophylaxis, no impact on QoL, and 10 years of follow-up on side effects (vs. 30 for PFRT). CONCLUSIONS: Results from this study proved the value of educating patients on novel treatments. Moreover, preference heterogeneity for novel treatments was confirmed in this study. In gene therapy decision-making, preference heterogeneity and the impact of patient education on acceptance should be considered.

Antibody-based therapies for COVID-19: Can Europe move faster?

Michel Goldman and colleagues call on the European medical and scientific community to coordinate efforts on immunotherapy-based approaches to coronavirus.

The Innovative Medicines Initiative moves translational immunology forward.

The Innovative Medicines Initiative (IMI) was established in 2008 as a public-private partnership between the European Union and the European Federation of Pharmaceutical Industries and Associations with the mission to promote the development of novel therapies through collaborative efforts based on the concept of pre-competitive research. Several consortia supported by IMI are dedicated to immuno-inflammatory disorders, immune-based biopharmaceuticals and vaccines. Herein, we present the key principles underlying IMI, briefly review the status of projects related to translational immunology, and present future topics of interest to immunologists.

Interferon regulatory factor 3 deficiency leads to interleukin-17-mediated liver ischemia-reperfusion injury.

UNLABELLED: Interferon regulatory factor 3 (IRF3) is an important transcription factor in Toll-like receptor 4 (TLR4) signaling, a pathway that is known to play a critical role in liver ischemia-reperfusion injury. In order to decipher the involvement of IRF3 in this setting, we first compared the intensity of hepatic lesions in IRF3-deficient versus wildtype mice. We found increased levels of blood transaminases, enhanced liver necrosis, and more pronounced neutrophil infiltrates in IRF3-deficient mice. Neutrophil depletion by administration of anti-Ly6G monoclonal antibody indicated that neutrophils play a dominant role in the development of severe liver necrosis in IRF3-deficient mice. Quantification of cytokine genes expression revealed increased liver expression of interleukin (IL)-12/IL-23p40, IL-23p19 messenger RNA (mRNA), and IL-17A mRNA in IRF3-deficient versus wildtype (WT) mice, whereas IL-27p28 mRNA expression was diminished in the absence of IRF3. The increased IL-17 production in IRF3-deficient mice was functionally relevant, as IL-17 neutralization prevented the enhanced hepatocellular damages and liver inflammation in these animals. Evidence for enhanced production of IL-23 and decreased accumulation of IL-27 cytokine in M1 type macrophage from IRF3-deficient mice was also observed after treatment with lipopolysaccharide, a setting in which liver gamma-delta T cells and invariant natural killer T cells were found to be involved in IL-17A hyperproduction. CONCLUSION: IRF3-dependent events downstream of TLR4 control the IL-23/IL-17 axis in the liver and this regulatory role of IRF3 is relevant to liver ischemia-reperfusion injury.

Patients' motives for consenting or refusing to participate in a clinical trial in organ transplantation.

BACKGROUND: The goal of this health-psychology study was to investigate the range of motives that make someone consent or refuse participation in a clinical transplant trial. METHODS: The study involved (i) preparatory interviews with five transplant patients who took part in clinical trials and five persons from the general public; (ii) we created a questionnaire with scaled responses; (iii) we selected 468 patients, divided into two groups: patients waiting for a transplant and patients who already had a transplant; (iv) we obtained patient consents, sent out the questionnaire, and recorded responses; (v) data were analysed using descriptive statistics, exploratory factorial analyses, correlations and regressions. RESULTS: Two hundred and ten patients answered the questionnaire. Motives were classified into the following: (i) Motives to consent participating in a clinical trial (pride in participating, hope for better quality of life, sufficient and clear information, discussion with others participating in a trial, altruism); or (ii) Motives to refuse participating (no information on medical teams, lack of explanation, fear of additional expenses, being considered a "guinea pig"). CONCLUSIONS: This study contributes to our understanding of the motivations of patients who accepted or refused participation in a clinical transplantation trial.

Prescription opioids and economic hardship in France.

This paper studies how opioid analgesic sales are empirically related to socioeconomic disparities in France, with a focus on poverty. This analysis is made possible using the OpenHealth database, which provides retail sales data for opioid analgesics available on the French market. We exploit firm-level data for each of the 94 departments in Metropolitan France between 2008 and 2017. We show that increases in the poverty rate are associated with increases in sales: a one percentage point increase in poverty is associated with approximately a 5% increase in mild opioid sales. Our analysis further shows that opioid sales are positively related to the share of middle-aged people and individuals with basic education only, while they are negatively related to population density. The granularity and longitudinal nature of these data allow us to control for a large pool of potential confounding factors. Our results suggest that additional interventions should be more intensively addressed toward the most deprived areas. We conclude that a combination of policies aimed at improving economic prospects and strictly monitoring access to opioid medications would be beneficial for reducing opioid-related harm.

Critical role of the IFN-stimulated gene factor 3 complex in TLR-mediated IL-27p28 gene expression revealing a two-step activation process.

In myeloid dendritic cells, activation of the IL-27p28 gene is selectively induced by ligands of TLR4 or TLR3, both coupled to the Toll/IL-1R-related domain-containing adaptor-inducing IFN/IFN regulatory factor (IRF)3 pathway. In response to both ligands, autocrine type 1 IFN production was required for optimal IL-27p28 expression. Type I IFN signaling was necessary for sustained IRF1 activation and formation of the IRF9-containing IFN-stimulated gene factor 3 complex. Indeed, we demonstrated that IRF1 and IRF9 are sequentially activated and recruited to the IL-27p28 IFN-stimulated regulatory element site. Involvement of IRF1 and IRF9 in the induction of IL-27p28 was confirmed in vitro and upon in vivo exposure to TLR ligands. Thus, in response to TLR4 or TLR3 ligation, the initial induction of the IL-27p28 gene depends on the recruitment of IRF1 and IRF3, whereas transcriptional amplification requires recruitment of the IFN-stimulated gene factor 3 complex. These results highlight the complex molecular interplay between TLRs and type I IFNs for the control of IL-27 synthesis.

Critical role of regulatory T cells in Th17-mediated minor antigen-disparate rejection.

Th17-mediated immune responses have been recently identified as novel pathogenic mechanisms in a variety of conditions; however, their importance in allograft rejection processes is still debated. In this paper, we searched for MHC or minor Ag disparate models of skin graft rejection in which Th17 immune responses might be involved. We found that T cell-derived IL-17 is critical for spontaneous rejection of minor but not major Ag-mismatched skin grafts. IL-17 neutralization was associated with a lack of neutrophil infiltration and neutrophil depletion delayed rejection, suggesting neutrophils as an effector mechanism downstream of Th17 cells. Regulatory T cells (Tregs) appeared to be involved in Th17 reactivity. We found that in vivo Treg depletion prevented IL-17 production by recipient T cells. An adoptive cotransfer of Tregs with naive monospecific antidonor T cells in lymphopenic hosts biased the immune response toward Th17. Finally, we observed that IL-6 was central for balancing Tregs and Th17 cells as demonstrated by the prevention of Th17 differentiation, the enhanced Treg/Th17 ratio, and a net impact of rejection blockade in the absence of IL-6. In conclusion, the ability of Tregs to promote the Th17/neutrophil-mediated pathway of rejection that we have described should be considered as a potential drawback of Treg-based cell therapy.

Regulation of Th2 responses and allergic inflammation through bystander activation of CD8+ T lymphocytes in early life.

Th2-biased immune responses characterizing neonates may influence the later onset of allergic disease. The contribution of regulatory T cell populations in the prevention of Th2-driven pathologies in early life is poorly documented. We investigated the potential of CD8(+) T cells stimulated at birth with alloantigens to modulate the development of allergic airway inflammation. Newborn mice were immunized with semiallogeneic splenocytes or dendritic cells (DCs) and exposed at the adult stage to OVA aeroallergens. DC-immunized animals displayed a strong Th1 and Tc1/Tc2 alloantigen-specific response and were protected against the development of the allergic reaction with reduced airway hyperresponsiveness, mucus production, eosinophilia, allergen-specific IgE and IgG(1), and reduction of lung IL-4, IL-5, IL-10, and IL-13 mRNA levels. By contrast, splenocyte-immunized mice displayed a Th2 and a weak Tc2 alloantigen-specific response and were more sensitive to the development of the allergen-specific inflammation compared with mice unexposed at birth to alloantigens. DC-immunized animals displayed an important increase in the percentage of IFN-gamma-producing CD8(+)CD44(high), CD8(+)CD62L(high), and CD8(+)CD25(+) subsets. Adoptive transfers of CD8(+) T cells from semiallogeneic DC-immunized animals to adult beta(2)m-deficient animals prevented the development of allergic response, in particular IgE, IL-4, and IL-13 mRNA production in an IFN-gamma-dependent manner, whereas transfers of CD8(+) T cells from semiallogeneic splenocyte-immunized mice intensified the lung IL-4 and IL-10 mRNA level and the allergen-specific IgE. These findings demonstrated that neonatal induction of regulatory CD8(+) T cells was able to modulate key parameters of later allergic sensitization in a bystander manner, without recognition of MHC class I molecules.

The rational use of animals in drug development: contribution of the innovative medicines initiative.

Animal models are still widely used to assess the efficacy or safety of new pharmaceutical products. Since their limitations in predicting actions of drugs in humans are becoming more and more apparent, there is an urgent need to revisit the use of animals in pharmaceutical research. Herein, we review how the Innovative Medicines Initiative (IMI), the largest public-private partnership in the life sciences, is reducing, refining and replacing the use of animals in the context of its global mission, namely, to boost research and the development of new medicines across the European Union.

The Safety of Anti-SARS-CoV-2 Vaccines: Vigilance Is Still Required.

The opinion I put forward in this paper is that attention must continue to be paid to clinical observations compatible with a detrimental effect of anti-SARS-CoV-2 in certain diseases of immunological nature. Using the example of the atypical thrombocytopenic thromboses caused by adenoviral-vector-based vaccines, I argue that usual post-marketing pharmacovigilance programs may fail in identifying very rare vaccine-related disorders. Since the robust protective immunity induced by mRNA vaccines is related to their distinct capacity to induce strong stimulation of T follicular helper cells, I suggest that the safety of mRNA vaccines should be further assessed by appropriately designed epidemiological and mechanistic studies focusing on lymphoproliferative and autoimmune diseases in which T follicular helper cells were found to play a key role.

Autoantibodies and SARS-CoV2 infection: The spectrum from association to clinical implication: Report of the 15th Dresden Symposium on Autoantibodies.

The relation between infections and autoimmune diseases has been extensively investigated. Multiple studies suggest a causal relation between these two entities with molecular mimicry, hyperstimulation and dysregulation of the immune system as plausible mechanisms. The recent pandemic with a new virus, i.e., SARS-CoV-2, has resulted in numerous studies addressing the potential of this virus to induce autoimmunity and, eventually, autoimmune disease. In addition, it has also revealed that pre-existing auto-immunity (auto-Abs neutralizing type I IFNs) could cause life-threatening disease. Therefore, the topic of the 15th Dresden Symposium on Autoantibodies was focused on autoimmunity in the SARS-CoV-2 era. This report is a collection and distillation of the topics presented at this meeting.

CD14-independent responses induced by a synthetic lipid A mimetic.

CRX-527 belongs to a new family of synthetic lipid A mimetics, the aminoalkyl glucosaminide 4-phosphates, which are considered as potential vaccine adjuvants or stand-alone immunotherapeutics to harness innate immune defenses. Since natural lipid A from bacterial LPS depends on membrane-bound (mCD14) or soluble CD14 for its TLR4 ligand activity, we investigated the involvement of both forms of CD14 in the responses elicited by CRX-527. First, we found that CRX-527 induces NF-kappaB and interferon regulatory factor-3 (IRF-3) activation in human embryonic kidney cells transfected with TLR4 and MD-2 genes alone, whereas the responses to LPS require either co-transfection of the gene encoding mCD14 or addition of soluble CD14. We then observed that monocyte-derived DC, which are devoid of mCD14 respond to CRX-527 but not to LPS in serum-free medium. Furthermore, we found that, in contrast to LPS, CRX-527 induces the production of cytokines in whole blood of a patient with paroxysmal nocturnal hemoglobinuria, a disease in which mCD14-dependent responses are defective. Finally, we demonstrated that splenocytes from CD14-deficient mice produce cytokines in response to CRX-527 but not to LPS. We conclude that the lipid A mimetic CRX-527 does not require the CD14 co-receptor to elicit TLR4-mediated responses.

PKC-alpha controls MYD88-dependent TLR/IL-1R signaling and cytokine production in mouse and human dendritic cells.

Conventional PKC (cPKC)-alpha regulates TRIF-dependent IFN response factor 3 (IRF3)-mediated gene transcription, but its role in MyD88-dependent TLR signaling remains unknown. Herein, we demonstrate that PKC-alpha is induced by several MyD88-dependent TLR/IL-1R ligands and regulates cytokine expression in human and murine DC. First, inhibition of cPKC activity in human DC by cPKC-specific inhibitors, Gö6976 or HBDDe, downregulated the production of classical inflammatory/immunomodulatory cytokines induced by TLR2, TLR5 or IL-1R but not by TLR3 stimulation. Similarly, dominant negative PKC-alpha repressed Pam(3)CSK(4) induced NF-kappaB- and AP-1-driven promoter activities in TLR2-expressing human embryonic kidney 293 T cells. Dominant negative PKC-alpha inhibited NF-kappaB reporter activity mediated by overexpression of MyD88 but not TRIF. Unexpectedly, BM-derived DC from PKC-alpha(-/-) mice exhibited decreased TNF-alpha and IL-12p40 production induced by both MyD88- and TRIF-dependent ligands. Furthermore, PKC-alpha is coupled to TLR2 signaling proximal to MyD88 since MAPK and IkappaB kinase-alpha/beta phosphorylations and IkappaBalpha degradation were inhibited in PKC-alpha(-/-) BM-derived DC. Finally, co-immunoprecipitation assays revealed that PKC-alpha physically interacts with Pam(3)CSK(4) activated TLR2 in WT but not in MyD88(-/-) DC. Collectively this study identifies a species-specific role of PKC-alpha as a key component that controls MyD88-dependent cytokine gene expression in human and mouse but differentially regulates production of TRIF-dependent cytokines.

Analysis of the peripheral T-cell repertoire in kidney transplant patients.

The long-term stability of renal grafts depends on the absence of chronic rejection. As T cells play a key role in rejection processes, analyzing the T-cell repertoire may be useful for understanding graft function outcomes. We have therefore investigated the power of a new statistical tool, used to analyze the peripheral blood TCR repertoire, for determining immunological differences in a group of 229 stable renal transplant patients undergoing immunosuppression. Despite selecting the patients according to stringent criteria, the patients displayed heterogeneous T-cell repertoire usage, ranging from unbiased to highly selected TCR repertoires; a skewed TCR repertoire correlating with an increase in the CD8(+) /CD4(+) T-cell ratio. T-cell repertoire patterns were compared in patients with clinically opposing outcomes i.e. stable drug-free operationally tolerant recipients and patients with the "suspicious" form of humoral chronic rejection and were found significantly different, from polyclonal to highly selected TCR repertoires, respectively. Moreover, a selected TCR repertoire was found to positively correlate with the Banff score grade. Collectively, these data suggest that TCR repertoire categorization might be included in the calculation of a composite score for the follow-up of patients after kidney transplantation.