A multiple redundant genetic switch locks in the transcriptional signature of T regulatory cells

The transcription factor FoxP3 partakes dominantly in the specification and function of FoxP3+CD4+ T regulatory cells (Tregs), but is neither strictly necessary nor sufficient to determine the characteristic Treg signature. Computational network inference and experimental testing assessed the contribution of other transcription factors (TF). Enforced expression of Helios or Xbp1 elicited specific signatures, but Eos, Irf4, Satb1, Lef1 and Gata1 elicited exactly the same outcome, synergizing with FoxP3 to activate most of the Treg signature, including key TFs, and enhancing FoxP3 occupancy at its genomic targets. Conversely, the Treg signature was robust to inactivation of any single cofactor. A redundant genetic switch thus locks-in the Treg phenotype, a model which accounts for several aspects of Treg physiology, differentiation and stability

Cutaneous Pathology of COVID-19 as a Window into Immunologic Mechanisms of Disease.

Many skin manifestations of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection reflect activation of cutaneous and systemic immune responses involving effector pathways of both the innate and adaptive arms of the immune system. This article reviews evidence from the recent clinical and scientific literature that informs the current understanding of the consequences of coronavirus disease 2019 (COVID-19)-induced immune cell activation, as relevant to dermatology. Topics include the clinical consequences of autoantibody production in patients with COVID-19, immunologic evidence for chilblains as a manifestation of SARS-CoV-2 infection, and the relationship between type I interferons and COVID-19 disease severity

Incidence and Characteristics of Delayed Injection Site Reaction to the mRNA-1273 Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) Vaccine (Moderna) in a Cohort of Hospital Employees.

BACKGROUND: mRNA SARS-CoV-2 vaccines are administered to 2 million individuals per day in the United States under US Food and Drug Administration emergency use authorization. METHODS: Observational cohort study of hospital employees who received their first SARS-CoV-2 mRNA vaccination between 14 December 2020 and 8 January 2021, including employees who reported onset of an injection site reaction ≥48 hours after administration of their first or second dose to an employee hotline. RESULTS: Thirteen female employees who received the mRNA-1273 vaccine (Moderna) during the first 3 weeks of the SARS-CoV-2 vaccine rollout at San Francisco General Hospital reported a pruritic rash at the injection site appearing 3 -9 days after receipt of their initial dose. Five had milder or similar reactions with earlier onset after the second dose. One additional female employee reported this delayed reaction only after the second dose. None reported serious adverse events or had symptoms severe enough to seek medical attention. These cases represented 1.1% of the 1275 female employees who received their first mRNA-1273 dose and 2.0% of the 557 who were aged 31 -45 years during this initial vaccine rollout. None of 675 males who initiated mRNA-1273 or 3612 employees of any sex who initiated BNT162b (Pfizer) vaccination during this period reported delayed-onset reactions. CONCLUSIONS: These results suggest that delayed-onset, injection site pruritic rashes after mRNA-1273 SARS-CoV-2 vaccine administration, lasting up to 1 week, occur commonly in females, do not lead to serious sequela, and should not deter receipt of the second vaccine dose

Genetic priming of sensory neurons in mice that overexpress PAR2 enhances allergen responsiveness.

Pruritus is a common symptom of inflammatory skin conditions, including atopic dermatitis (AD). Although primary sensory neurons that transmit pruritic signals are well-cataloged, little is known about the neuronal alterations that occur as a result of skin disruption in AD. To address this question, we examined the molecular and behavioral consequences of challenging Grhl3PAR2/+ mice, which overexpress PAR2 in suprabasal keratinocytes, with serial topical application of the environmental allergen house dust mite (HDM). We monitored behavior and used RNA sequencing, qPCR, and in situ hybridization to evaluate gene expression in trigeminal ganglia (TG), before and after HDM. We found that neither Grhl3PAR2/+ nor wild-type (WT) mice exhibited spontaneous scratching, and pruritogen-induced acute scratching did not differ. In contrast, HDM exacerbated scratching in Grhl3PAR2/+ mice. Despite the absence of scratching in untreated Grhl3PAR2/+ mice, several TG genes in these mice were up-regulated compared to WT. HDM treatment of the Grhl3PAR2/+ mice enhanced up-regulation of this set of genes and induced additional genes, many within the subset of TG neurons that express TRPV1. The same set of genes was up-regulated in HDM-treated Grhl3PAR2/+ mice that did not scratch, but at lesser magnitude. Finally, we recorded comparable transcriptional changes in IL31Tg mice, demonstrating that a common genetic program is induced in two AD models. Taken together, we conclude that transcriptional changes that occur in primary sensory neurons in dermatitis-susceptible animals underlie a genetic priming that not only sensitizes the animal to chronic allergens but also contributes to pruritus in atopic skin disease

Genetic priming of sensory neurons in mice that overexpress PAR2 enhances allergen responsiveness.

Pruritus is a common symptom of inflammatory skin conditions, including atopic dermatitis (AD). Although primary sensory neurons that transmit pruritic signals are well-cataloged, little is known about the neuronal alterations that occur as a result of skin disruption in AD. To address this question, we examined the molecular and behavioral consequences of challenging Grhl3 PAR2/+ mice, which overexpress PAR2 in suprabasal keratinocytes, with serial topical application of the environmental allergen house dust mite (HDM). We monitored behavior and used RNA sequencing, qPCR, and in situ hybridization to evaluate gene expression in trigeminal ganglia (TG), before and after HDM. We found that neither Grhl3 PAR2/+ nor wild-type (WT) mice exhibited spontaneous scratching, and pruritogen-induced acute scratching did not differ. In contrast, HDM exacerbated scratching in Grhl3 PAR2/+ mice. Despite the absence of scratching in untreated Grhl3 PAR2/+ mice, several TG genes in these mice were up-regulated compared to WT. HDM treatment of the Grhl3 PAR2/+ mice enhanced up-regulation of this set of genes and induced additional genes, many within the subset of TG neurons that express TRPV1. The same set of genes was up-regulated in HDM-treated Grhl3 PAR2/+ mice that did not scratch, but at lesser magnitude. Finally, we recorded comparable transcriptional changes in IL31Tg mice, demonstrating that a common genetic program is induced in two AD models. Taken together, we conclude that transcriptional changes that occur in primary sensory neurons in dermatitis-susceptible animals underlie a genetic priming that not only sensitizes the animal to chronic allergens but also contributes to pruritus in atopic skin disease

United States expert panel consensus on uniform nomenclature and diagnosis for neuropathic pruritus

Importance: Neuropathic pruritus is a debilitating condition lacking a uniform approach to nomenclature and diagnosis. Objective: A panel of dermatologist experts in pruritus was convened to develop definitions, diagnostic recommendations, and treatment guidelines for neuropathic pruritus. Evidence review: A roundtable discussion of 10 experts was conducted on November 3, 2021, via the Zoom platform. This study follows the Standards for Reporting Qualitative Research reporting guidelines for qualitative studies. A systematic review of prior literature on the definition, scope, diagnostic, and treatment was performed, looking at sources of treatment from 1991 to 2021. Consensus was defined as >70% agreement for acceptance of a definition or recommendation. A draft of evidence was subjected to revision by all participants and was endorsed by all participants. Findings: The roundtable identified definitions for neuropathic pruritus, which included different forms of the condition based on cause and presentation such as brachioradial pruritus, notalgia paresthetica, and scalp pruritus. Diagnostic and treatment guidelines were also established. Limitations of this process included lack of randomized controlled studies. These recommendations are also based on expert consensus and must be further supported by evidence-based outcomes research. Conclusions: Neuropathic pruritus contains numerous subtypes, causes, diagnostic methods, and treatment modalities. The recommendations developed by this panel are meant to serve as shared nomenclature for future clinical studies

An essential role for miR-15/16 in Treg suppression and restriction of proliferation

The miR-15/16 family targets a large network of genes in T cells to restrict their cell cycle, memory formation, and survival. Upon T cell activation, miR-15/16 are downregulated, allowing rapid expansion of differentiated effector T cells to mediate a sustained response. Here, we used conditional deletion of miR-15/16 in regulatory T cells (Tregs) to identify immune functions of the miR-15/16 family in T cells. miR-15/16 are indispensable to maintain peripheral tolerance by securing efficient suppression by a limited number of Tregs. miR-15/16 deficiency alters expression of critical Treg proteins and results in accumulation of functionally impaired FOXP3loCD25loCD127hi Tregs. Excessive proliferation in the absence of miR-15/16 shifts Treg fate and produces an effector Treg phenotype. These Tregs fail to control immune activation, leading to spontaneous multi-organ inflammation and increased allergic inflammation in a mouse model of asthma. Together, our results demonstrate that miR-15/16 expression in Tregs is essential to maintain immune tolerance