Exploring the Peer Leadership Network of Rehabilitation Healthcare Professionals Following Leader Development Training.

Purpose: The researcher aimed to identify how rehabilitation professionals engage in their peer leadership network during the first year following leader development training for the purpose of understanding the networking experiences, development of the peer leadership network, and expansion of collective leadership in an organization. Methodology: A sequential exploratory mixed method design including Q-Methodology and focus group interviews identified the experiences of 11 rehabilitation professionals in an urban rehabilitation hospital during the first year following leader development training. Findings: Three themes were identified. These include: (a) an opportunity to connect, (b) a community of leaders, and (c) a healthy peer leadership network emerged from the data analysis. These results indicated that shared experiences and opportunities to connect in a robust peer leadership network can influence the growth of all leaders independent of their current leadership or networking competency. The opportunity to connect for shared discussions in a healthy peer leadership network can accentuate the learning following leader development curriculum as individual leaders develop leadership and as collectives advance organizational outcomes. Practical Implications: Healthcare organizations should facilitate connections in a healthy leadership network to develop individual and collective leadership in an organization.

Efficacy and safety of apremilast in pediatric patients with moderate-to-severe plaque psoriasis: 16-week results from SPROUT, a randomized controlled trial.

BACKGROUND: Approved systemic treatment options are limited for pediatric patients with moderate to severe plaque psoriasis. OBJECTIVE: To assess the efficacy and safety of apremilast over 16 weeks in pediatric patients with plaque psoriasis. METHODS: SPROUT (NCT03701763) was a phase 3, multicenter, randomized, double-blind, placebo-controlled study of apremilast in patients aged 6-17 years with moderate-to-severe psoriasis (Psoriasis Area and Severity Index [PASI] ≥12, body surface area ≥10%, static Physician Global Assessment [sPGA] ≥3) inadequately controlled by/inappropriate for topical therapy. Patients were stratified by age group and randomized (2:1) to apremilast (20 or 30 mg BID based on weight) or placebo for 16 weeks, followed by apremilast extension to 52 weeks. RESULTS: Of 245 patients randomized (apremilast: 163; placebo: 82), 221 (90%) completed the double-blind phase (apremilast: 149; placebo: 72). Significantly more patients achieved sPGA response and ≥75% reduction in PASI with apremilast than placebo, regardless of baseline age, weight, or disease severity. No new safety signals were observed. LIMITATIONS: Sample size of subgroup analyses. CONCLUSIONS: Improvements in global disease activity and skin involvement were significantly greater in pediatric patients treated with apremilast versus placebo. Adverse events were consistent with the known apremilast safety profile.

Therapists' Perception on Quality of Provider Communication While Wearing a Mask: Impact of a Pandemic.

During the COVID-19 pandemic, the Centers for Disease Control and Prevention established infection prevention recommendations, resulting in hospital systems adopting universal mask-wearing. Mask-wearing and its impact on patient-provider communication have been highlighted, yet have not been systematically studied to date. The purpose of this study was to assess the impact of mask-wearing on provider communication during wheelchair education. Allied health professionals (65 physical and occupational therapists and 1 other) completed a 24-item, online self-report survey on the impact of provider mask-wearing on communication with patients and/or their caregivers during wheelchair education. This survey contained questions, graded on 5-point Likert-like scales, regarding the perceived impact of mask-wearing on the quality of communication efficiency and effectiveness, the types and frequency of communication strategies used to enhance communication during breakdowns, knowledge/confidence in implementing communication strategies, and preferences for additional training. Results indicated that mask-wearing impacted communication, yet clinicians made adaptations of various verbal and nonverbal communication strategies to avoid disruptions in providing education. Clinicians identified training preferences for additional support with provider communication. As the pandemic continues, patient-provider communication can be supported through targeted training in communication strategies.

IL-3 receptor signalling suppresses chronic intestinal inflammation by controlling mechanobiology and tissue egress of regulatory T cells.

IL-3 has been reported to be involved in various inflammatory disorders, but its role in inflammatory bowel disease (IBD) has not been addressed so far. Here, we determined IL-3 expression in samples from patients with IBD and studied the impact of Il3 or Il3r deficiency on T cell-dependent experimental colitis. We explored the mechanical, cytoskeletal and migratory properties of Il3r -/- and Il3r +/+ T cells using real-time deformability cytometry, atomic force microscopy, scanning electron microscopy, fluorescence recovery after photobleaching and in vitro and in vivo cell trafficking assays. We observed that, in patients with IBD, the levels of IL-3 in the inflamed mucosa were increased. In vivo, experimental chronic colitis on T cell transfer was exacerbated in the absence of Il-3 or Il-3r signalling. This was attributable to Il-3r signalling-induced changes in kinase phosphorylation and actin cytoskeleton structure, resulting in increased mechanical deformability and enhanced egress of Tregs from the inflamed colon mucosa. Similarly, IL-3 controlled mechanobiology in human Tregs and was associated with increased mucosal Treg abundance in patients with IBD. Collectively, our data reveal that IL-3 signaling exerts an important regulatory role at the interface of biophysical and migratory T cell features in intestinal inflammation and suggest that this might be an interesting target for future intervention.

Differential Effects of Ontamalimab Versus Vedolizumab on Immune Cell Trafficking in Intestinal Inflammation and Inflammatory Bowel Disease.

BACKGROUND AND AIMS: The anti-MAdCAM-1 antibody ontamalimab demonstrated efficacy in a phase II trial in ulcerative colitis and results of early terminated phase III trials are pending, but its precise mechanisms of action are still unclear. Thus, we explored the mechanisms of action of ontamalimab and compared it to the anti-α4ß7 antibody vedolizumab. METHODS: We studied MAdCAM-1 expression with RNA sequencing and immunohistochemistry. The mechanisms of action of ontamalimab were assessed with fluorescence microscopy, dynamic adhesion and rolling assays. We performed in vivo cell trafficking studies in mice and compared ontamalimab and vedolizumab surrogate [-s] antibodies in experimental models of colitis and wound healing. We analysed immune cell infiltration under anti-MAdCAM-1 and anti-α4ß7 treatment by single-cell transcriptomics and studied compensatory trafficking pathways. RESULTS: MAdCAM-1 expression was increased in active inflammatory bowel disease. Binding of ontamalimab to MAdCAM-1 induced the internalization of the complex. Functionally, ontamalimab blocked T cell adhesion similar to vedolizumab, but also inhibited L-selectin-dependent rolling of innate and adaptive immune cells. Despite conserved mechanisms in mice, the impact of ontamalimab-s and vedolizumab-s on experimental colitis and wound healing was similar. Single-cell RNA sequencing demonstrated enrichment of ontamalimab-s-treated lamina propria cells in specific clusters, and in vitro experiments indicated that redundant adhesion pathways are active in these cells. CONCLUSIONS: Ontamalimab has unique and broader mechanisms of action compared to vedolizumab. However, this seems to be compensated for by redundant cell trafficking circuits and leads to similar preclinical efficacy of anti-α4ß7 and anti-MAdCAM-1 treatment. These results will be important for the interpretation of pending phase III data.

Anti-ß7 integrin treatment impedes the recruitment on non-classical monocytes to the gut and delays macrophage-mediated intestinal wound healing.

BACKGROUND: Closing mucosal defects to reach mucosal healing is an important goal of therapy in inflammatory bowel disease (IBD). Among other cells, monocyte-derived macrophages are centrally involved in such intestinal wound healing. We had previously demonstrated that the anti-α4ß7 integrin antibody vedolizumab blocks the recruitment of non-classical monocytes as biased progenitors of wound healing macrophages to the gut and delays wound healing. However, although important for the interpretation of disappointing results in recent phase III trials in IBD, the effects of the anti-ß7 antibody etrolizumab on wound healing are unclear so far. METHODS: We analyzed the expression of etrolizumab targets on human and mouse monocyte subsets by flow cytometry and assessed their function in adhesion and homing assays. We explored wound-associated monocyte recruitment dynamics with multi-photon microscopy and compared the effects of etrolizumab and vedolizumab surrogate (-s) antibodies on experimental wound healing and wound-associated macrophage abundance. Finally, we investigated wound healing macrophage signatures in the large intestinal transcriptome of patients with Crohn's disease treated with etrolizumab. RESULTS: Human and mouse non-classical monocytes expressed more αEß7 integrin than classical monocytes and were a target of etrolizumab-s, which blocked non-classical monocyte adhesion to MAdCAM-1 and E-Cadherin as well as gut homing in vivo. Intestinal wound healing was delayed on treatment with etrolizumab-s along with a reduction of peri-lesional wound healing macrophages. Wound healing macrophage signatures in the colon of patients with Crohn's disease were substantially down-regulated on treatment with etrolizumab, but not with placebo. CONCLUSIONS: Combined blockade of αEß7 and α4ß7 with etrolizumab seems to exceed the effect of anti-α4ß7 treatment on intestinal wound healing, which might help to inform further investigations to understand the recent observations in the etrolizumab phase III trial program.

Expression and function of α4ß7 integrin predict the success of vedolizumab treatment in inflammatory bowel disease.

Inflammatory bowel diseases are medically intractable and require constant therapy in many cases. While a growing number of biologicals and small molecules is available for treatment, a substantial portion of patients experiences primary non-response to these compounds and head-to-head evidence for therapy selection is scarce. Thus, approaches to predict treatment success in individual patients are a huge unmet need. We had previously suggested that the expression and function of α4ß7 integrin on T cells in the peripheral blood correlate to outcomes of therapy with the anti-α4ß7 integrin antibody vedolizumab. Here, we conducted a translational multicenter trial to prospectively evaluate this hypothesis. In a cohort of 89 patients with inflammatory bowel disease undergoing regular therapy with vedolizumab, lower baseline expression of α4ß7 was associated with short-term clinical response. Consistently, low α4ß7 expression in patients achieving remission predicted sustained remission in week 30. Moreover, high dynamic adhesion of CD4+ T cells to MAdCAM-1 and high reduction of adhesion by vedolizumab in vitro at baseline were associated with clinical remission. These data substantiate the potential of α4ß7 integrin function and expression to forecast outcomes of vedolizumab therapy. Further translational efforts are necessary to improve the performance of the assays and to implement the concept in clinical practice.

Point-of-Care Ultrasound-Guided Serratus Anterior Plane Block for Chest Tube Placement in a Spontaneous Pneumothorax.

ABSTRACT: Chest tube placement is a common procedure in the pediatric emergency department. There is general emergency medicine literature as well as pediatric cardiac surgery literature supporting the use of an ultrasound-guided serratus anterior plane block for regional anesthesia with no prior pediatric emergency medicine studies to our knowledge. This case describes a pediatric patient who required chest tube placement twice for a pneumothorax and describes his preference for the nerve block over the more commonly used procedural sedation.

Etrolizumab-s Does Not Induce Residual Trafficking of Regulatory T Cells.

BACKGROUND: Blocking immune cell gut homing via α4ß7 integrin with the monoclonal antibody vedolizumab is an established therapeutic strategy in inflammatory bowel disease. However, despite promising preclinical and phase 2 clinical data, the anti-ß7 antibody etrolizumab yielded disappointing results in a large phase 3 trial program in UC. Mechanistic explanations are still lacking. We have recently shown that vedolizumab is associated with residual homing of regulatory T (Treg) cells in a certain exposure range and aimed to investigate whether a similar mechanism applies for etrolizumab. METHODS: We used flow cytometry, competitive dynamic adhesion, and transmigration assays to assess binding of the etrolizumab surrogate (etrolizumab-s) antibody FIB504 to Treg and effector T cells (Teff) and to explore the impact on cell trafficking. RESULTS: We observed only minimal differences in the binding of etrolizumab-s to Treg and Teff cells. Dynamic adhesion and transmigration of Treg and Teff cells was not substantially differentially affected at relevant concentrations. The ß1+ and PI16+ Treg cells were only resistant to etrolizumab-s at low concentrations. CONCLUSIONS: Etrolizumab does not seem to induce notable residual trafficking of Treg cells. Thus, the Teff overweight in the inflamed gut might persist despite reduced overall T cell recruitment. This might be one piece of the puzzle to explain recent clinical results in phase 3.

The efficacy of etrolizumab in phase 3 was disappointing. Our data suggest that, unlike vedolizumab, etrolizumab does not induce relevant residual trafficking of regulatory T cells. This might be one part of the explanation for recent observations in clinical trials.

Successful use of telemedicine for evaluation of infantile hemangiomas during the early COVID-19 pandemic: A cross-sectional study.

BACKGROUND/OBJECTIVES: The COVID-19 pandemic prompted a rapid expansion in the use of telemedicine. This study aimed to assess the experiences of hemangioma specialists utilizing telemedicine during the COVID-19 pandemic to evaluate and manage infantile hemangiomas (IH), including perceived effectiveness of different modalities and barriers to care delivery. METHODS: Multicenter cross-sectional study asking providers to describe their experiences using telemedicine for initial evaluation of IH from March to September 2020. RESULTS: The study included 281 patients from 15 medical centers internationally. Median time from referral to evaluation was 17 days. Median physician confidence in performing evaluations via telemedicine was 95.0 (IQR 90.0-100.0). Most evaluations were performed via video communication with photographs or audio communication with photographs; when not initially available, photographs were requested in 51.4%. Providers preferred follow-up modalities that included photographs. CONCLUSIONS: Physicians with extensive expertise in managing IH are confident in their abilities to assess and manage IH via telemedicine including initiating treatment in patients without risk factors for beta-blocker therapy. There was a preference for hybrid modalities that included photographs. The data suggest that telemedicine can be effective for managing IH and may decrease wait times and improve specialist reach to underserved areas.

Limited Dose-Dependent Effects of Vedolizumab on Various Leukocyte Subsets.

OBJECTIVES: The anti-α4ß7 integrin antibody vedolizumab (VDZ) is successfully used for the treatment of inflammatory bowel diseases. However, only a subgroup of patients respond to therapy. VDZ is administered at a fixed dose, leading to a wide range of serum concentrations in patients. Previous work from our group showed a dose-dependent preferential binding of VDZ to effector compared with regulatory CD4 + T cells. Therefore, we aimed to determine the dose-dependent binding profile of VDZ to other leukocyte subsets. METHODS: We characterized α4ß7 integrin expression on CD8 + T cells, CD19 + B cells, CD14 + monocytes, natural killer cells, and eosinophils from patients with inflammatory bowel disease and healthy controls. We studied the binding of VDZ to these cells at different concentrations and investigated the functional consequences for dynamic adhesion and transmigration in vitro . RESULTS: The expression of α4ß7 differed between the analyzed leukocyte subsets and was significantly higher on eosinophils from inflammatory bowel disease patients compared with controls. Almost all α4ß7-expressing cells from these subsets were bound by VDZ at a concentration of 10 µg/mL. Dynamic cell adhesion was significantly impaired in all subsets, but there were no dose-dependent differences in the inhibition of adhesion. DISCUSSION: Our data suggest that α4ß7-expressing CD8 + T cells, CD19 + B cells, CD14 + monocytes, natural killer cells, and eosinophils are a target of VDZ. However, there do not seem to be concentration-dependent differences, regarding the effects on these cells in the clinically relevant range. Thus, the reported exposure-efficacy characteristic of VDZ can probably mainly be attributed to CD4 + T-cell subsets.

Global seasonal forecasts of marine heatwaves.

Marine heatwaves (MHWs)-periods of exceptionally warm ocean temperature lasting weeks to years-are now widely recognized for their capacity to disrupt marine ecosystems1-3. The substantial ecological and socioeconomic impacts of these extreme events present significant challenges to marine resource managers4-7, who would benefit from forewarning of MHWs to facilitate proactive decision-making8-11. However, despite extensive research into the physical drivers of MHWs11,12, there has been no comprehensive global assessment of our ability to predict these events. Here we use a large multimodel ensemble of global climate forecasts13,14 to develop and assess MHW forecasts that cover the world's oceans with lead times of up to a year. Using 30 years of retrospective forecasts, we show that the onset, intensity and duration of MHWs are often predictable, with skilful forecasts possible from 1 to 12 months in advance depending on region, season and the state of large-scale climate modes, such as the El Niño/Southern Oscillation. We discuss considerations for setting decision thresholds based on the probability that a MHW will occur, empowering stakeholders to take appropriate actions based on their risk profile. These results highlight the potential for operational MHW forecasts, analogous to forecasts of extreme weather phenomena, to promote climate resilience in global marine ecosystems.

Congenital Syphilis and the Prozone Phenomenon: Case Report.

Congenital syphilis represents an important public health challenge in the United States, and its prevalence has been increasing for the past 10 years because of many factors. The diagnosis can be difficult given its various and nonspecific clinical manifestations in newborns, and the possibility of false negative results during prenatal care. The prozone phenomenon, caused by an excess of antibody, which interferes with the regular screening tests, is a cause of false negative tests. This could delay the diagnosis and increase morbidity and mortality in the newborn. We present a case of congenital syphilis in a 3-month-old infant whose mother had prenatal care and negative tests for syphilis, which contributed to the late diagnosis. In the face of clinical findings suggestive of congenital syphilis and negative maternal syphilis tests healthcare providers should consider the possibility of maternal false negative test caused by the prozone phenomenon.

Residual homing of α4ß7-expressing ß1+PI16+ regulatory T cells with potent suppressive activity correlates with exposure-efficacy of vedolizumab.

OBJECTIVE: The anti-α4ß7 integrin antibody vedolizumab is administered at a fixed dose for the treatment of IBDs. This leads to a wide range of serum concentrations in patients and previous studies had suggested that highest exposure levels are associated with suboptimal clinical response. We aimed to determine the mechanisms underlying these non-linear exposure-efficacy characteristics of vedolizumab. DESIGN: We characterised over 500 samples from more than 300 subjects. We studied the binding of vedolizumab to T cells and investigated the functional consequences for dynamic adhesion, transmigration, gut homing and free binding sites in vivo. Employing single-cell RNA sequencing, we characterised α4ß7 integrin-expressing T cell populations 'resistant' to vedolizumab and validated our findings in vitro and in samples from vedolizumab-treated patients with IBD. We also correlated our findings with a post-hoc analysis of the Gemini II and III studies. RESULTS: Regulatory T (TReg) cells exhibited a right-shifted vedolizumab binding profile compared with effector T (TEff) cells. Consistently, in a certain concentration range, the residual adhesion, transmigration, homing of and availability of functional α4ß7 on TReg cells in vivo was higher than that of/on TEff cells. We identified a vedolizumab-'resistant' α4ß7-expressing ß1+PI16+ TReg cell subset with pronounced regulatory properties as the substrate for this effect. Our observations correlated with exposure-efficacy data from Gemini II and III trials. CONCLUSION: Completely blocking TEff cell trafficking with vedolizumab, while simultaneously permitting residual homing of powerful TReg cells in an optimal 'therapeutic window' based on target exposure levels might be a strategy to optimise treatment outcomes in patients with IBD.

Higher rates of skin clearance and efficacy in challenging body areas are associated with better health-related quality of life following ixekizumab maintenance treatment in pediatric patients with plaque psoriasis.

BACKGROUND/OBJECTIVES: Information is limited on the relationship between skin clearance, resolution of challenging body areas, and improvement of patient-reported outcomes (PROs) in pediatric psoriasis. Ixekizumab, a high-affinity monoclonal antibody that selectively targets interleukin-17A, is approved for the treatment of moderate-to-severe psoriasis in patients aged 6 to <18 years. This study examines improvement in psoriasis clearance in challenging body areas in pediatric patients relative to health-related quality of life. METHODS: Data from the IXORA-PEDS trial (NCT03073200) were analyzed, and changes from baseline were measured for overall Psoriasis Area and Severity Index (PASI), static Physicians' Global Assessment of psoriasis (sPGA), Psoriasis Scalp Severity Index (PSSI), Palmoplantar Psoriasis Area and Severity Index (PPASI), and Nail Psoriasis Severity Index. Rates of Dermatology Life Quality Index (DLQI), or Children's DLQI (CDLQI), scores of 0 or 1 were evaluated using the Cochran-Armitage trend test. RESULTS: Higher rates of DLQI/CDLQI (0,1) scores were significantly associated with greater PASI and PSSI responses at both Week 12 and Week 48 (p < .0001). A significant association was also observed between DLQI/CDLQI (0,1) and sPGA scores (p < .0001). Significantly higher rates of DLQI/CDLQI (0,1) scores were achieved in patients with greater levels of palmoplantar clearance as measured by PPASI at Week 12 (p = .0139), but significance was not sustained at Week 48 (p = .0896). CONCLUSIONS: Greater skin clearance and scalp resolution are associated with better PROs over a short-term (12-week) and long-term (48-week) period. This demonstrates that greater improvement of skin clearance and scalp resolution may benefit quality of life in pediatric patients with psoriasis.

Recruitment strategies and lessons learned from a large genetic study of African Americans.

Genetic studies must enroll large numbers of participants to obtain adequate statistical power. Data are needed on how researchers can best use limited financial and practical resources to achieve these targets, especially in under-represented populations. This paper provides a retrospective analysis of the recruitment strategies for a large glaucoma genetics study in African Americans. The Primary Open-Angle African American Glaucoma Genetics study enrolled 10,192 African American subjects from the Philadelphia region. Major recruitment approaches included clinic enrollment from University of Pennsylvania (UPenn) sites, clinic enrollment from external sites, sampling of Penn Medicine Biobank (PMBB), and community outreach. We calculated the enrollment yield, cost per subject, and seasonal trends of these approaches. The majority (65%) of subject were enrolled from UPenn sites with an average cost of $133/subject. Over time, monthly case enrollment declined as the pool of eligible subjects was depleted. Expanding to external sites boosted case numbers ($129/subject) and the biobank provided additional controls at low cost ($5/subject), in large part due to the generosity of PMBB providing samples free of cost. Community outreach was costly with low return on enrollment ($978/subject for 220 subjects). Summer months (Jun-Aug) produced the highest recruitment yields (p<0.001). Genetic studies will benefit from a multi-pronged and culturally sensitive recruitment approach. In our experience, the biobank was most cost-effective for control enrollment, while recruitment from clinics (including expansion to new sites) was necessary to recruit fully phenotyped cases.

Acquired Acrodermatitis Enteropathica in an Infant.

Acrodermatitis enteropathica (AE) is an acquired or inborn (congenital) disorder of zinc metabolism that leads to zinc deficiency. The congenital form typically presents in infants during the first few months of life when they are weaned from breast milk, presenting even earlier in those who are formula fed. Acquired deficiency may be seen at any age. The characteristic clinical features of AE include erythematous, dry, scaly papules and plaques that may evolve into crusted, erosive, pustular lesions. These lesions typically are distributed in an acral and periorificial pattern and are associated with alopecia and diarrhea. Evidence-based recommendations are sparse but generally indicate 3 mg/kg/d of oral zinc supplementation for both congenital and acquired AE. Appropriate dosing helps to avoid acute zinc toxicity involving nausea and vomiting. We report a case of a 3-month-old female infant with acquired AE who was successfully treated with zinc supplementation over the course of 3 weeks.

α4ß7 integrin-dependent adhesion of T cells to MAdCAM-1 is blocked by vedolizumab in patients with chronic refractory pouchitis.

BACKGROUND: The anti-α4ß7 integrin antibody vedolizumab is an established therapeutic option for the treatment of inflammatory bowel disease (IBD). It has also been successfully used in patients with chronic antibiotic-refractory pouchitis following proctocolectomey with ileal pouch-anal anastomosis. However, the expression and function of gut-homing markers as well as strategies to predict the response to vedolizumab in pouchitis are understudied so far. METHODS: We used flow cytometry and dynamic adhesion assays to study the expression and function of gut-homing integrins on T cells from patients with pouchitis and controls as well as longitudinally during therapy of pouchitis with vedolizumab. Moreover, we describe clinical effects of vedolizumab in a cohort of patients with pouchitis. RESULTS: T cells from patients with pouchitis express a specific profile of gut-homing integrins. Integrin α4ß7 on T cells from patients with pouchitis mediates adhesion to mucosal addressin cell adhesion molecule (MAdCAM)-1, which can be blocked by vedolizumab in vitro. Vedolizumab efficiently treats pouchitis in a portion of patients and response correlates with dynamic adhesion profiles to MAdCAM-1. CONCLUSION: Our data suggest that T cell trafficking seems to be important for the pathogenesis of pouchitis and support the therapeutic use of vedolizumab. Integrin function might serve as a biomarker to predict response to vedolizumab.

Circulating Adaptive Immune Cells Expressing the Gut Homing Marker α4ß7 Integrin Are Decreased in COVID-19.

Background: Infection with the novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) causes a wide range of symptoms including gastrointestinal manifestations, and intestinal epithelial cells are a target of the virus. However, it is unknown how the intestinal immune system contributes to systemic immune responses in coronavirus disease 2019 (COVID-19). Methods: We characterized peripheral blood lymphocytes from patients with active COVID-19 and convalescent patients as well as healthy controls by flow cytometry. Results: The frequency and absolute number of circulating memory T and B cells expressing the gut homing integrin α4ß7 integrin was reduced during COVID-19, whether gastrointestinal symptoms were present or not. While total IgA-expressing B cells were increased, gut-imprinted B cells with IgA expression were stable. Conclusion: COVID-19 is associated with a decrease in circulating adaptive immune cells expressing the key gut homing marker α4ß7 suggesting that these cells are preferentially recruited to extra-intestinal tissues independently of α4ß7 or that the systemic immune response against SARS-CoV-2 is at least numerically dominated by extraintestinal, particularly pulmonary, immune cell priming.

Targeting Immune Cell Trafficking - Insights From Research Models and Implications for Future IBD Therapy.

Inflammatory bowel diseases (IBDs), including Crohn's disease (CD) and ulcerative colitis (UC) are multifactorial diseases with still unknown aetiology and an increasing prevalence and incidence worldwide. Despite plentiful therapeutic options for IBDs, the lack or loss of response in certain patients demands the development of further treatments to tackle this unmet medical need. In recent years, the success of the anti-α4ß7 antibody vedolizumab highlighted the potential of targeting the homing of immune cells, which is now an important pillar of IBD therapy. Due to its complexity, leukocyte trafficking and the involved molecules offer a largely untapped resource for a plethora of potential therapeutic interventions. In this review, we aim to summarise current and future directions of specifically interfering with immune cell trafficking. We will comment on concepts of homing, retention and recirculation and particularly focus on the role of tissue-derived chemokines. Moreover, we will give an overview of the mode of action of drugs currently in use or still in the pipeline, highlighting their mechanisms and potential to reduce disease burden.