Serum Amyloid A Proteins Induce Pathogenic Th17 Cells and Promote Inflammatory Disease.

Lymphoid cells that produce interleukin (IL)-17 cytokines protect barrier tissues from pathogenic microbes but are also prominent effectors of inflammation and autoimmune disease. T helper 17 (Th17) cells, defined by RORγt-dependent production of IL-17A and IL-17F, exert homeostatic functions in the gut upon microbiota-directed differentiation from naive CD4+ T cells. In the non-pathogenic setting, their cytokine production is regulated by serum amyloid A proteins (SAA1 and SAA2) secreted by adjacent intestinal epithelial cells. However, Th17 cell behaviors vary markedly according to their environment. Here, we show that SAAs additionally direct a pathogenic pro-inflammatory Th17 cell differentiation program, acting directly on T cells in collaboration with STAT3-activating cytokines. Using loss- and gain-of-function mouse models, we show that SAA1, SAA2, and SAA3 have distinct systemic and local functions in promoting Th17-mediated inflammatory diseases. These studies suggest that T cell signaling pathways modulated by the SAAs may be attractive targets for anti-inflammatory therapies.

Single-Cell Transcriptional Survey of Ileal-Anal Pouch Immune Cells From Ulcerative Colitis Patients.

BACKGROUND & AIMS: Restorative proctocolectomy with ileal pouch-anal anastomosis is a surgical procedure in patients with ulcerative colitis refractory to medical therapies. Pouchitis, the most common complication, is inflammation of the pouch of unknown etiology. To define how the intestinal immune system is distinctly organized during pouchitis, we analyzed tissues from patients with and without pouchitis and from patients with ulcerative colitis using single-cell RNA sequencing (scRNA-seq). METHODS: We examined pouch lamina propria CD45+ hematopoietic cells from intestinal tissues of ulcerative colitis patients with (n = 15) and without an ileal pouch-anal anastomosis (n = 11). Further in silico meta-analysis was performed to generate transcriptional interaction networks and identify biomarkers for patients with inflamed pouches. RESULTS: In addition to tissue-specific signatures, we identified a population of IL1B/LYZ+ myeloid cells and FOXP3/BATF+ T cells that distinguish inflamed tissues, which we further validated in other scRNA-seq datasets from patients with inflammatory bowel disease (IBD). Cell-type-specific transcriptional markers obtained from scRNA-seq was used to infer representation from bulk RNA sequencing datasets, which further implicated myeloid cells expressing IL1B and S100A8/A9 calprotectin as interacting with stromal cells, and Bacteroidales and Clostridiales bacterial taxa. We found that nonresponsiveness to anti-integrin biologic therapies in patients with ulcerative colitis was associated with the signature of IL1B+/LYZ+ myeloid cells in a subset of patients. CONCLUSIONS: Features of intestinal inflammation during pouchitis and ulcerative colitis are similar, which may have clinical implications for the management of pouchitis. scRNA-seq enables meta-analysis of multiple studies, which may facilitate the identification of biomarkers to personalize therapy for patients with IBD. The processed single cell count tables are provided in Gene Expression Omnibus; GSE162335. Raw sequence data are not public and are protected by controlled-access for patient privacy.

An intestinal organoid-based platform that recreates susceptibility to T-cell-mediated tissue injury.

A goal in precision medicine is to use patient-derived material to predict disease course and intervention outcomes. Here, we use mechanistic observations in a preclinical animal model to design an ex vivo platform that recreates genetic susceptibility to T-cell-mediated damage. Intestinal graft-versus-host disease (GVHD) is a life-threatening complication of allogeneic hematopoietic cell transplantation. We found that intestinal GVHD in mice deficient in Atg16L1, an autophagy gene that is polymorphic in humans, is reversed by inhibiting necroptosis. We further show that cocultured allogeneic T cells kill Atg16L1-mutant intestinal organoids from mice, which was associated with an aberrant epithelial interferon signature. Using this information, we demonstrate that pharmacologically inhibiting necroptosis or interferon signaling protects human organoids derived from individuals harboring a common ATG16L1 variant from allogeneic T-cell attack. Our study provides a roadmap for applying findings in animal models to individualized therapy that targets affected tissues.

Intestinal Macrophages in Resolving Inflammation.

Macrophages not only regulate intestinal homeostasis by recognizing pathogens to control enteric infections but also employ negative feedback mechanisms to prevent chronic inflammation. Hence, macrophages are intriguing targets for immune-mediated therapies, especially when barrier function in the gut is compromised to trigger aberrant inflammatory responses, most notably during inflammatory bowel diseases. Recently, there has been considerable progress in our understanding of human macrophage biology in different tissues, including the intestines. In this review, we discuss some new findings on the properties of distinct populations of intestinal macrophages, how resolution of inflammation and tissue repair by macrophages could be promoted by type 2 cytokines as well as other therapeutic interventions, and highlight some challenges for translating these findings into the future for this exciting area of immunology research.

Malignancies with a tendency to metastasize to the eyelid or ocular structures.

Metastatic tumors to the eye and eyelid are generally seen in patients with disseminated metastases in the setting of advanced disease. Occasionally, they can present as the first sign of occult malignancy. The choroid is the most common site of intraocular metastases secondary to its dense vascular supply. Similar to the eye, metastatic tumors to the eyelid can present with a variety of clinical findings and are most often seen in patients with a known history of cancer. The most common skin malignancy that can spread to ocular structures is cutaneous melanoma, whereas the most common noncutaneous malignancy is breast cancer followed by lung cancer. In pediatric patients, metastatic disease to the eye is rare and can be seen in neuroblastoma and Ewing sarcoma. The overall prognosis of metastatic lesions involving the eye and eyelid is typically poor, with a mean survival of months. Ophthalmologists play an important role in the diagnosis of metastatic disease of the eye and eyelid; therefore, it is imperative for patients to undergo a complete ophthalmic examination and systemic workup if they have new-onset vision changes and a known history of cancer. Early diagnosis and management with systemic and local therapies can maximize quality of life and preserve vision.

Allergic disorders of the eyelid.

Eyelid dermatitis may present with a variety of clinical findings including erythema, pruritus, and edema, and it has a wide differential. Allergic contact dermatitis due to allergen sources in personal care products, cosmetics, and fragrances is a leading cause of eyelid dermatitis and may be challenging to diagnose by clinical examination alone. Expanded patch testing, in addition to careful inspection of the surrounding skin for additional areas of involvement and clinical clues, remains an important tool in differentiating allergic contact dermatitis from other relevant etiologies of eyelid dermatitis including irritant contact dermatitis, atopic dermatitis, seborrheic dermatitis, and rosacea. We present a practical approach to the management of eyelid dermatitis including the use of a topical anti-inflammatory for long-term control of eyelid findings. Further diagnostic workup may be warranted in patients with refractory eyelid dermatitis.

Targeting dysbiosis in psoriasis, atopic dermatitis, and hidradenitis suppurativa: the gut-skin axis and microbiome-directed therapy.

Emerging evidence highlights the gut-skin microbiota as a potential therapeutic target for the management of inflammatory-driven cutaneous diseases as well as the interconnection of the gut-skin microbiota in disease pathogenesis and progression. Although not fully understood, recent research has indicated that commensal microbiota and the interaction of the gut-skin axis play an important role in maintaining skin homeostasis. Dysbiosis and disruption of the skin-gut microbiome may lead to impaired skin barrier function, thus triggering downstream inflammatory responses involved in the development of inflammatory skin disorders, especially in atopic dermatitis, psoriasis, and hidradenitis suppurativa. The skin microbiome may also serve as adjunctive therapeutic modalities for treatment. Herein, we review the latest reports on the interrelationship between microbial dysbiosis and inflammatory cutaneous diseases as well as emerging microbiome-directed therapeutics in atopic dermatitis, psoriasis, and hidradenitis suppurativa.

Histologic Inflammation can Predict Future Clinical Relapse in Ulcerative Colitis Patients in Endoscopic Remission.

Background: In ulcerative colitis (UC), endoscopic improvement, defined as a Mayo Endoscopic Score (MES) of 0 or 1, is a target of treatment. The aim of our study was to evaluate the risk of clinical relapse between patients with an MES of 0 or 1 and determine if histologic activity using the Robarts Histopathologic Index (RHI) was predictive of clinical relapse. Methods: UC patients with an MES score of 0 or 1, no prior colectomy, and at least 1 year of outpatient follow-up after colonoscopy were included. Demographic, clinical characteristics, and clinical relapse were retrospectively collected. Biopsy specimens were read by a gastrointestinal pathologist. Primary outcome was defined as a composite of relapse requiring change in medical therapy, new steroid use, UC-related hospitalization, and/or colectomy. Results: Four hundred and forty-five UC patients were identified. Ninety-five percent of patients with MES 0 were in histologic remission by the RHI whereas only 35% of patients with MES 1 were in histologic remission. Twenty-six percent of patients experienced a clinical relapse; patients with MES 1 or RHI > 3 were significantly more likely to relapse (P < .01) compared to patients with MES 0 or RHI ≤ 3. When patients were stratified into 4 groups (MES 0, RHI ≤ 3; MES 0, RHI > 3; MES 1, RHI ≤ 3; MES 1, RHI > 3) and adjusted for age and sex, RHI > 3 was predictive of relapse (P = .008). Conclusions: UC patients with endoscopic improvement have a high rate of clinical relapse over time. Histologic activity is a predictor of clinical relapse.

Assessment of Photodynamic Therapy Services Performed Among Medicare Beneficiaries from 2018 to 2019.

Objective: Photodynamic therapy (PDT) is a useful treatment modality for premalignant skin lesions. We sought to describe PDT utilization on a national level in the Medicare population post-CPT code revision in 2018 to better understand trends in volume and distribution as well as what factors may influence service performance. Methods: We used the 2018-2019 Medicare Physician and Other Supplier Public Use File to assess PDT services performed during this period. Results: We found that there was an increasing trend of PDT utilization in the Medicare population. While there was less PDT performed without direct involvement of a healthcare professional, an increasing number of PDT services requiring debridement were performed for severe lesions. Although the majority of PDT volume was attributable to dermatologists, non-physician clinicians assumed greater involvement in PDT services. Dermatologists practicing in academic and non-metropolitan settings were less likely to be directly involved with PDT delivery. Conclusion: There is a considerable volume of PDT performed among Medicare beneficiaries, with several utilization trends that may be explained by geographic location and practice setting, among other factors. These findings provide insight to PDT service distribution on a national level and highlight practice patterns that may influence PDT delivery.

The influence of hospitalization and HIV severity on gastrointestinal PCR panel evaluation of HIV-related acute diarrhea in New York City: a retrospective, cross-sectional study.

Introduction: Diarrhea is common in persons living with HIV (PLWH)/AIDS. With the increasing utilization of multiplex gastrointestinal PCR panel (GI panel) testing, we aimed to characterize the roles of CD4 count and hospitalization in GI panel assessments of PLWH with acute diarrhea. Methods: We performed a cross-sectional study of adult PLWH with acute diarrhea who underwent GI panel testing at two urban academic centers. Demographic, HIV disease, GI panel result, and hospitalization data were collected, and patients were cohorted by CD4 count (CD4 < 200, CD4 200-499, CD4 > = 500). The primary outcome was enteric infection as detected by GI panel, and hospitalization. Results: Of 298 PLWH, 119 (39.9%) had a CD4 count below 200, 195 (65.4%) were hospitalized, and 137 (46.0%) had enteric infection. Bacterial infection correlated with higher CD4 count (41.9% (CD4 > = 500) vs 31.2% (CD4 200-499) vs 25.2% (CD4 < 200), p = 0.041). Hospitalization correlated with poorly controlled HIV and fewer enteric infections (34.4% vs 68.0%, p < 0.001). After adjusting for HIV disease severity, a negative GI panel remained independently associated with hospitalization (adjusted odds ratio (aOR) 5.32, 95% confidence interval (CI) 2.72-10.9), even in patients tested within 72 hours of hospitalization. Despite better HIV control, men who have sex with men (MSM) had more frequent infectious diarrhea, including from E. coli, giardiasis, and multiple pathogens. MSM status independently predicted enteric infection (aOR 1.93, 95% CI: 1.02-3.67). Conclusions: GI panel results vary by HIV disease severity and hospitalization in PLWH. Clinicians - especially in the inpatient setting - should carefully consider these factors when interpreting GI panel results. Further characterization of diarrheal etiology in PLWH with a negative GI panel is needed. Plain Language Summary: PCR stool test results are affected by certain factors in HIV-related diarrhea Diarrhea is common in people living with HIV (PLWH) and has a variety of causes, including infections, medications, and HIV itself. Multiplex polymerase chain reaction (PCR) stool testing simultaneously evaluates for a variety of common viral, bacterial, and parasitic infections of the gastrointestinal tract, and is increasingly being used in patients with diarrhea. However, patients with HIV and diarrheal illness may have uncommon infections not typically present in those with normal immune function - and thus not routinely evaluated for in stool testing. It is not known what factors, if any, might affect the results of PCR testing in HIV-related diarrhea.In this study, we examined all PLWH who underwent stool PCR testing for diarrhea over a 4-year period. We separated the patients into groups based on HIV disease severity as measured by CD4 T-cell count, or the count of the immune cells affected by HIV. We examined whether there were differences among groups in infection rates as detected by PCR stool testing. Separately, we studied the role of hospitalization in stool PCR test results.Of 298 PLWH who underwent stool PCR testing for diarrhea, 119 had a CD4 count less than 200 (low CD4 count), 195 were hospitalized at time of testing, and 137 had a positive stool PCR test. Compared to those with a low CD4 count, subjects with less severe HIV disease were more likely to have a bacterial infection on stool PCR testing and less likely to be hospitalized. Hospitalized patients were more likely to have a negative PCR stool test, regardless of CD4 count. Many patients with a low CD4 count had diarrheal etiologies not evaluated by multiplex stool PCR. In PLWH who experience diarrhea, stool PCR testing results vary by CD4 count and hospitalization. Providers should be mindful of these factors when interpreting stool PCR test results.

Comparative Evaluation of Conventional Stool Testing and Multiplex Molecular Panel in Outpatients With Relapse of Inflammatory Bowel Disease.

BACKGROUND: Differentiating between enteric infection and relapse of inflammatory bowel disease (IBD) is a common clinical challenge. Few studies have evaluated the impact of multiplex gastrointestinal polymerase chain reaction (GI PCR) pathogen panels on clinical practice compared to stool culture. Our aim was to compare the impact of PCR stool testing to conventional stool testing in outpatients presenting with relapse of IBD. METHODS: In a retrospective cohort study of outpatients with IBD presenting to NYU Langone Health with flare from September 2015 to April 2019, we compared patients who underwent stool testing with GI PCR to age-, sex-, and IBD-subtype-matched patients who underwent culture and ova and parasite exam (conventional testing). The primary outcome was IBD therapy escalation after testing. Secondary outcomes included rates of posttesting endoscopy, abdominal radiography, antibiotics, and IBD-related emergency department visits, hospitalizations, and abdominal surgeries. RESULTS: We identified 134 patients who underwent GI PCR matched to 134 patients who underwent conventional testing. Pathogens were more frequently identified on GI PCR (26 vs 5%; P < 0.01). We found that GI PCR was associated with less escalation in IBD therapy (16 vs 29%; P < 0.01) and fewer posttest endoscopies (10% vs 18%; P = 0.04), with no differences in IBD outcomes. On multivariate analysis, testing with GI PCR was associated with an odds ratio of 0.26 (95% confidence interval, 0.08-0.84; P = 0.02) for escalation of IBD therapies. CONCLUSIONS: Testing with GI PCR was associated with higher rates of pathogen detection and lower rates of IBD therapy escalation and endoscopy in the outpatient setting. These changes in management were not associated with a difference in IBD outcomes.

IFN-I and IL-22 mediate protective effects of intestinal viral infection.

Products derived from bacterial members of the gut microbiota evoke immune signalling pathways of the host that promote immunity and barrier function in the intestine. How immune reactions to enteric viruses support intestinal homeostasis is unknown. We recently demonstrated that infection by murine norovirus (MNV) reverses intestinal abnormalities following depletion of bacteria, indicating that an intestinal animal virus can provide cues to the host that are typically attributed to the microbiota. Here, we elucidate mechanisms by which MNV evokes protective responses from the host. We identify an important role for the viral protein NS1/2 in establishing local replication and a type I interferon (IFN-I) response in the colon. We further show that IFN-I acts on intestinal epithelial cells to increase the proportion of CCR2-dependent macrophages and interleukin (IL)-22-producing innate lymphoid cells, which in turn promote pSTAT3 signalling in intestinal epithelial cells and protection from intestinal injury. In addition, we demonstrate that MNV provides a striking IL-22-dependent protection against early-life lethal infection by Citrobacter rodentium. These findings demonstrate novel ways in which a viral member of the microbiota fortifies the intestinal barrier during chemical injury and infectious challenges.

Discovery of Selective Cannabinoid CB2 Receptor Agonists by High-Throughput Screening.

The endocannabinoid system (ECS) plays a diverse role in human physiology ranging from the regulation of mood and appetite to immune modulation and the response to pain. Drug development that targets the cannabinoid receptors (CB1 and CB2) has been explored; however, success in the clinic has been limited by the psychoactive side effects associated with modulation of the neuronally expressed CB1 that are enriched in the CNS. CB2, however, are expressed in peripheral tissues, primarily in immune cells, and thus development of CB2-selective drugs holds the potential to modulate pain among other indications without eliciting anxiety and other undesirable side effects associated with CB1 activation. As part of a collaborative effort among industry and academic laboratories, we performed a high-throughput screen designed to discover selective agonists or positive allosteric modulators (PAMs) of CB2. Although no CB2 PAMs were identified, 167 CB2 agonists were discovered here, and further characterization of four select compounds revealed two with high selectivity for CB2 versus CB1. These results broaden drug discovery efforts aimed at the ECS and may lead to the development of novel therapies for immune modulation and pain management with improved side effect profiles.