Α4β7 Integrin Research Articles

Expression of IL-7RαlowCX3CR1+ CD8+ T Cells and α4β7 Integrin Tagged T Cells Related to Mucosal Immunity in Children with Inflammatory Bowel Disease.

The study aimed to investigate the recruiting of T lymphocytes including IL-7Rαlow CX3CR1+ effector memory (EM) CD8+ T cells and α4β7 integrin tagged T cells to inflamed intestinal mucosa. Whole blood and mucosal tissues of intestine were collected from 40 children with or without inflammatory bowel disease (IBD). T cell surface staining and immunohistochemistry were done with several antibodies in peripheral blood mononuclear cells (PBMCs) and intestinal mucosa, respectively. Serum levels of cytokines were measured by ELISA. The frequency of IL-7RαlowCX3CR1+ EM CD8+ T cells in the PBMC was significantly higher in the ulcerative colitis group than in the control group (57.9±17.80% vs. 33.9±15.70%, p=0.021). The frequency of integrin α4β7+ CD4+ T cells in the PBMC was significantly lower in the ulcerative colitis group than in the control group (53.2±27.6% vs. 63.9±13.2%, p=0.022). Serum concentration of TNF-α was higher in the Crohn's disease group than in the control group (26.13±5.01 pg/mL vs. 19.65±6.07 pg/mL, p=0.008). Of the three groups, the ulcerative colitis group had the highest frequency of integrin α4β7+ T cells based on immunohistochemistry analyses for intestinal tissues, followed by the Crohn's disease group and the control group (4.63±1.29 cells vs. 2.0±0.57 cells vs. 0.84±0.52 cells, p<0.001). Trafficking immune cells with effector memory CD8+ T cells clarified by IL-7RαlowCX3CR1+ and integrin α4β7+ CD4+ T cells might be highly associated with the pathogenesis of ulcerative colitis.

Effect of Integrin Blockade on Experimental Spondyloarthritis.

Spondyloarthritis (SpA) describes a group of diseases characterized by chronic inflammation in the spine and peripheral joints. While pathogenesis is still unclear, proinflammatory gut-derived immune cells have been identified in the joints of SpA patients. We previously identified an enriched population of integrin-expressing cells in the joints of SpA patients. Entry of gut-derived cells into joints may be mediated by these integrins. In the current study, we used the SKG murine model of SpA to study the impact of integrin blockade. Mice were injected with antibodies against the integrin α4β7 or the β7 monomer twice a week. Treatment with antibodies against α4β7 reduced disease severity in curdlan-injected SKG mice, with disease scores being comparable between treatment initiation times. Targeting the β7 monomer led to reduced arthritis severity compared to targeting the α4β7 dimer. Treatment with antibodies against α4β7 or β7 decreased expression of these integrins in CD4+ T cells, with the frequency of αE+β7+ T cells in the spleen and lymph nodes correlating with disease severity. In summary, we showed that integrin blockade showed potential for ameliorating disease in a murine model of SpA, lending support for further studies testing integrin blockade in SpA.

B-266 Therapeutic Drug Monitoring of Natalizumab and Anti-Natalizumab Antibodies

Abstract Background Natalizumab (NTZ) is a monoclonal antibody directed against the α4-integrin subunit of α4β1 and α4β7 integrins. NTZ is used to treat relapsing and remitting forms of multiple sclerosis. Although a majority of patients on standard dosing (intravenous 300 mg, every 4 weeks) reach therapeutic drug concentrations, about 10% of patients will eventually fail NTZ therapy due to the development of anti-NTZ antibodies. NTZ and anti-NTZ antibody concentrations in serum are used together to provide patient-specific pharmacokinetic and immunogenic assessment to aid in patient management. Methods Serum measurements of NTZ and anti-NTZ antibody levels are performed by lab developed electro-chemiluminescent immunoassays where assay design and principle are equivalent to biologic therapeutic drug monitoring described in our previous publication. The natalizumab drug assay is an immunoassay validated to measure free drug (pharmacodynamically active, ADA-unbound) in serum. The anti-natalizumab antibody assay utilizes a solution phase bridging method designed to measure total binding antibodies (including IgM &amp; IgG subtypes). All anti-natalizumab antibody positive samples are confirmed for drug-specificity by an additional signal suppression step. The anti-natalizumab antibody assay is quantitative and drug-tolerant, meaning that circulating drug in patient serum does not interfere with anti-NTZ detection and quantitation. Results Here, we report concomitant measurement of NTZ and anti-NTZ antibody in 160 patient serum samples. Positive anti-NTZ levels from 24 to 235 ng/mL were found in 7.5% (12/160) patients. Anti-NTZ-free samples (148/160) had NTZ drug levels ranging from undetectable (&amp;lt;1.0) to 85 ug/mL. The mean and median drug level in 90 samples (results &amp;gt;1.0) was 10.8 and 2.7, respectively. 61/90 samples had therapeutic drug concentrations (at least 2.0 ug/mL). In the presence of anti-NTZ, 67% (8/12) had undetectable drug level and (4/12) had mean and median drug levels of 1.2 and 1.3, respectively, which is 9- or 2-fold lower than the mean and median drug levels of the anti-NTZ Ab -free group. Conclusions Low serum NTZ and high anti-NTZ are associated with loss of clinical efficacy, while elevated NTZ may increase progressive multifocal leukoencephalopathy risk. Assays to measure biologic drugs and their anti-drug antibodies in patient serum may be useful tools in dose optimization and patient management.

Association Between Vedolizumab Treatment and Arthritis/Arthralgia in Patients with Inflammatory Bowel Disease: A Systematic Review and Meta-analysis.

Vedolizumab is a humanized gut selective drug that targets α4β7 integrin and has been used successfully in the treatment of inflammatory bowel disease (IBD). Pivotal studies have already demonstrated the drug's safety, but some real-life cohorts have shown an increase in arthralgia and arthritis in patients using vedolizumab. These findings raised the question of whether these joint symptoms are extraintestinal manifestations of IBD (since the drug acts only in the gut) or if they are associated with the use of vedolizumab. This systematic review and meta-analysis aimed to assess the incidence of arthralgia/arthritis in patients receiving vedolizumab and to investigate whether these events are indeed drug related. Pubmed, Cochrane, and Scopus were searched for randomized clinical trials reporting the incidence of joint manifestations in patients with Crohn's disease (CD) or ulcerative colitis (UC) who were treated with vedolizumab. The considered outcomes were arthritis and arthralgia. We used RevMan to calculate the pooled incidence of the reported outcomes and their corresponding 95% confidence intervals (95% CI). The search strategy yielded 4,206 articles. After removal of duplicates and screening of results, 6 randomized studies met the inclusion criteria. A total of 3,134 patients with moderately to severe IBD were included. Of those, 2,119 were randomized to receive vedolizumab and 1,015 to placebo. In the intervention group, 210 patients developed arthritis or arthralgia of any kind while 84 patients developed those symptoms in the placebo group (RR=1.09; 95%CI: 0.86-1.38; p=0.49, I2=0%), showing no significant association. Results also showed no significant association between exposure and the studied outcome after comparing CD (RR=1.02; 95%CI: 0.76-1.37, p=0.89, I2=0%) and UC (RR=1.24; 95%CI: 0.81-1.89, p=0.32, I2=43%) separately. The meta-analysis showed no association of these symptoms to the treatment with vedolizumab. Therefore, the new onset of worsening arthritis and arthralgia may be associated with the course of the disease itself, with the body's response to the drugs or with the exclusion of corticosteroids or anti-TNF from concomitant treatment with vedolizumab. Further studies with larger sample sizes are required, especially randomized clinical trials comparing anti-TNF, corticosteroid and immunomodulators to evaluate the incidence of joint manifestations in patients with IBD and even other rheumatological manifestations that may be associated as well.

Expression of integrin α4β1 and α4β7 on B cells correlates with autoimmune responses in Graves’ disease

BackgroundIntegrins are upregulated on endothelial cells and T-lymphocytes in autoimmune thyroid disease (AITD), potentially contributing to immune response localization. The role of integrins on B-cells in AITD remains unclear. MethodsPeripheral blood samples were collected from healthy controls (n = 56), patients with Graves’ disease (GD) (n = 37) and Hashimoto’s thyroiditis (HT) (n = 52). Ultrasound-guided fine-needle aspiration (FNA) of the thyroid was performed in patients with non-autoimmune thyroid disease (nAITD) (n = 19), GD (n = 11), and HT (n = 40). Integrins α4β7, α4β1, and αEβ7 in B cells were measured by flow cytometry. Serum zonulin levels were quantified via ELISA. Associations of integrins on B cells with thyroid hormones, thyroid autoantibodies, AITD duration, and zonulin were analyzed. ResultsHT patients exhibited lower α4β7 and higher α4β1 expression on B cells compared to healthy controls and GD patients. While α4β7 was predominant on circulating B cells, the dominant integrin expressed on intrathyroidal B cells varied with specific thyroid diseases. In GD patients, α4β7 and α4β1 expression on circulating B cells correlated positively and negatively with thyroid function and thyroid stimulating immunoglobulins (TSI) levels, respectively. Intrathyroidal α4β1+ B cells positively correlated with TSH levels in HT patients. Additionally, serum zonulin was elevated in HT patients, and intrathyroidal α4β7+ B cells and α4β1+ B cells correlated negatively and positively with zonulin levels, respectively. Integrin αEβ7 on B cells showed no significant association with AITD. ConclusionIntegrins expressed on B cells potentially play a role in the pathogenesis of AITD and might serve as immune biomarkers for the disease.

A pilot study to identify blood-based markers associated with response to treatment with Vedolizumab in patients with Inflammatory Bowel Disease.

The inflammatory bowel diseases (IBD) known as Crohn's disease (CD) and ulcerative colitis (UC) are chronic inflammatory diseases of the gastrointestinal tract believed to arise because of an imbalance between the epithelial, immune and microbial systems. It has been shown that biological differences (genetic, epigenetic, microbial, environmental, etc.) exist between patients with IBD, with multiple risk factors been associated with disease susceptibility and IBD-related phenotypes (e.g. disease location). It is also known that there is heterogeneity in terms of response to therapy in patients with IBD, including to biological therapies that target very specific biological pathways (e.g. TNF-alpha signaling, IL-23R signaling, immune cell trafficking, etc.). It is hypothesized that the better the match between the biology targeted by these advanced therapies and the predominant disease-associated pathways at play in each patient will favor a beneficial response. The aim of this pilot study was to identify potential biological differences associated with differential treatment response to the anti α4β7 integrin therapy known as Vedolizumab. Our approach was to measure a broad range of analytes in the serum of patients prior to initiation of therapy and at the first clinical assessment visit, to identify potential markers of biological differences between patients at baseline and to see which biomarkers are most affected by treatment in responders. Our focus on early clinical response was to study the most proximal effects of therapy and to minimize confounders such as loss of response that occurs further distal to treatment initiation. Specifically, we performed targeted analyses of >150 proteins and metabolites, and untargeted analyses of >1100 lipid entities, in serum samples from 92 IBD patients (42 CD, 50 UC) immediately prior to initiation of therapy with vedolizumab (baseline samples) and at their first clinical assessment (14-week samples). We found lower levels of SDF-1a, but higher levels of PDGF-ββ, lactate, lysine, phenylalanine, branched chain amino acids, alanine, short/medium chain acylcarnitines, and triglycerides containing myristic acid in baseline serum samples of responders as compared to non-responders. We also observed an increase in serum levels of CXCL9 and citrate, as well as a decrease in IL-10, between baseline and week 14 samples. In addition, we observed that a group of metabolites and protein analytes was strongly associated with both treatment response and BMI status, although BMI status was not associated with treatment response.

CCR2 cooperativity promotes hematopoietic stem cell homing to the bone marrow.

Cross-talk between hematopoietic stem and progenitor cells (HSPCs) and bone marrow (BM) cells is critical for homing and sustained engraftment after transplantation. In particular, molecular and physical adaptation of sinusoidal endothelial cells (ECs) promote HSPC BM occupancy; however, signals that govern these events are not well understood. Extracellular vesicles (EVs) are mediators of cell-cell communication crucial in shaping tissue microenvironments. Here, we demonstrate that integrin α4β7 on murine HSPC EVs targets uptake into ECs. In BM ECs, HSPC EVs induce up-regulation of C-C motif chemokine receptor 2 (CCR2) ligands that synergize with CXCL12-CXCR4 signaling to promote BM homing. In nonirradiated murine models, marrow preconditioning with HSPC EVs or recombinant CCR2 ligands improves homing and early graft occupancy after transplantation. These findings identify a role for HSPC EVs in remodeling ECs, newly define CCR2-dependent graft homing, and inform novel translational conditioning strategies to improve HSPC transplantation.

Changes in monocyte subsets in volunteers who received an oral wild-type Salmonella Typhi challenge and reached typhoid diagnosis criteria.

An oral Controlled Human Infection Model (CHIM) with wild-type S. Typhi was re-established allowing us to explore the development of immunity. In this model, ~55% of volunteers who received the challenge reached typhoid diagnosis criteria (TD), while ~45% did not (NoTD). Intestinal macrophages are one of the first lines of defense against enteric pathogens. Most organs have self-renewing macrophages derived from tissue-resident progenitor cells seeded during the embryonic stage; however, the gut lacks these progenitors, and all intestinal macrophages are derived from circulating monocytes. After infecting gut-associated lymphoid tissues underlying microfold (M) cells, S. Typhi causes a primary bacteremia seeding organs of the reticuloendothelial system. Following days of incubation, a second bacteremia and clinical disease ensue. S. Typhi likely interacts with circulating monocytes or their progenitors in the bone marrow. We assessed changes in circulating monocytes after CHIM. The timepoints studied included 0 hours (pre-challenge) and days 1, 2, 4, 7, 9, 14, 21 and 28 after challenge. TD participants provided extra samples at the time of typhoid diagnosis, and 48-96 hours later (referred as ToD). We report changes in Classical Monocytes -CM-, Intermediate Monocytes -IM- and Non-classical Monocytes -NCM-. Changes in monocyte activation markers were identified only in TD participants and during ToD. CM and IM upregulated molecules related to interaction with bacterial antigens (TLR4, TLR5, CD36 and CD206). Of importance, CM and IM showed enhanced binding of S. Typhi. Upregulation of inflammatory molecules like TNF-α were detected, but mechanisms involved in limiting inflammation were also activated (CD163 and CD354 downregulation). CM upregulated molecules to interact/modulate cells of the adaptive immunity, including T cells (HLA-DR, CD274 and CD86) and B cells (CD257). Both CM and IM showed potential to migrate to the gut as integrin α4β7 was upregulated. Unsupervised analysis revealed 7 dynamic cell clusters. Five of these belonged to CM showing that this is the main population activated during ToD. Overall, we provide new insights into the changes that diverse circulating monocyte subsets undergo after typhoid diagnosis, which might be important to control this disease since these cells will ultimately become intestinal macrophages once they reach the gut.

Mucosal signatures of pathogenic T cells in HLA-B*27+ anterior uveitis and axial spondyloarthritis.

HLA-B*27 was one of the first HLA alleles associated with an autoimmune disease, i.e., axial spondyloarthritis (axSpA) and acute anterior uveitis (B27AAU), which cause joint and eye inflammation, respectively. Gastrointestinal inflammation has been suggested as a trigger of axSpA. We recently identified a bacterial peptide (YeiH) that can be presented by HLA-B*27 to expanded public T cell receptors in the joint in axSpA and the eye in B27AAU. While YeiH is present in enteric microbiota and pathogens, additional evidence that pathogenic T cells in HLA-B*27-associated autoimmunity may have had a prior antigenic encounter within the gastrointestinal tract remains lacking. Here, we analyzed ocular, synovial, and blood T cells in B27AAU and axSpA, showing that YeiH-specific CD8+ T cells express a mucosal gene set and surface proteins consistent with intestinal differentiation, including CD161, integrin α4β7, and CCR6. In addition, we found an expansion of YeiH-specific CD8+ T cells in axSpA and B27AAU blood compared with that from individuals acting as healthy controls, whereas influenza-specific CD8+ T cells were equivalent across groups. Finally, we demonstrated the dispensability of TRBV9 for antigen recognition. Collectively, our data suggest that, in HLA-B27-associated autoimmunity, early antigen exposure and differentiation of pathogenic CD8+ T cells may occur in enteric organs.

The integrin receptor beta7 subunit mediates airway remodeling and hyperresponsiveness in allergen exposed mice

BackgroundFibroblast differentiation to a myofibroblast phenotype is a feature of airway remodeling in asthma. Lung fibroblasts express the integrin receptor α4β7 and fibronectin induces myofibroblast differentiation via this receptor.ObjectivesTo investigate the role of the β7 integrin receptor subunit and α4β7 integrin complex in airway remodeling and airway hyperresponsiveness (AHR) in a murine model of chronic allergen exposure.MethodsC57BL/6 wild type (WT) and β7 integrin null mice (β7 -/-) were sensitized (days 1,10) and challenged with ovalbumin (OVA) three times a week for one or 4 weeks. Similar experiments were performed with WT mice in the presence or absence of α4β7 blocking antibodies. Bronchoalveolar (BAL) cell counts, AHR, histological evaluation, soluble collagen content, Transforming growth factor-β (TGFβ) and Interleukin-13 (IL13) were measured. Phenotype of fibroblasts cultured from WT and β7 -/- saline (SAL) and OVA treated mice was evaluated.ResultsEosinophil numbers were similar in WT vs β7-/- mice. Prolonged OVA exposure in β7-/- mice was associated with reduced AHR, lung collagen content, peribronchial smooth muscle, lung tissue TGFβ and IL13 expression as compared to WT. Similar findings were observed in WT mice treated with α4β7 blocking antibodies. Fibroblast migration was enhanced in response to OVA in WT but not β7 -/- fibroblasts. α-SMA and fibronectin expression were reduced in β7-/- fibroblasts relative to WT.ConclusionsThe β7 integrin subunit and the α4β7 integrin complex modulate AHR and airway remodeling in a murine model of allergen exposure. This effect is, at least in part, explained by inhibition of fibroblast activation and is independent of eosinophilic inflammation.

Real-life effectiveness and safety of vedolizumab in moderate-to-severe ulcerative colitis: A single-center experience in Northern China.

Vedolizumab (VDZ), a monoclonal antibody to α4β7 integrin, is available for patients with moderate-to-severe ulcerative colitis (UC). This study planned to assess the real-world effectiveness and safety of VDZ for UC patients in Northern China. We enrolled patients with moderate-to-severe UC who underwent VDZ induction therapy from March 2021 to November 2022 at the Affiliated Hospital of Qingdao University. The primary outcome was clinical remission at weeks 14 and 52 after the initial VDZ therapy. Overall adverse events and risk factors associated with loss of response (LOR) were also evaluated. Seventy-three UC patients receiving VDZ therapy were included in this study. The rates of clinical response, clinical remission, and steroid-free clinical remission were 69.9%, 39.7%, and 34.2% at week 14 and 90.5%, 66.7%, and 64.4% at week 52, respectively. The mucosal remission rates were 37.5% (18/48) at week 14 ± 8 and 27.3% (9/33) at week 52 ± 16, while only 2 and 3 patients achieved mucosal healing at weeks 14 ± 8 and 52 ± 16, respectively. Of the UC patients, 23.3% experienced adverse events associated with VDZ, most of which were mild and self-limiting. Until the last follow-up, 37 of 73 UC patients experienced LOR during the maintenance period. Patients with a higher ulcerative colitis endoscopic severity index (UCEIS), partial Mayo scores (PMS), or hemoglobin below 120 g/L at baseline were more likely to experience LOR after VDZ induction therapy. VDZ is an effective and safe agent for patients with moderate-to-severe UC in Northern China. A high baseline UCEIS, PMS, or hemoglobin < 120 g/L may be an independent risk factor for LOR during the maintenance period.

Vedolizumab in the treatment of Crohn's disease: A promising therapeutic approach

AbstractCrohn's disease (CD) is a chronic and debilitating inflammatory bowel disease that affects millions of individuals worldwide. Despite the availability of various treatment options, a significant number of patients do not achieve remission or experience adverse effects with conventional therapies. Vedolizumab, a novel therapeutic agent, has emerged as a promising approach in the management of CD. Despite improvements in treatment choices, there is still a demand for medicines that are efficient and well‐tolerated. Vedolizumab, a monoclonal antibody targeting α4β7 integrin, has emerged as a promising therapeutic approach for the treatment of CD. The review aims to provide a summary of vedolizumab, current treatment options, impact of vedolizumab on the patient's quality of life, mechanism of action, clinical effectiveness, safety and efficacy of vedolizumab, potential side effects or risks associated with vedolizumab therapy, and potential predictors. Furthermore, we investigate limitations and challenges associated with vedolizumab and possible future developments and medical implications. This review provides a comprehensive examination of the present data supporting vedolizumab as a possible treatment option for CD, highlighting its benefits and outlining prospective directions for future study and clinical practice improvement.

The protective roles of integrin α4β7 and Amphiregulin-expressing innate lymphoid cells in lupus nephritis

Type 2 innate lymphoid cells (ILC2s) have emerged as key regulators of the immune response in renal inflammatory diseases such as lupus nephritis. However, the mechanisms underlying ILC2 adhesion and migration in the kidney remain poorly understood. Here, we revealed the critical role of integrin α4β7 in mediating renal ILC2 adhesion and function. We found that integrin α4β7 enables the retention of ILC2s in the kidney by binding to VCAM-1, E-cadherin, or fibronectin on structural cells. Moreover, integrin α4β7 knockdown reduced the production of the reparative cytokine amphiregulin (Areg) by ILC2s. In lupus nephritis, TLR7/9 signaling within the kidney microenvironment downregulates integrin α4β7 expression, leading to decreased Areg production and promoting the egress of ILC2s. Notably, IL-33 treatment upregulated integrin α4β7 and Areg expression in ILC2s, thereby enhancing survival and reducing inflammation in lupus nephritis. Together, these findings highlight the potential of targeting ILC2 adhesion as a therapeutic strategy for autoimmune kidney diseases.

MAdCAM-1 co-stimulation combined with retinoic acid and TGF-β induces blood CD8+ T cells to adopt a gut CD101+ TRM phenotype

Resident memory T cells (TRMs) help control local immune homeostasis and contribute to tissue protective immune responses. The local cues that guide their differentiation and localization are poorly defined. We demonstrate that MAdCAM-1, a ligand for the gut homing receptor α4β7 integrin, in the presence of retinoic acid and TGF-β provide a costimulatory signal that induces blood CD8+ T cells to adopt a TRM -like phenotype. These cells express CD103 (integrin αE) and CD69, the two major TRM cell surface markers, along with CD101. They also express CCR5, CCR9 and α4β7, three receptors associated with gut homing. A subset also express E-cadherin, a ligand for αEβ7. Fluorescent lifetime imaging indicated an αEβ7 and E-cadherin cis interaction on the plasma membrane. This report advances our understanding of the signals that drive the differentiation of CD8+ T cells into TRMs and provides a means to expand these cells in vitro, thereby affording an avenue to generate more effective tissue specific immunotherapies.

Selective Targeting of α4β7/MAdCAM-1 Axis Suppresses Fibrosis Progression by Reducing Proinflammatory T Cell Recruitment to the Liver.

Integrin α4β7+ T cells perpetuate tissue injury in chronic inflammatory diseases, yet their role in hepatic fibrosis progression remains poorly understood. Here, we report increased accumulation of α4β7+ T cells in the liver of people with cirrhosis relative to disease controls. Similarly, hepatic fibrosis in the established mouse model of CCl4-induced liver fibrosis was associated with enrichment of intrahepatic α4β7+ CD4 and CD8 T cells. Monoclonal antibody (mAb)-mediated blockade of α4β7 or its ligand mucosal addressin cell adhesion molecule (MAdCAM)-1 attenuated hepatic inflammation and prevented fibrosis progression in CCl4-treated mice. Improvement in liver fibrosis was associated with a significant decrease in the infiltration of α4β7+ CD4 and CD8 T cells, suggesting that α4β7/MAdCAM-1 axis regulates both CD4 and CD8 T cell recruitment to the fibrotic liver, and α4β7+ T cells promote hepatic fibrosis progression. Analysis of hepatic α4β7+ and α4β7- CD4 T cells revealed that α4β7+ CD4 T cells were enriched for markers of activation and proliferation, demonstrating an effector phenotype. The findings suggest that α4β7+ T cells play a critical role in promoting hepatic fibrosis progression, and mAb-mediated blockade of α4β7 or MAdCAM-1 represents a promising therapeutic strategy for slowing hepatic fibrosis progression in chronic liver diseases.

Dysfunctional intestinal microvascular endothelial cells: Insights and therapeutic implications in gastrointestinal inflammation.

The intestinal microvascular endothelium plays a crucial role in orchestrating host responses to inflammation within the gastrointestinal tract. This review delves into the unique aspects of intestinal microvascular endothelial cells, distinct from those of larger vessels, in mediating leukocyte recruitment, maintaining barrier integrity, and regulating angiogenesis during inflammation. Specifically, their role in the pathogenesis of inflammatory bowel diseases, where dysregulated endothelial functions contribute to the disease progression, is reviewed. Furthermore, this review discusses the isolation technique for these cells and commonly used adhesion molecules for in vitro and in vivo experiments. In addition, we reviewed the development and therapeutic implications of a biologic agent targeting the interaction between α4β7 integrin on T lymphocytes and mucosal addressin cellular adhesion molecule-1 on gut endothelium. Notably, vedolizumab, a humanized monoclonal antibody against α4β7 integrin, has shown promising outcomes in inflammatory bowel diseases and other gastrointestinal inflammatory conditions, including chronic pouchitis, immune checkpoint inhibitor-induced colitis, and acute cellular rejection post-intestinal transplantation.

Dysregulation of CD4+ and CD8+ resident memory T, myeloid, and stromal cells in steroid-experienced, checkpoint inhibitor colitis

BackgroundColitis caused by checkpoint inhibitors (CPI) is frequent and is treated with empiric steroids, but CPI colitis mechanisms in steroid-experienced or refractory disease are unclear.MethodsUsing colon biopsies and blood from...

Evaluating the Serum Levels of CCL17, CCL22, and CCL28 Chemokines and the Gene Expression of α4β1 and α4β7 Integrins in Patients With Allergic Rhinitis

Allergic rhinitis (AR) is a chronic inflammatory disease involving the nasal mucosa. Leukocytes recruitment to the inflammation sites is controlled by chemokines, cytokines, and adhesion molecules. Retinoic acid (RA), a vitamin A metabolite, plays an essential role in mucosal immunity and the production of inflammatory cytokines and chemokines. This study intended to evaluate the serum levels of RA, CCL17, CCL22, CCL28, and the mRNA expression levels of α4, β1, and β7 integrins in AR patients compared to healthy subjects. Peripheral blood was collected from 37 patients with AR and 30 age- and gender-matched healthy individuals. Serum levels of RA, CCL17, CCL22, and CCL28 were measured by the enzyme-linked immunosorbent assay (ELISA) technique, and the mRNA expression levels for α4, β1, and β7 integrins were assessed using the quantitative real-time PCR method. Our results showed that the serum levels of CCL22 and CCL28 chemokines are significantly higher in the AR group compared to the healthy controls (P&lt;0.01). However, the gene expression of the β1 integrin in the AR group was significantly lower than that of the control group (P&lt;0.001). Besides, there was a positive association between serum RA and CCL17 levels in patients (P&lt;0.0001, r=0.6). In conclusion, increased serum levels of CCL22 and CCL28 chemokines, as well as decreased gene expression of β1 integrin in AR patients, may contribute to the pathogenesis and/or exacerbation of AR.

Vedolizumab Does Not Affect Antibody Secreting Cell Recruitment to the Lactating Mammary Gland of Mothers With Inflammatory Bowel Disease.

Lay Summary Despite a known role for α4β7 and MAdCAM-1 for the recruitment of antibody secreting cells to the lactating mammary gland, vedolizumab which targets integrin α4β7 did not lower breastmilk IgA in lactating mothers with IBD receiving the drug. It is likely that antibody secreting cells alternatively employ α4β1 to arrest on VCAM-1 also expressed by the lactating mammary gland.

VEDOLIZUMAB DOES NOT ALTER IMMUNOGLOBULIN LEVELS IN BREASTMILK OF MOTHERS WITH IBD

Abstract Diarrheal diseases are a major cause of infant mortality worldwide. Breastfeeding helps prevent such diseases by passive transfer of maternal antibodies against gastrointestinal pathogens previously encountered by the mother. The antibody secreting cells (ASC) that populate the lactating mammary gland (LMG) are educated in gastrointestinal lymphoid tissues, thus they express integrin a4b7. To recruit these ASC, the LMG expresses MAdCAM-1 and CCL28. Vedolizumab (vedo) blocks a combinatorial epitope on integrin a4b7, interfering with lymphocyte recruitment to the gut. Given the shared homing determinants between the gut and LMG, we investigated whether vedo might interfere with ASC trafficking to the LMG, therefore decreasing immunoglobulin (Ig) levels in breast milk. We measured Ig levels by ELISA in cryopreserved breast milk from mothers enrolled in Mommy’s Milk biorepository at the University of California, San Diego without and with Ulcerative Colitis(UC) or Crohn’s Disease(CD) and lactating mothers with UC and CD treated with vedo for more than 18 months. Milk samples were collected between 1 month and 15.45 months after childbirth. The levels of secretory IgA (SIgA) in breast milk of mothers without IBD (n=45) was not different from those of mothers with CD not on vedo (n=15) (301 ± 147 ug/mL vs. 322 ± 207 ug/mL). However, milk SIgA from mothers with UC not on vedo (n=7) were lower than non-IBD controls (213 ± 149 ug/mL vs. 301 ± 147ug/mL, p&amp;lt;0.01). We then compared milk SIgA from patients with CD and UC treated with vedo (CD: n= 9; 256 ± 80ug/mL, UC: n=10; 283 ± 87 ug/mL) with those from non-IBD controls (n=45; 301 ± 147ug/mL) and found no differences. Similarly, SIgA levels were not different between CD with or without vedo (256 ± 80 ug/mL vs. 322 ± 207 ug/mL) and as compared with non-IBD controls SIgA in patients with UC with vedo were unexpectedly higher than UC without vedo (283 ±87 ug/mL vs 213 ± 149 ug/mL, p&amp;lt;0.05). The levels of secretory IgM (SIgM) in milk were not different between mothers with UC or CD treated with vedo compared with non-IBD controls (65 ± 34 ug/mL, 69 ± 32 ug/mL, and 56 ± 37 ug/mL, respectively). Similarly, no significant difference was seen between patients with UC or CD not treated with vedo compared with the non-IBD controls (58±26 ug/mL, and 46 ± 24 ug/mL respectively). We conclude that vedo does not reduce SIgA nor SIgM levels in lactating mothers with IBD. We speculate that the higher SIgA in patients with UC treated with vedo is due to the small sample size. Vedo does not interfere with passive immunity during the lactation period, thus ASC must be able to use another integrin to arrest on microvessels of the LMG during the final stages of pregnancy.