Qian Yuan

Chemokine CXCL10 Promotes Atherogenesis by Modulating the Local Balance of Effector and Regulatory T Cells

Background— Studies to define the overall contribution of lymphocytes to lesion formation in atherosclerosis-susceptible mice have demonstrated relatively subtle effects; the use of lymphocyte-deficient mice, however, compromises both the effector and regulatory arms of the immune system. Here, we tested the hypothesis that deletion of CXCL10 (IP-10), a chemokine specific for effector T cells that has been localized within atherosclerotic lesions, would significantly inhibit atherogenesis. Methods and Results— Compound deficient Apoe−/−/Cxcl10−/− mice fed a Western-style diet for either 6 or 12 weeks demonstrated significant reductions in atherogenesis as compared with Apoe−/− controls, as assessed by both aortic en face and cross-sectional analyses. Immunohistochemical studies revealed a decrease in the accumulation of CD4+ T cells, whereas quantitative polymerase chain reaction analysis of lesion-rich aortic arches demonstrated a marked reduction in mRNA for CXCR3, the CXCL10 chemokine receptor. Although overall T-cell accumulation was diminished significantly, we found evidence to suggest that regulatory T-cell (Treg) numbers and activity were enhanced, as assessed by increased message for the Treg-specific marker Foxp3, as well as increases in immunostaining for the Treg-associated cytokines interleukin-10 and transforming growth factor-β1. We also documented naturally occurring Treg cells in human atherosclerotic lesions. Conclusions— We provide novel evidence for a functional role for the effector T-cell chemoattractant CXCL10 in atherosclerotic lesion formation by modulating the local balance of the effector and regulatory arms of the immune system.

CCR4-dependent regulatory T cell function in inflammatory bowel disease

Inflammatory bowel disease (IBD) is an idiopathic inflammatory disease of the intestine. CD4+ T lymphocytes play an important role in both initiating and regulating intestinal inflammatory immune responses. CD4+CD25+CD45RBlow regulatory T (T reg) cells are capable of preventing the development of colitis in a mouse model of IBD. The precise mechanism of T reg cell–mediated prevention of colitis in this model is unclear, and the role of chemokine receptors in the trafficking and function of T reg cells in this model has not been determined. We examined the role of the chemokine receptor CCR4 in in vivo trafficking and suppressive function of T reg cells in a mouse adoptive transfer model of IBD. CCR4-deficient T reg cells failed to accumulate in the mesenteric lymph nodes (MLNs) at early time points (2–5 d) after adoptive transfer, resulting in a failure to suppress the generation of pathogenic T cells and the development of colitis. Moreover, although CCR4-deficent T cells had equivalent in vitro suppressive activity and accumulated in MLNs at later time points (42–56 d), they were unable to suppress colitis. Our study demonstrates that CCR4 plays an important role in T reg cell trafficking in LNs and that this is critical for T reg cell suppressive function in vivo.

Innate immunity of the gut: mucosal defense in health and disease.

The intestine is an important immune organ consisting of a complex cellular network, secreted peptides and proteins and other host defenses. Innate immunity plays a central role in intestinal immune defense against invading pathogens. It also serves as a bridge to the activation of the adaptive immune system. Pattern recognition molecules of microorganisms are an essential component for identifying invading pathogens. Toll-like receptors (TLRs), CARD15/NOD2 and scavenger receptors all serve as the pattern recognition receptors in the innate immune defense system. Secreted bactericidal peptides or defensins produced by the intestinal epithelia represent another crucial element of innate mucosal immune defense. Mutations in pattern recognition receptors and dysfunction of secretory bactericidal peptides may impair host immune defenses leading to an invasion of pathogens resulting in chronic inflammation of the gut. This review updates our current understanding of innate immunity of the gastrointestinal tract.

Shortcomings of the Inflammatory Bowel Disease Serology 7 Panel

OBJECTIVE: The goal was to compare the predictive values of the Prometheus Inflammatory Bowel Disease (IBD) Serology 7 (IBD7) panel (Prometheus Laboratories, San Diego, CA) with the predictive values of routine blood tests in a population of children referred for initial evaluation of suspected IBD. METHODS: Medical records of pediatric patients referred for evaluation of IBD for whom IBD7 testing was performed at Prometheus Laboratories between January 2006 and November 2008 were reviewed. Patients underwent diagnosis by pediatric gastroenterologists on the basis of clinical, radiologic, endoscopic, and pathologic evaluations. RESULTS: A total of 394 records were identified. We excluded 90 records on the basis of age of >21 years, previous diagnosis of IBD, or unclear diagnosis. The prevalence of IBD in this cohort was 38%. The sensitivity, specificity, positive predictive value, negative predictive value, and κ value for the serological panel were 67%, 76%, 63%, 79%, and 42%, respectively, compared with values for a combination of 3 abnormal routine laboratory test results of 72%, 94%, 85%, 79%, and 47%. The antiflagellin antibody assay, the newest assay added to the panel, had sensitivity of 50% and specificity of 53%. Repeat serological testing failed to produce consistent results for 4 of 10 patients. CONCLUSION: Despite its recent inclusion of the antiflagellin assay, the IBD7 panel has lower predictive values than routine laboratory tests in pediatric screening for IBD.

Membrane-bound eotaxin-3 mediates eosinophil transepithelial migration in IL-4-stimulated epithelial cells.

Epithelial cells play an important role in orchestrating mucosal immune responses. In allergic‐type inflammation, epithelial cells control the recruitment of eosinophils into the mucosa. Th2‐type cytokine‐driven release of eosinophil‐active chemokines from epithelial cells directs eosinophil migration into the mucosal epithelium. CCR3, the main eosinophil chemokine receptor, regulates this process; however, the respective contribution of individual CCR3 ligands in eosinophil transepithelial migration is less well understood. Using an in vitro transepithelial chemotaxis system, we found that eotaxin‐3 produced by IL‐4‐stimulated airway epithelial cells and CCR3 on eosinophils exclusively mediate eosinophil transepithelial migration. Eotaxin‐3 protein levels were also increased in the nasal mucosal epithelium recovered from allergic patients as compared to non‐allergic patients. Surprisingly, eotaxin‐3 in IL‐4‐stimulated airway epithelial cells was predominantly cell surface bound, and the cell surface form was critical for eosinophil transepithelial migration. Eotaxin‐3 cell surface association was partially glycosaminoglycan (GAG) dependent, but was completely protein dependent, suggesting that eotaxin‐3 associates with both GAG and cell surface proteins. We thus provide evidence that cell surface‐associated eotaxin‐3 is the critical IL‐4‐dependent chemotactic signal mediating eosinophil transepithelial migration in the setting of allergic inflammation.

Tethered confocal endomicroscopy capsule for diagnosis and monitoring of eosinophilic esophagitis

Eosinophilic esophagitis (EoE) is an allergic condition that is characterized by eosinophils infiltrating the esophageal wall. The treatment of the disease may require multiple follow up sedated endoscopies and biopsies to confirm elimination of eosinophils. These procedures are expensive, time consuming, and may be difficult for patients to tolerate. Here we report on the development of a confocal microscopy capsule for diagnosis and monitoring of EoE. The swallowable capsule implements a high-speed fiber-based reflectance confocal microscopy technique termed Spectrally Encoded Confocal Microscopy (SECM). SECM scans the sample in one dimension without moving parts by using wavelength swept source illumination and a diffraction grating at the back plane of the objective lens. As the wavelength of the source is tuned, the SECM optics within the 7 x 30 mm capsule are rotated using a driveshaft enclosed in a 0.8 mm flexible tether. A single rotation of the optics covered a field of view of 22 mm x 223 µm. The lateral and axial resolutions of the device were measured to be 2.1 and 14 µm, respectively. Images of Acetic Acid stained swine esophagus obtained with the capsule ex vivo and in vivo clearly showed squamous epithelial nuclei, which are smaller and less reflective than eosinophils. Imaging of esophageal biopsies from EoE patients ex vivo demonstrated the capability of this technology to visualize individual eosinophils. Based on the results of this study, we believe that this capsule will be a simpler and more effective device for diagnosing EoE and monitoring the therapeutic response of this disease.

Cesarean section and antibiotic use found to be associated with eosinophilic esophagitis

Eosinophilic esophagitis (EoE) is an emergent disease with unclear environmental causes. In the few studies of the epidemiology of EoE, male sex and white race have been identified as risk factors. A recent report suggested that cesarean section and early life antibiotic use may increase the risk of EoE, but other studies have not specifically looked at these factors, nor have they examined associations between early life gastrointestinal symptoms and EoE. The aim of this study was to investigate associations between EoE and dietary, environmental, and medical exposures during infancy. Subjects and controls ages 1-5 years old were recruited from the pediatric clinics at the Massachusetts General Hospital. EoE cases were identified by a systematic review of pediatric gastroenterology and allergy clinic visits (by International Classification of Diseases, Ninth Revision codes) between March 2011 and May 2012, and a review of all age-eligible endoscopy procedure visits between January 2008 and May 2012. A diagnosis of EoE was based on endoscopy findings of 15 eosinophils in any high-powered field on esophageal biopsy specimens while the subject was on adequate proton-pump inhibitor therapy ( 1 mg/kg/d for 6 weeks). Subjects were excluded if they had known eosinophilic gastroenteritis, inflammatory bowel disease, or any systemic hypereosinophilic syndromes. Control subjects were recruited from the Pediatric Ambulatory Care Clinic well-child and followup visits. This clinic has a comparable demographic profile to the specialty clinics, with a similar percentage of patients covered by state-assisted health insurance. Control subjects were excluded if they had symptoms suggestive of undiagnosed EoE, including feeding difficulty, frequent vomiting, frequent chest and/or abdominal pain, or dysphagia. Frequency matching of controls was performed for a family history of atopy and for sex. Approval for this study was given by the Massachusetts General Hospital Institutional Review Board. The parent of each subject completed a questionnaire at the time of a clinic visit or via electronic mail. The screening and study questionnaire included questions extracted from the International Study of Asthma and Allergies in Childhood study questionnaires. Study data were collected and managed by using REDCap electronic data capture tools hosted at Massachusetts General Hospital. Characteristics of subjects and controls were compared by the Fisher exact test for dichotomous variables and by the Mann-Whitney 2-sample statistic for continuous variables. Odds ratios (OR) were calculated by logistic regression. The only significant demographic difference between the groups was age; therefore, analyses were adjusted for age, and for the frequency matching variables (atopic family history and sex). To explore mediators of associations found, additional analyses of timing of dietary introduction were adjusted for history of formula intolerance, and analyses of mode of delivery and early life antibiotic use were adjusted for personal history of atopy. Calculations were done with STATA SE 11.2 (College Station, Texas). Twenty-five subjects with EoE and 74 controls were enrolled; 14 subjects were excluded because of symptoms that could be suggestive of undiagnosed EoE. Questionnaires were completed by 89% and 85% of approached subjects and controls, respectively. As seen in Table I, demographic characteristics of subjects and controls were similar, except that the subjects were younger (median 41 vs 51 months). The subjects with EoE were more frequently born by cesarean section than were the controls (60% vs 34%; P 1⁄4 .03) and had a significantly higher rate of antibiotic use in the first year of life (67% vs 33%; P 1⁄4 .004), differences that were significant when adjusting for age, family history of atopy, and sex. (Tables I and II). After also adjusting for a personal history of atopy, the subjects still had increased odds of antibiotic use in the first year of life (OR 3.61 [95% CI, 1.11e11.74]; P 1⁄4 .03), although the relationship with mode of delivery was no longer statistically significant (OR 2.69 [95% CI, 0.93e7.83]; P 1⁄4 .07). Patients with EoE reported a significantly higher frequency of signs and symptoms of gastrointestinal allergy early in life. Unexpectedly, lower gastrointestinal tract disease manifestations also were significantly associated with EoE. Specifically, the subjects with EoE had substantially higher rates of hematochezia (22% vs 4%; P 1⁄4 .02) and mucous in the stool (35% vs 7%; P 1⁄4 .002) during the first year of life, although the difference in hematochezia was no longer significant when adjusting for age, a family history of atopy, and sex (P 1⁄4 .07) (Table I). No significant differences were seen between groups on measures of breastfeeding; timing of first solid food introduction; or timing of introduction of dairy, concentrated egg, wheat, meats, corn, or peanuts. Small significant differences in timing of foods typically introduced later in infancy, including baked egg products, tree nuts, shellfish, and fish generally did not persist after adjusting for the use of hypoallergenic formula, although age of introduction of baked egg products and fish remained higher in the subjects than with the controls (see Tables E1 and E2 in this article’s Online Repository at www.jaci-inpractice.org). The aim of this study was to investigate the association between early life exposures with the later development of EoE. We found that cesarean delivery and antibiotic exposure in the first year of life were significantly associated with the development of EoE. The findings with regard to cesarean section and antibiotic use are of similar magnitude to another case-control study of EoE in children up to age 17 years old, despite the differences in ages. The mode of delivery has not otherwise been linked to EoE,

Longitudinal Perspective on Managing Refractory Eosinophilic Esophagitis

BACKGROUND One half to one third of the patients with eosinophilic esophagitis (EoE) do not achieve histological remission on initial treatment. We wondered whether these treatment failure patients are a distinct clinical subset. OBJECTIVE To analyze EoE treatment outcomes in a predominantly pediatric population. METHODS We reviewed 100 serial EoE cases at Massachusetts General Hospital starting from 2007. We defined histological remission as peak esophageal eosinophil count of less than 10/hpf. RESULTS Ninety-seven patients with EoE underwent initial treatments: 54 of 81 (67%) responded to dietary therapy, and 9 of 16 (56%) responded to topical glucocorticoids. Of the 34 who failed initial treatment, 24 underwent various second treatment regimens and 54% (13 of 24) responded. Eight of the remaining 11 who failed second treatment underwent additional treatments and 2 ultimately responded. The overall response rate by intent-to-treat analysis increased from 65% (63 of 97) with initial treatment to 78% (76 of 97) with rescue treatment, and further to 80% (78 of 97) with multiple treatments. On a per-protocol basis, the overall response rate was 93% (78 of 84); however, patients who failed the first 2 rounds of therapy had only a 20% response rate. Patients who responded to initial treatment were found to have more symptoms and endoscopic abnormalities. Comparison of patients who failed both initial and rescue therapy with those who responded to rescue therapy did not identify any differentiating clinical features. CONCLUSIONS More than half of the patients who failed initial EoE treatment could still achieve histological remission with individualized rescue treatments. No clinical features could predict response to rescue treatment.

Case records of the Massachusetts General Hospital. Case 27-2013. A 6.5-month-old boy with fever, rash, and cytopenias.

Dr. Sarita U. Patil (Medicine): A 6.5-month-old boy was admitted to this hospital because of fever, rash, and thrombocytopenia. The patient was well until the day before admission, when his mother noted bruising on both medial thighs, which she attributed to use of a jumping chair. On the morning of admission, she noted increased bruising on his thighs and “broken capillaries” on his cheeks and eyelids. On examination at another hospital, he was active and behaviorally appropriate. The rectal temperature was 37.4°C, the pulse 146 beats per minute, the respiratory rate 45 breaths per minute, and the oxygen saturation 100% while the patient was breathing ambient air. There were multiple scattered petechiae on the face, chest, and legs; the remainder of the examination was normal. Laboratory results are shown in Table 1. He was transferred to this hospital. The patient was active and developmentally normal. At 3 months of age, intermittent urticaria had developed when small amounts of a milk-based formula were given, mixed with breast milk. There was no history of trauma, epistaxis, gingival bleeding, or blood in the urine or stool. He was born to a primigravida by cesarean section because of preeclampsia, after full-term gestation. Immunizations were current, excluding influenza A (H1N1) and seasonal influenza vaccines. Acetaminophen had been administered for teething pain until 2 days before this presentation. He had no known allergies. He lived with his parents and two dogs, did not attend day care, and had no exposures to sick persons. A cousin of his mother had splenomegaly of unknown cause; there was no known family history of hematologic disorders. The vital signs and physical examination were unchanged. The ABO blood type was A, Rh-positive, with negative screening for antibodies to red cells. Blood levels of electrolytes, phosphorus, magnesium, urea nitrogen, direct and total bilirubin, glucose, amylase, and lipase were normal, as were the results of tests of coagulation and liver function; other test results are shown in Table 1. Anti-RhD immune globulin (referred to as anti-D) (550 μg [50 μg per kilogram of body weight]) was administered intravenously. Test results from the next day are shown in Table 1. Blood cultures drawn at the other hospital remained sterile, and the patient was discharged home.

Case 27-2013

Dr. Sarita U. Patil (Medicine): A 6.5-month-old boy was admitted to this hospital because of fever, rash, and thrombocytopenia. The patient was well until the day before admission, when his mother noted bruising on both medial thighs, which she attributed to use of a jumping chair. On the morning of admission, she noted increased bruising on his thighs and “broken capillaries” on his cheeks and eyelids. On examination at another hospital, he was active and behaviorally appropriate. The rectal temperature was 37.4°C, the pulse 146 beats per minute, the respiratory rate 45 breaths per minute, and the oxygen saturation 100% while the patient was breathing ambient air. There were multiple scattered petechiae on the face, chest, and legs; the remainder of the examination was normal. Laboratory results are shown in Table 1. He was transferred to this hospital. The patient was active and developmentally normal. At 3 months of age, intermittent urticaria had developed when small amounts of a milk-based formula were given, mixed with breast milk. There was no history of trauma, epistaxis, gingival bleeding, or blood in the urine or stool. He was born to a primigravida by cesarean section because of preeclampsia, after full-term gestation. Immunizations were current, excluding influenza A (H1N1) and seasonal influenza vaccines. Acetaminophen had been administered for teething pain until 2 days before this presentation. He had no known allergies. He lived with his parents and two dogs, did not attend day care, and had no exposures to sick persons. A cousin of his mother had splenomegaly of unknown cause; there was no known family history of hematologic disorders. The vital signs and physical examination were unchanged. The ABO blood type was A, Rh-positive, with negative screening for antibodies to red cells. Blood levels of electrolytes, phosphorus, magnesium, urea nitrogen, direct and total bilirubin, glucose, amylase, and lipase were normal, as were the results of tests of coagulation and liver function; other test results are shown in Table 1. Anti-RhD immune globulin (referred to as anti-D) (550 μg [50 μg per kilogram of body weight]) was administered intravenously. Test results from the next day are shown in Table 1. Blood cultures drawn at the other hospital remained sterile, and the patient was discharged home.