Myo1f has an essential role in γδT intraepithelial lymphocyte adhesion and migration.

γδT intraepithelial lymphocyte represents up to 60% of the small intestine intraepithelial compartment. They are highly migrating cells and constantly interact with the epithelial cell layer and lamina propria cells. This migratory phenotype is related to the homeostasis of the small intestine, the control of bacterial and parasitic infections, and the epithelial shedding induced by LPS. Here, we demonstrate that Myo1f participates in the adhesion and migration of intraepithelial lymphocytes. Using long-tailed class I myosins KO mice, we identified the requirement of Myo1f for their migration to the small intestine intraepithelial compartment. The absence of Myo1f affects intraepithelial lymphocytes' homing due to reduced CCR9 and α4ß7 surface expression. In vitro, we confirm that adhesion to integrin ligands and CCL25-dependent and independent migration of intraepithelial lymphocytes are Myo1f-dependent. Mechanistically, Myo1f deficiency prevents correct chemokine receptor and integrin polarization, leading to reduced tyrosine phosphorylation which could impact in signal transduction. Overall, we demonstrate that Myo1f has an essential role in the adhesion and migration in γδT intraepithelial lymphocytes.

Irinotecan-induced intestinal mucositis in mice: a histopathological study.

PURPOSE: Intestinal mucositis is an important adverse effect of antineoplastic therapy, which remains without adequate treatment. The present study aimed to carry out a complete evaluation of the histopathological changes during irinotecan-induced intestinal mucositis, using the protocol most found in the pharmacological reports nowadays to better understand irinotecan toxicity and support future studies on drug discovery. METHODS: Intestinal mucositis was induced by treating swiss mice for 4 days with irinotecan (75 mg/kg, i.p.). After 72 h post irinotecan, the mice were sacrificed and the small intestine and colon were excised to performed histological analysis by stained tissue with hematoxylin/eosin (H&E). RESULTS: Histoarchitecture loss, villus/crypt ratio reduction, atrophy of the muscular layer, hypertrophy in the submucosal and mucous layers, ruptures in the epithelium, as well as extent cellular infiltrate and presence of micro abscesses and the fusion of the crypts were observed in the histological analysis. Moreover, duodenum and colon had increased intraepithelial lymphocytes and mitotic figures. However, submucosal ganglia were decreased in the duodenum and increased in the colon. CONCLUSIONS: The data obtained in the present study provides new evidence that irinotecan-induced intestinal mucositis highly affects small intestine and colon, further contributing to establish criteria in light of the histopathological changes induced by irinotecan during intestinal mucositis and facilitating inter-study comparisons.

More fuel to the fire: some patients with non-celiac self-reported wheat sensitivity exhibit adaptive immunological responses in duodenal mucosa.

BACKGROUND: In contrast to the well-characterized Celiac Disease (CD), the clinical scenarios encompassed by the non-celiac self-reported wheat sensitivity (NCSRWS) might be related to different antigens that trigger distinct immune-inflammatory reactions. Although an increased number of intestinal intraepithelial lymphocytes is observed at the inception of both diseases, the subsequent immunopathogenic pathways seem to be different. We aimed to describe the cytokine profile observed in the duodenal mucosa of patients with NCSRWS. METHODS: In a blind, cross-sectional study, we included duodenal biopsies from 15 consecutive untreated patients with active CD, 9 individuals with NCSRWS and 10 subjects with dyspepsia without CD and food intolerances. Immunohistochemistry and flow-cytometry were used to determine the presence of pro-inflammatory cytokine expressing monocytes and monocyte-derived dendritic cells involved in innate immune activation, cytokine-driven polarization and maintenance of Th1 and Th17/Th 22, and anti-inflammatory/profibrogenic cytokines. RESULTS: The percentage of cells expressing all tested cytokines in the lamina propria and the epithelium was higher in CD patients than in the control group. Cytokines that induce and maintain Th1 and Th17 polarization were higher in CD than in NCSRWS and controls, also were higher in NCSRWS compared to controls. Similar differences were detected in the expression of IL-4 and TGF-1, while IL-10-expressing cells were lower in NCSRWS patients than in controls and CD subjects. CONCLUSIONS: NCSRWS patients exhibit components of both, innate and adaptive immune mechanisms but to a lesser extent compared to CD.

Immunobiotic Lactobacillus strains reduce small intestinal injury induced by intraepithelial lymphocytes after Toll-like receptor 3 activation.

OBJECTIVE: Intestinal intraepithelial lymphocytes (IELs) play critical roles in disrupting epithelial homeostasis after Toll-like receptor (TLR)-3 activation with genomic rotavirus dsRNA or the synthetic dsRNA analog poly(I:C). The capacity of immunobiotic Lactobacillus rhamnosus CRL1505 (Lr1505) or Lactobacillus plantarum CRL1506 (Lp1506) to beneficially modulate IELs response after TLR3 activation was investigated in vivo using a mice model. RESULTS: Intraperitoneal administration of poly(I:C) induced inflammatory-mediated intestinal tissue damage through the increase of inflammatory cells (CD3(+)NK1.1(+), CD3(+)CD8αα(+), CD8αα(+)NKG2D(+)) and pro-inflammatory mediators (TNF-α, IL-1ß, IFN-γ, IL-15, RAE1, IL-8). Increased expression of intestinal TLR3, MDA5, and RIG-I was also observed after poly(I:C) challenge. Treatment with Lr1505 or Lp1506 prior to TLR3 activation significantly reduced the levels of TNF-α, IL-15, RAE1, and increased serum and intestinal IL-10. Moreover, CD3(+)NK1.1(+), CD3(+)CD8αα(+), and CD8αα(+)NKG2D(+) cells were lower in lactobacilli-treated mice when compared to controls. The immunomodulatory capacities of lactobacilli allowed a significant reduction of intestinal tissue damage. CONCLUSIONS: This work demonstrates the reduction of TLR3-mediated intestinal tissue injury by immunobiotic lactobacilli through the modulation of intraepithelial lymphocytes response. It is a step forward in the understanding of the cellular mechanisms involved in the antiviral capabilities of immunobiotic strains.

Clinical utility of counting intraepithelial lymphocytes in celiac disease intestinal mucosa / Utilidad clínica del recuento de linfocitos intraepiteliales en la mucosa intestinal para el diagnóstico de enfermedad celíaca

BACKGROUND/AIMS: Our aims were to establish the clinical utility of assessing the intraepithelial lymphocyte (IEL) density in intestinal biopsies from a large series of individuals and to determine the best threshold discriminating celiac disease (CD) patients and controls in two populations with different pre-test prevalence. METHODS: We prospectively performed intestinal biopsy and CD-related serology in 349 subjects undergoing upper GI endoscopy. While 116 had symptoms suggestive of a small bowel disorder (high prevalence), 233 individuals were randomly selected from patients referred to endoscopy because upper GIsymptoms (low prevalence). Diagnosis of CD was based on the concordance of classical histological features and a positive CD serology. RESULTS: While 58 patients had a newly diagnosed CD (52 in the high and 6 in the low prevalence groups), 291 subjects did not meet diagnostic criteria of the disorder. Patients had a highly significant greater IEL density than controls (p < 0.00001). Based on the ROC curve, a count of 22.8 IEL/100 epithelial cells had the highest performance for diagnosing CD in the overall population and for subjects in the high pre-test probability subgroup and 22.5% was ,he best cut-off for those diagnosed in the low risk population (area under the curves: 0.979, 0.979 and 0.993, respectively). An abnormal CD serology confirmed the diagnosis of CD in all the four patients with counts below 22.8%. CONCLUSIONS: Our study confirms that an IEL density of 22.8% is an adequate threshold to discriminate CD patients and controls in individuals irrespective of the prevalence of the disorder.

Introducción: El recuento elevado de linfocitos intraepiteliales (LIEs) es un rasgo destacado aunque inespecífico de la enteropatía de la enfermedad celíaca (EC). Un recuento mayor a 40 LIEs/100 células epiteliales ha sido considerado por mucho tiempo esencial para el diagnóstico. Sin embargo, estudios recientes con escaso número de muestras han cuestionado este valor de corte. Objetivos: Determinar el rango normal de LIEs en biopsias intestinales y establecer su capacidad diagnóstica de EC en dos poblaciones con diferente prevalencia. Métodos: Realizamos prospectivamente biopsias de duodeno distal y serología para EC en 349 pacientesconsecutivos a quienes se les realizó una videoendoscopia digestiva alta. El grupo A consistió en 116 pacientes derivados a biopsia intestinal por síntomas sugestivos de malabsorción (considerados de alta prevalencia de EC) y el grupo B consistió en 233 pacientes randomizados entre quienes fueron derivados a endoscopía alta por síntomas gastrointestinales no sugestivos de EC (baja prevalencia de EC). El diagnóstico de EC se basó en criterios histológicos clásicos y serología positiva. Resultados: Cincuenta y ocho pacientes tuvieron EC (52 en el grupo de alto riesgo y 6 en el de baja prevalencia) y 291 individuos no tuvieron criterios de la enfermedad. Los pacientes tuvieron una densidad de LIEs significativamente mayor que los controles (p<0.00001). Basado en las curvas ROC, el conteo de 22.8 LIEs/100 células epiteliales tuvo la mejor sensibilidad y especificidad para el diagnóstico de EC en la población general y entre los sujetos con alta probabilidad y 22.5% fue el mejor valor de corte para la población de bajo riesgo (áreas bajo las curvas: 0.979, 0.979 y 0.993, respectivamente). Todos aquellos pacientes celíacos con recuento de LIEs por debajo de 22% (n=4), tuvieron serología positiva para EC. El clásico valor de 40% tuvo una sensibilidad del 55%. Conclusiones: Nuestro estudio confirma que una...