IgA Function in Relation to the Intestinal Microbiota.

IgA is the dominant immunoglobulin isotype produced in mammals, largely secreted across the intestinal mucosal surface. Although induction of IgA has been a hallmark feature of microbiota colonization following colonization in germ-free animals, until recently appreciation of the function of IgA in host-microbial mutualism has depended mainly on indirect evidence of alterations in microbiota composition or penetration of microbes in the absence of somatic mutations in IgA (or compensatory IgM). Highly parallel sequencing techniques that enable high-resolution analysis of either microbial consortia or IgA sequence diversity are now giving us new perspectives on selective targeting of microbial taxa and the trajectory of IgA diversification according to induction mechanisms, between different individuals and over time. The prospects are to link the range of diversified IgA clonotypes to specific antigenic functions in modulating the microbiota composition, position and metabolism to ensure host mutualism.

Early-onset tufting enteropathy in HAI-2-deficient mice is independent of matriptase-mediated cleavage of EpCAM.

Congenital tufting enteropathy (CTE) is a life-threatening intestinal disorder resulting from loss-of-function mutations in EPCAM and SPINT2. Mice deficient in Spint2, encoding the protease inhibitor HAI-2, develop CTE-like intestinal failure associated with a progressive loss of the EpCAM protein, which is caused by unchecked activity of the serine protease matriptase (ST14). Here, we show that loss of HAI-2 leads to increased proteolytic processing of EpCAM. Elimination of the reported matriptase cleavage site strongly suppressed proteolytic processing of EpCAM in vitro and in vivo. Unexpectedly, expression of cleavage-resistant EpCAM failed to prevent intestinal failure and postnatal lethality in Spint2-deficient mice. In addition, genetic inactivation of intestinal matriptase (St14) counteracted the effect of Spint2 deficiency in mice expressing cleavage-resistant EpCAM, indicating that matriptase does not drive intestinal dysfunction by excessive proteolysis of EpCAM. Interestingly, mice expressing cleavage-resistant EpCAM developed late-onset intestinal defects and exhibited a shortened lifespan even in the presence of HAI-2, suggesting that EpCAM cleavage is indispensable for EpCAM function. Our findings provide new insights into the role of EpCAM and the etiology of the enteropathies driven by Spint2 deficiency.

Diagnosis of Seronegative and Ultrashort Celiac Disease.

In its conventional form, celiac disease (CeD) is characterized by both positive serology and flat villi in the duodenum, and is well known by gastroenterologists and general practitioners. The aim of this review was to shed light on 2 neglected and not yet well-defined celiac phenotypes, that is, seronegative and ultrashort CeD. Seronegative CeD can be suspected in the presence of flat villi, positive HLA-DQ2 and/or HLA-DQ8, and the absence of CeD antibodies. After ruling out other seronegative enteropathies, the diagnosis can be confirmed by both clinical and histologic improvements after 1 year of a gluten-free diet. Ultrashort CeD is characterized by the finding of flat villi in the duodenal bulb in the absence of mucosal damage in the distal duodenum and with serologic positivity. Data on the prevalence, clinical manifestations, histologic lesions, genetic features, and outcome of seronegative and ultrashort CeD are inconclusive due to the few studies available and the small number of patients diagnosed. Some additional diagnostic tools have been developed recently, such as assessing intestinal transglutaminase 2 deposits, flow cytometry technique, microRNA detection, or proteomic analysis, and they seem to be useful in the identification of complex cases. Further cooperative studies are highly desirable to improve the knowledge of these 2 still-obscure variants of CeD.

New entity of adult ultra-short coeliac disease: the first international cohort and case-control study.

BACKGROUND: Ultra-short coeliac disease (USCD) is defined as villous atrophy only present in the duodenal bulb (D1) with concurrent positive coeliac serology. We present the first, multicentre, international study of patients with USCD. METHODS: Patients with USCD were identified from 10 tertiary hospitals (6 from Europe, 2 from Asia, 1 from North America and 1 from Australasia) and compared with age-matched and sex-matched patients with conventional coeliac disease. FINDINGS: Patients with USCD (n=137, median age 27 years, IQR 21-43 years; 73% female) were younger than those with conventional coeliac disease (27 vs 38 years, respectively, p<0.001). Immunoglobulin A-tissue transglutaminase (IgA-tTG) titres at index gastroscopy were lower in patients with USCD versus conventional coeliac disease (1.8×upper limit of normal (ULN) (IQR 1.1-5.9) vs 12.6×ULN (IQR 3.3-18.3), p<0.001).Patients with USCD had the same number of symptoms overall (median 3 (IQR 2-4) vs 3 (IQR 1-4), p=0.875). Patients with USCD experienced less iron deficiency (41.8% vs 22.4%, p=0.006).Both USCD and conventional coeliac disease had the same intraepithelial lymphocytes immunophenotype staining pattern; positive for CD3 and CD8, but not CD4.At follow-up having commenced a gluten-free diet (GFD) (median of 1181 days IQR: 440-2160 days) both USCD and the age-matched and sex-matched controls experienced a similar reduction in IgA-tTG titres (0.5 ULN (IQR 0.2-1.4) vs 0.7 ULN (IQR 0.2-2.6), p=0.312). 95.7% of patients with USCD reported a clinical improvement in their symptoms. INTERPRETATION: Patients with USCD are younger, have a similar symptomatic burden and benefit from a GFD. This study endorses the recommendation of D1 sampling as part of the endoscopic coeliac disease diagnostic workup.

Gluten-related Disorders From Bench to Bedside.

Celiac disease, non-celiac gluten sensitivity, and wheat allergy comprise 3 of the main conditions with wheat- and gluten-containing foods as the symptom trigger. Distinguishing between these entities can be daunting. In this review, we compare and contrast celiac disease, non-celiac gluten sensitivity, and wheat allergy to allow clinicians to determine which diagnosis fits their patient to facilitate high-quality management and longitudinal care.

Biallelic variants of the first Kunitz domain of SPINT2 cause a non-syndromic form of congenital diarrhea and tufting enteropathy.

Biallelic SPINT2 pathogenic variants cause a syndromic form of congenital diarrhea and enteropathy (OMIM 270420). To date, 35 patients have been reported and all presented with additional extra-intestinal features, apart from one case. We report on a 5-year-old girl who presented early in life with diarrhea and was found to have a novel homozygous variant in SPINT2. Pathological studies confirmed tufting enteropathy, and during her 5 years of life, she has not developed any extra-intestinal features. Molecular analysis detected a homozygous variant (NM_021102.4: c.203A>G (p. [Tyr68Cys]) in SPINT2. This is the first missense variant reported in the first Kunitz domain (KD1) of SPINT2 in humans. In vitro functional studies of this variant confirmed the deleterious effect leading to the loss of inhibitory activity of the intestinal serine proteases. This is the first description of SPINT2-related diarrhea in a patient who lived without long-term total parenteral nutrition. This study expands the clinical and molecular characteristics of SPINT2-related conditions.

Genotype and phenotype characterization of primary hypertrophic osteoarthropathy type 2 and chronic enteropathy associated with SLCO2A1: Report of two cases and literature review.

Autosomal recessive type 2 primary hypertrophic osteoarthropathy (PHOAR2) and chronic enteropathy associated with SLCO2A1 (CEAS) are two entities caused by pathogenic variants (PVs) in the SLCO2A1 gene that can coexist or occur independently from one another. We report two cases of PHOAR2 in Mexico with concomitant CEAS and conducted a review of the literature of the reported cases of PHOAR2 and/or CEAS to analyze the relationship between their genotype and phenotype presentation. The patients from our Institution with classical PHOAR2 phenotype and CEAS, harbored SLCO2A1 c.547G > A and c.1768del variants. We reviewed 232 cases, of which 86.6% were of Asian origin, and identified 109 different variants in SLCO2A1. Intron 7, exon 13, and exon 4 were predominantly affected. The two most common PVs were c.940 + 1G > A and c.1807C > T. We found a statistically significant association between SLCO2A1 variants located in intron 7, exons 12, and 13 and the development of CEAS. Missense variants were more frequent in isolated PHOAR2, while a greater proportion of protein-truncating variants (PTVs) were found in CEAS. Further investigation is imperative to elucidate the underlying pathophysiological mechanisms associated with CEAS, thereby facilitating the identification of effective therapeutic interventions.

Maternal, obstetrical, and neonatal outcomes in celiac disease.

OBJECTIVES: Some studies have suggested a link between celiac disease (CD) and adverse maternal, obstetrical, and neonatal outcomes. Using a large database, we evaluated the effect of CD on pregnancy outcomes. METHODS: We conducted a retrospective cohort study using the National Inpatient Sample (NIS) of all deliveries from 2015 to 2019 in the United States. Using ICD-10 codes, we identified pregnant patients who had CD and those who did not. A multivariate logistic regression was used to generate odds ratios (ORs) with 95% confidence intervals (CIs) for maternal, obstetrical, and neonatal outcomes. RESULTS: Of 12,039,222 deliveries between 2015 and 2019, there were 10,555 births in women with CD. Pregnant women with CD were more likely to be white and older compared to those without CD. Pregnant women with CD were significantly more likely to carry a diagnosis of gestational hypertension (OR 1.26; 95% CI 1.04-1.52), preeclampsia (1.28; 1.08-1.53), and severe preeclampsia (1.62; 1.25-2.09). They were less likely to have a full-term uncomplicated delivery (OR 0.11; 95% CI, 0.05-0.20), while being more likely to require device-assisted delivery (1.25; 1.04-1.50) and sustain 3rd or 4th degree vaginal lacerations (1.56; 1.21-2.02). Babies of pregnant women with CD were more likely to be small for gestational age (SGA) (OR 1.29; 95% CI 1.03-1.61). CONCLUSIONS: CD in pregnancy appears to be associated with increased adverse maternal, obstetrical, and neonatal outcomes. Clinicians should discuss these increased risks with CD patients who are planning to conceive.

Prevalence and clinical outcomes of COVID-19 in patients with pre-existing celiac disease: A systematic review and meta-analysis.

There is a scarcity of scientific evidence addressing the outcomes of COVID-19 in celiac disease (CD) patients. This systematic review and meta-analysis aimed to evaluate the correlation between pre-existing CD and COVID-19. A rigorous literature search was conducted using multiple databases. All eligible observational studies were included from around the globe. The random effect model calculated the pooled prevalence and associated 95% confidence intervals (CI). Mantel-Haenszel odds ratios were produced to report the overall effect size using random effect models for severity and mortality outcomes. Funnel plots, Egger regression tests, and Begg-Mazumdar's rank correlation test were used to appraise publication bias. Data from 11 articles consisting of 44,378 CD patients were obtained. Overall pooled random-effects estimate of SARS-CoV-2 infection in CD patients was 4.25% (95% CI, I2  = 98%). Our findings also indicated that pre-existing CD was not associated with an increased risk of hospitalisation with COVID-19 illness (OR = 1.04, 95% CI 0.87-1.24, I2  = 0%) and mortality due to illness (OR = 0.92, 95% CI 0.56-1.5, I2  = 45%) compared with patients without pre-existing CD. No significant publication bias was evident in the meta-analysis. The preliminary data from our analysis suggest that SARS-CoV-2 infection in patients with pre-existing CD is not associated with an increased risk of hospitalisation or mortality. Additional studies are required to overcome the restrictions of the limited data available at present.

Role of peripheral and tissue eosinophils and eosinophil cationic protein in pediatric inflammatory bowel disease.

OBJECTIVES: Inflammatory bowel disease (IBD), eosinophilic gastrointestinal disease (EGID), and functional abdominal pain disorder (FAPD) present with nonspecific gastrointestinal (GI) symptoms clinically and also have some similarities in pathogeneses associated with eosinophils. Therefore, we aimed to evaluate the role of eosinophils in IBD compared to EGID and FAPD by investigating eosinophils in peripheral blood and GI tissue and eosinophil cationic protein (ECP). METHODS: Pediatric patients with chronic GI symptoms who underwent endoscopic biopsies were enrolled. Complete blood cell counts, inflammatory markers, immunoglobulin E (IgE), serum ECP levels, and endoscopic and histopathologic findings were retrospectively reviewed. RESULTS: A total of 387 patients were included: 179 with EGID, 107 with IBDs, and 82 with FAPD. Peripheral absolute eosinophil count (AEC), total IgE, and serum ECP were significantly higher in both IBD and EGID than in FAPD (all p < 0.05). Statistically significant differences were noted among the three groups in tissue eosinophil counts in each segment of GI tract except for the esophagus (p < 0.05). Significant differences were observed in tissue eosinophil counts in the ascending, sigmoid colon, and rectum between EGID and IBD (p < 0.05). Peripheral and tissue eosinophils in the stomach and duodenum revealed positive correlation in both EGID and IBD (both p < 0.001). CONCLUSION: Elevated eosinophil-related markers, as well as increased tissue eosinophilic infiltration in the affected areas of the GI tract in both IBD and EGID compared to FAPD, suggest that eosinophils might play a common important role in the pathogeneses of both diseases.

A case of excisionally remitted indolent NK-cell enteropathy in the oral cavity and a mini-review.

Benign natural killer cell enteropathy (NKCE) was first identified in the gastrointestinal (GI) tract. Notably, instances of NKCE have previously been observed at various sites other than the GI tract, including the gallbladder, lymph nodes, esophagus, and female genital tract. Typical NKCE manifests as an NK-cell immunohistological phenotype, with or without TCR rearrangement, and is characterized by the absence of Epstein-Barr virus (EBV) infection and protracted clinical progression. The misdiagnosis of NKT-cell lymphoma has resulted in some patients receiving chemotherapy, while in other instances, the patients' conditions resolved without treatment and showed no evidence of disease recurrence or progression during follow-up examinations. In this paper, we describe a unique case of EBV-negative NKCE occurring in the oral cavity, the first time such a case has been documented. The tumor completely resolved after an excisional biopsy, and subsequent follow-up did not reveal any signs of disease recurrence.

Protein-losing enteropathy as a new phenotype in atypical hemolytic uremic syndrome caused by CD46 gene mutation.

BACKGROUND: Atypical hemolytic uremic syndrome (aHUS) is a life-threatening thrombotic microangiopathy. Genetic defects in the alternative complement (AP) pathway have been identified in 60-70% of individuals. Eculizumab is recommended as a first-line therapy. METHODS: We collected the clinical data of a pediatric patient with aHUS accompanied by protein-losing enteropathy (PLE). Genetic testing was performed. Related literature on aHUS combined with PLE was reviewed. RESULTS: A 15-year-old Chinese girl was diagnosed with aHUS at 3.7 years of age and experienced five episodes; her symptoms completely resolved with plasma treatment. Severe gastrointestinal symptoms and hypoalbuminemia presented after the first episode, and PLE was diagnosed. A novel homozygous CD46 variant was identified, and FACS revealed significantly decreased CD46 expression. She presented at a recent relapse with persistent GI symptoms and headache and progressed to chronic kidney failure; peritoneal dialysis was initiated. Eculizumab was given 8 months after the last recurrence. Surprisingly, PLE was cured. Afterward, dialysis was discontinued, and eGFR recovered to 44.8 ml/min/1.73 m2. A review of the literature indicated that PLE with thrombosis was caused by CD55 variants via hyperactivation of the AP system. We report an aHUS patient with PLE caused by CD46 variants. Symptoms of both PLE and aHUS were significantly alleviated in our patient and patients with CD55 variants treated with eculizumab, indicating that PLE was a new symptom of aHUS in our patient with a CD46 variant. CONCLUSIONS: Our case expands the phenotype of aHUS caused by a CD46 mutation and provides evidence of the efficacy of eculizumab after a long phase of chronic kidney failure.

A dual role of lysophosphatidic acid type 2 receptor (LPAR2) in nonsteroidal anti-inflammatory drug-induced mouse enteropathy.

Lysophosphatidic acid (LPA) is a bioactive phospholipid mediator that has been found to ameliorate nonsteroidal anti-inflammatory drug (NSAID)-induced gastric injury by acting on lysophosphatidic acid type 2 receptor (LPAR2). In this study, we investigated whether LPAR2 signaling was implicated in the development of NSAID-induced small intestinal injury (enteropathy), another major complication of NSAID use. Wild-type (WT) and Lpar2 deficient (Lpar2-/-) mice were treated with a single, large dose (20 or 30 mg/kg, i.g.) of indomethacin (IND). The mice were euthanized at 6 or 24 h after IND treatment. We showed that IND-induced mucosal enteropathy and neutrophil recruitment occurred much earlier (at 6 h after IND treatment) in Lpar2-/- mice compared to WT mice, but the tissue levels of inflammatory mediators (IL-1ß, TNF-α, inducible COX-2, CAMP) remained at much lower levels. Administration of a selective LPAR2 agonist DBIBB (1, 10 mg/kg, i.g., twice at 24 h and 30 min before IND treatment) dose-dependently reduced mucosal injury and neutrophil activation in enteropathy, but it also enhanced IND-induced elevation of several proinflammatory chemokines and cytokines. By assessing caspase-3 activation, we found significantly increased intestinal apoptosis in IND-treated Lpar2-/- mice, but it was attenuated after DBIBB administration, especially in non-obese diabetic/severe combined immunodeficiency (NOD/SCID) mice. Finally, we showed that IND treatment reduced the plasma activity and expression of autotaxin (ATX), the main LPA-producing enzyme, and also reduced the intestinal expression of Lpar2 mRNA, which preceded the development of mucosal damage. We conclude that LPAR2 has a dual role in NSAID enteropathy, as it contributes to the maintenance of mucosal integrity after NSAID exposure, but also orchestrates the inflammatory responses associated with ulceration. Our study suggests that IND-induced inhibition of the ATX-LPAR2 axis is an early event in the pathogenesis of enteropathy.

A Dedicated Celiac Disease Program Improves Celiac Quality Care Metrics and Short-Term Outcomes in Real Life.

BACKGROUND AND AIMS: Dedicated multidisciplinary programs in gastroenterology are emerging with the goal to improve care. There is little information about the effects of a celiac disease program on disease-related quality care metrics and outcomes. We aimed to compare quality care metrics, symptom resolution, and serological response among patients diagnosed and treated in a celiac disease program with a standard of care cohort. METHODS: We performed a retrospective cohort study with adult celiac disease patients. We divided patients into two groups: celiac disease patients treated in our program and those treated by gastroenterologists not affiliated with the program (standard of care). We abstracted data from electronical medical records and compared frequency at which guideline-driven quality care metrics were obtained, assessed symptom resolution, and serological response based on IgA anti-tissue transglutaminase levels. RESULTS: We included 340 patients, 120 in the celiac disease program (89 women) and 220 (166 women) in the standard of care. Frequency of quality care metrics implementation in program patients was significantly greater for all variables (p < 0.0005). Diarrhea resolved in 38/46 (82.6%) in the CD program and 63/98 (64.2%) in the standard of care after starting a gluten-free diet (p = .025); bloating also resolved significantly more often in the former (26/34) than the latter (31/58; p = 0.03). Otherwise, there were no significant differences in resolution of clinical symptoms or serological response. CONCLUSION: A celiac disease program improves celiac-related quality care metrics and may improve outcomes such as diarrhea resolution compared to standard of care.

Predictors of Subsequent Celiac Disease Seropositivity in Patients Diagnosed with Duodenal Villus Atrophy on Upper Endoscopy.

BACKGROUND: The diagnosis of celiac disease (CD) is based on positive IgA autoantibodies to tissue transglutaminase (TTG IgA) and confirmatory histopathology demonstrating duodenal villus atrophy (VA). Diagnostic challenges can occur when VA is found on duodenal biopsies in patients without prior CD serologies. AIMS: To characterize the predictors of CD seropositivity in patients with VA on biopsy without prior CD serologies. METHODS: We performed a retrospective cohort study of patients found to have duodenal VA on histopathology from 2010 to 2020 who did not have prior CD serologies measured and who had them checked after their biopsy. Patients with known or suspected CD prior to their duodenal biopsy were excluded. RESULTS: Of 162 patients with VA and no prior CD serologies, 50 (31%) subsequently had an elevated TTG IgA consistent with CD. Patients with an elevated TTG IgA were more likely to be non-Hispanic (76% vs. 42%; p < 0.001), white (74% vs. 62%; p = 0.025), and younger (ages 18-39, 26% vs. 12%; p = 0.002) compared to those with a negative TTG IgA. By contrast, these patients were less likely to present in middle adulthood (ages 40-59, 6% vs. 29%; p =  0.002). The most common identified etiologies of seronegative VA were Crohn's disease (13%), seronegative CD (8.9%), H. pylori infection (6.3%), tropical sprue (5.4%), and olmesartan-related enteropathy (3.6%). CONCLUSION: Age and ethnicity may be helpful when stratifying the likelihood of CD in the absence of supporting serologies. A majority of patients (69%) diagnosed with VA without prior CD serologies have negative serologies, consistent with seronegative CD or the spectrum of non-celiac enteropathies for which further evaluation is needed.

Hereditary Multiple Intestinal Atresia With a Novel TTC7A Pathogenic Variant: Gastrointestinal Manifestations in Two Cases.

Hereditary multiple intestinal atresia (HMIA) with TTC7A mutation is caused by homozygous or compound heterozygous TTC7A gene mutation. It is characterized by multiple small and large intestinal atresias and/or stenoses. TTC7A mutation is described in some patients with inflammatory bowel disease and mild-severe forms of severe combined immunodeficiency without intestinal atresia or stenosis. We present 2 cases of intestinal atresia and documented TTC7A mutation with a novel variant. Both cases had different clinical and pathological manifestations. The first case is a male infant born at 35 weeks of gestation with failure to pass meconium. Intestinal biopsy reveals apoptotic enteropathy with villous atrophy and increased mucosal eosinophils. The second case is referred at birth for antenatally detected umbilical hernia, polyhydramnios and possible upper intestinal obstruction. The resected specimen reveals ileal atresia with partial villous atrophy, decreased number of lamina propria inflammatory cells and absence of plasma cells. In conclusion, these cases reflect an emerging TTC7A pathogenic variant with different histological manifestations and leads to characterization as immune dysregulation disorder. There is a need to differentiate TTC7A mutation associated ones from cases labeled as very early onset IBD and rule out other hereditary immunodeficiencies.

Patients with Celiac Disease Have High Prevalence of Fatty Liver and Metabolic Syndrome.

OBJECTIVE: In recent years, patients with celiac disease (CeD) have been reported to have a high prevalence of fatty liver and metabolic syndrome. We conducted a systematic review and meta-analysis to assess the prevalence of fatty liver and metabolic syndrome in patients with CeD and effect of gluten-free diet in them. METHODS: The PubMed, Embase and the Cochrane Library databases were searched for original studies upto November 18, 2022. We included full-text articles published in the English language after 1990 that used well-defined criteria for CeD, fatty liver and metabolic syndrome. A random effects model was used to calculate pooled prevalence. RESULTS: Of 350 studies identified, 11 studies (n = 2578) were included in the analysis. On analysis of both cross-sectional and longitudinal studies, pooled prevalence of fatty liver and metabolic syndrome in treatment-naïve patients with CeD were 18.2% (95% CI 8.3-30.8%, n = 1237) and 4.3% (95% CI 2.4-6.7, n = 1239) and in those on GFD of varying duration was 28.2% (95% CI 20.7-36.4%, n = 1368) and 21.3% (95% CI 11.7-32.9%, n = 2193), respectively. There was no difference in the prevalence of fatty liver and metabolic syndrome between low- or high-income group countries. CONCLUSIONS: Patients with CeD have a high prevalence of fatty liver and metabolic syndrome which increases further with the initiation of GFD. Patients with CeD should thus be screened and monitored for development of fatty liver and metabolic syndrome. They should be counselled appropriately regarding their diet and inclusion of physical activity in their lifestyle.

Duodenal and colonic mucosal S100A8/A9 (calprotectin) expression is increased and correlates with the severity of select histologic lesions in dogs with chronic inflammatory enteropathy.

BACKGROUND: Calprotectin, a damage-associated molecular pattern protein of the S100/calgranulin family, is a potential marker of gastrointestinal inflammation in dogs and mainly originates from activated macrophages and granulocytes. Increased calprotectin concentrations are reported in feces and serum samples from dogs with chronic inflammatory enteropathy (CIE), but mucosal calprotectin expression has not been extensively investigated in canine CIE. Thus, we aimed to evaluate gastrointestinal mucosal concentrations of calprotectin in 62 dogs (44 dogs with CIE compared to 18 healthy Beagles) using a particle-enhanced turbidimetric immunoassay method. Additionally, we assessed the relationship of gastric, duodenal, jejunal, ileal, and colonic mucosal calprotectin levels with the clinical disease severity (canine clinical inflammatory bowel disease activity index, CIBDAI), histopathologic findings, clinical outcome, and serum albumin concentrations to further evaluate the potential of calprotectin as a biomarker for CIE. RESULTS: Mucosal calprotectin concentrations in dogs with CIE were significantly higher in the duodenum (median: 276.2 µg/g) and colon (median: 298.2 µg/g) compared to healthy controls (median: 94.3 µg/g, P = 0.0039; and median: 112.0 µg/g, P = 0.0061). Similar numerical differences in the ileum and cecum were not statistically significant, and mucosal calprotectin concentrations correlated significantly among the different gastrointestinal segments. Histologic lesion severity was linked to mucosal calprotectin concentrations for inflammatory and structural histology criteria in the duodenum and colon (all P < 0.05). Higher mucosal calprotectin levels in the duodenum and across all segments correlated with lower serum albumin concentrations (both P < 0.05); duodenal mucosal calprotectin concentrations were more than sixfold higher in hypoalbuminemic dogs (median: 1441 µg/g, n = 4) than normoalbuminemic dogs (median: 227 µg/g, n = 40). There was no significant association of mucosal calprotectin levels with CIBDAI scores or individual clinical outcomes. CONCLUSIONS: These results show that duodenal and colonic mucosal calprotectin concentrations are increased in dogs with CIE, providing further supporting evidence for the diagnostic potential of fecal calprotectin (presumably reflecting mucosal) concentrations and in dogs with CIE. Further longitudinal research is needed to assess changes in mucosal calprotectin concentrations with clinical response to treatment vs. mucosal disease remission and to determine the clinical utility of fecal calprotectin concentrations to diagnose and monitor dogs with CIE in clinical practice.

Recurrent cellulitis and bacteremia in a patient with Noonan syndrome: A case report.

A 28-year old Japanese man with Noonan syndrome (NS) presented to our emergency department with painful erythema of the trunk and lower extremities since the previous day. He had been diagnosed with protein-losing enteropathy (PLE) with intestinal lymphangiectasia at age 25 years, and undergone lymphaticovenular anastomosis (LVA) twice. Three episodes of cellulitis of both lower extremities had occurred in the past 2 years. Extensive cellulitis with sepsis was diagnosed and piperacillin/tazobactam was started, which was de-escalated to ceftriaxone. He was discharged after 13 days of antibiotic therapy. After discharge, low-dose trimethoprim-sulfamethoxazole (SMZ-TMP) was started as the primary prophylaxis, but three episodes of cellulitis occurred in the next year and were treated with other antibiotics. NS, an autosomal dominant disease known as a RASopathy, is caused by germline mutations in RAS-MAPK pathway genes. Lymphedema resulting from lymphatic abnormalities is a concomitant manifestation in 20 % of patients with NS, and can be a risk factor for cellulitis. Hypoalbuminemia and hypoglobulinemia associated with PLE facilitate infections such as cellulitis. As a treatment for lymphedema in the extremities, LVA has shown objective and subjective improvements in most patients, and some studies have also reported its efficacy for lymphedema in patients with NS. Targeted molecular therapy with mitogen-activated protein kinase enzyme (MEK) inhibitor is used in treatment of cancers with activation of the RAS/MAPK pathway. MEK inhibitors have recently been tried in patients with RASopathies and severe lymphatic disorders, and can lead to rapid resolution of symptoms.

Artificial intelligence-based quantification of lymphocytes in feline small intestinal biopsies.

Feline chronic enteropathy is a poorly defined condition of older cats that encompasses chronic enteritis to low-grade intestinal lymphoma. The histological evaluation of lymphocyte numbers and distribution in small intestinal biopsies is crucial for classification and grading. However, conventional histological methods for lymphocyte quantification have low interobserver agreement, resulting in low diagnostic reliability. This study aimed to develop and validate an artificial intelligence (AI) model to detect intraepithelial and lamina propria lymphocytes in hematoxylin and eosin-stained small intestinal biopsies from cats. The median sensitivity, positive predictive value, and F1 score of the AI model compared with the majority opinion of 11 veterinary anatomic pathologists, were 100% (interquartile range [IQR] 67%-100%), 57% (IQR 38%-83%), and 67% (IQR 43%-80%) for intraepithelial lymphocytes, and 89% (IQR 71%-100%), 67% (IQR 50%-82%), and 70% (IQR 43%-80%) for lamina propria lymphocytes, respectively. Errors included false negatives in whole-slide images with faded stain and false positives in misidentifying enterocyte nuclei. Semiquantitative grading at the whole-slide level showed low interobserver agreement among pathologists, underscoring the need for a reproducible quantitative approach. While semiquantitative grade and AI-derived lymphocyte counts correlated positively, the AI-derived lymphocyte counts overlapped between different grades. Our AI model, when supervised by a pathologist, offers a reproducible, objective, and quantitative assessment of feline intestinal lymphocytes at the whole-slide level, and has the potential to enhance diagnostic accuracy and consistency for feline chronic enteropathy.