Dietary Factors May Delay Tolerance Acquisition in Food Protein-Induced Allergic Proctocolitis.

BACKGROUND: Dietary and environmental factors may influence tolerance acquisition in food protein-induced allergic proctocolitis (FPIAP). This retrospective observational study explored the role of maternal diet during pregnancy and breastfeeding in tolerance acquisition in infantile FPIAP. METHODS: Breastfed infants with FPIAP from six diverse regions in Greece were divided into two groups, based on development of tolerance to the trigger food: Group A (n = 43), before, and Group B (n = 53), after, the 6th month of age. Maternal diet during pregnancy and breastfeeding was elicited using the Mediterranean Diet Score Questionnaire and the Mediterranean Oriented Culture Specific Semi-Quantitative Food Frequency Questionnaire. RESULTS: Mean age at diagnosis of FPIAP (1.5 months) and weaning (5.5 months) were the same in both groups. The main trigger was cow's milk. Group A received infant milk formula earlier than Group B. Group B had a higher incidence of asthma/wheeze, siblings with milk allergy, maternal smoking and rural residence. On multivariate analysis, earlier resolution of FPIAP was associated with higher maternal education and with salt intake and consumption of goat/sheep cheese during pregnancy and olive oil during breastfeeding. Consumption of multivitamins during pregnancy and meat, winter fruits, green vegetables, butter, salt, "ready-to-eat" meals and pastries during breastfeeding were correlated with longer duration of symptoms. CONCLUSIONS: Mothers of children with FPIAP to cow's milk protein can be advised to eat more yogurt, cheese and olive oil during subsequent pregnancies, and avoid multivitamins, grilled food, "ready-to-eat" meals, pastries, meat and alcohol during breastfeeding, to reduce the duration of FPIAP presenting in future infants.

Assessment of intracellular zinc levels in infants with food protein–induced allergic proctocolitis

Background: Food protein–induced allergic proctocolitis (FPIAP) is characterized by bloody stools in well-appearing infants. Zinc is a micronutrient that plays a crucial role in immune modulation and is essential for cellular function during immune response. Although there are studies on the assessment of intracellular zinc levels in allergic diseases, no data is available on erythrocyte zinc levels of patients with FPIAP. Objective: This study aimed to assess the erythrocyte zinc levels of children with allergic proctocolitis and compare zinc levels with clinical and demographic characteristics. Methods: This was a case–control study that prospectively compared 50 patients with FPIAP and 50 healthy children without malnutrition. The erythrocyte zinc levels of children were determined using atomic absorption spectrophotometry. Results: Fifty patients with FPIAP, including 28 (51%) girls, with median age of 7.1 ± 2.9 (3–14) months and 50 healthy children, including 26 (53.1%) girls, with median age of 7.7 ± 2.8 (3–13) months were included in the study. Seventy percent (n = 35) of the patients with FPIAP started to have symptoms while they were exclusively breastfeeding. Offending allergen foods were cow’s milk (78%), egg (40%), sesame (10%), hazelnut (8%), almond (6%), beef (6%), and peanuts (6%, n = 3). Intracellular (erythrocyte) zinc levels in patients with FPIAP were lower than in the healthy control group (495.5 ± 134 µg/dL, 567.3 ± 154.4 µg/dL, respectively, P = 0.01). Patients with FPIAP aged younger than 6 months had lower intracellular zinc levels compared with those aged above 6 months (457 ± 137 µg/dL; 548 ± 112 µg/dL, respectively, P = 0.01). There was no relationship between zinc levels and time of symptom onset, presence of concomitant disease, being allergic to multiple foods, and family history of atopy (P > 0.05). Conclusions: FPIAP is a food allergy with limited information on its pathogenesis (AU)

[Non-IgE-mediated food allergy]. / Alergia alimentaria no mediada por IgE.

Food allergy is an immune response to proteins in food. It usually affects 8% of children and 2% of adults in Western countries. Non-IgE-mediated food allergy mainly affects the gastrointestinal tract. Gastrointestinal food allergies are classified, by their underlying pathogenesis, as: IgE-mediated, non-IgE-mediated, or mixed. The symptoms of patients with food protein-induced allergic proctocolitis originate from local inflammation of the distal colon, which causes hematochezia in neonates. It can affect the entire gastrointestinal tract and cause symptoms of intractable emesis, with subsequent metabolic disorders and hypovolemic shock. Food protein-induced enterocolitis syndrome is a non-IgE-mediated allergy that usually appears in childhood, with prolonged repetitive vomiting, starting 1 to 4 hours after ingestion of food. The manifestation in adults is usually triggered by the consumption of shellfish. Atopic diseases affect 40-60% of patients with food protein- induced enterocolitis syndrome, including 40-50% of those with food protein-induced enteropathy and proctocolitis. Probiotics (Lactobacillus GG) can alleviate the symptoms of allergic proctocolitis induced by food proteins, by altering the composition of the intestinal microbiota. Fecal microbiota transplantation (FMT) can change intestinal microecology efficiently compared to food or probiotics.

La alergia alimentaria es una respuesta inmunitaria a las proteínas de los alimentos. Suele afectar al 8% de los niños y al 2% de los adultos en países occidentales. La alergia alimentaria no mediada por IgE afecta, principalmente, el aparato gastrointestinal. Las alergias alimentarias gastrointestinales se clasifican, por su patogenia subyacente, en: mediadas por IgE, no mediadas por IgE, o mixtas. Los síntomas de pacientes con proctocolitis alérgica inducida por proteínas alimentarias se originan por la inflamación local del colon distal, que causa hematoquecia en neonatos. Puede afectar todo el conducto gastrointestinal y provocar síntomas de emesis intratable, con subsiguientes trastornos metabólicos y choque hipovolémico. El síndrome de enterocolitis inducida por proteínas alimentarias es una alergia no mediada por IgE que suele aparecer en la infancia, con vómito prolongado repetitivo, que inicia entre 1 a 4 horas después de la ingestión de alimentos. La manifestación en adultos suele desencadenarse por el consumo de mariscos. Las enfermedades atópicas afectan del 40-60% de los pacientes con síndrome de enterocolitis inducida por proteínas alimentarias, incluso al 40-50% de quienes padecen enteropatía y proctocolitis inducidas por proteínas alimentarias. Los probióticos (Lactobacillus GG) pueden aliviar los síntomas de proctocolitis alérgica inducida por proteínas alimentarias, al alterar la composición de la microbiota intestinal. El trasplante de microbiota fecal (TMF) puede cambiar la microecología intestinal de manera eficiente comparada con los alimentos o probióticos.

A different starting line for allergic march: food protein-induced allergic proctocolitis

Objective: The aim of this study is to investigate the long-term prognosis of food protein--induced allergic proctocolitis (FPIAP) patients, the risk of developing both allergic and gastrointestinal diseases, and to evaluate whether it leads to allergic march. Methods: A total of 149 children who were diagnosed with FPIAP and developed tolerance at least 5 years prior to the study and 41 children (with no history of food allergy) as a control group were enrolled. Both groups were re-evaluated for allergic diseases as well as gastrointestinal disorders. Results: The mean age of diagnosis for the FPIAP group was 4.2 ± 3.0 months, while the mean age of tolerance was 13.9 ± 7.7 months. The mean age of both FPIAP and control groups at the last visit was 101.6 ± 24.4 and 96.3 ± 24.1 months, respectively (P = 0.213). At the final evaluation of both groups, the comorbid allergic disease was significantly higher in the FPIAP group (P < 0.001). There was no significant difference between the two groups in terms of functional gastrointestinal disorders (FGIDs), eosinophilic gastrointestinal diseases, and inflammatory bowel disease (P = 0.198, 0.579, and 0.579, respectively). In the FPIAP group, the allergic disease was significantly higher at the final visit in patients with comorbid allergic disease at diagnosis (P < 0.001). In the FPIAP group, FGID was significantly higher in the group that developed allergic diseases in the future, compared to the group that did not develop allergic diseases in the future (P = 0.034). The proportion of both FGID and allergic diseases was significantly higher in subjects that developed tolerance at >18 months, compared to subjects that developed tolerance at >18 months (P < 0.001 and <0.001, respectively). Conclusions: Patients with FPIAP may develop allergic diseases as well as FGID in the long term (AU)

INDUCED PROCTOCOLITIS - ORAL FOOD CHALLENGE SHOULD BE DONE TO CONFIRM THE DIAGNOSIS OF COW'S MILK ALLERGY IN NEONATES?

BACKGROUND: Suspicion of food protein-induced proctocolitis based on empirical understanding of rectal bleeding can lead to misdiagnosis. OBJECTIVE: to verify clinical and evaluative characteristics of patients who presented neonatal rectal bleeding and were on a restricted cow's milk diet. METHODS: A cross-sectional retrospective study included patients followed up in a tertiary care center, who presented rectal bleeding in the neonatal period. The analyzed data included gender, gestational age, type of delivery, use of antibiotics during the last trimester of pregnancy, use of parenteral nutrition before the first manifestation, use of mechanical ventilation, initial clinical manifestations associated with rectal bleeding, diet before the first manifestation, period of elimination diet, oral food challenge (OFC) results and symptoms presented in cases of positive OFC. Fisher's exact test and Mann-Whitney test were used to analyze the data. The level of significance was set to 5%. RESULTS: Forty-two patients were selected: 30 preterm infants, 34 cesarean deliveries, 10 exclusively breastfed patients before rectal bleeding. Median age at OFC was 6.3 months old. Median of length of the elimination period before OFC was 5.9 months. OFC was negative in 33/42 (79%) patients and positive in 9/42 (21%). There was no association between OFC results and the evaluated data. The main symptom observed in patients with positive OFC was blood in stools. CONCLUSION: OFC was negative in most cases of suspected cow's milk allergy due to rectal bleeding in neonates, most of them with a history of prematurity.

Longitudinal disease-associated gut microbiome differences in infants with food protein-induced allergic proctocolitis.

BACKGROUND: Complex interactions between the gut microbiome and immune cells in infancy are thought to be part of the pathogenesis for the marked rise in pediatric allergic diseases, particularly food allergies. Food protein-induced allergic proctocolitis (FPIAP) is commonly the earliest recognized non-immunoglobulin E (IgE)-mediated food allergy in infancy and is associated with atopic dermatitis and subsequent IgE-mediated food allergy later in childhood. Yet, a large prospective longitudinal study of the microbiome of infants with FPIAP, including samples prior to symptom onset, has not been done. RESULTS: Here, we analyzed 954 longitudinal samples from 160 infants in a nested case-control study (81 who developed FPIAP and 79 matched controls) from 1 week to 1 year of age by 16S rRNA ribosomal gene sequencing as part of the Gastrointestinal Microbiome and Allergic Proctocolitis (GMAP) study. We found key differences in the microbiome of infants with FPIAP, most strongly a higher abundance of a genus of Enterobacteriaceae and a lower abundance of a family of Clostridiales during the symptomatic period. We saw some of these significant taxonomic differences even prior to symptom onset. There were no consistent longitudinal differences in richness or stability diversity metrics between infants with FPIAP and healthy controls. CONCLUSIONS: This study is the first to identify differences in the infant gut microbiome in children who develop FPIAP, some even before they develop symptoms, and provides a foundation for more mechanistic investigation into the pathogenesis of FPIAP and subsequent food allergic diseases in childhood. Video abstract.

The Low Maternal Consumption of Homemade Fermented Foods in Pregnancy Is an Additional Risk Factor for Food Protein-Induced Allergic Proctocolitis: A Case-Control Study.

INTRODUCTION: Food protein-induced allergic proctocolitis (FPIAP) is the most common non-IgE-mediated food allergy and it varies between 4% and 8% in infants. The aim of the study was to evaluate the potential association between FPIAP in infants and maternal daily consumption of homemade fermented foods (FFs) during pregnancy. METHODS: Two hundred and seven infants were included in this case-control study, 106 with physician-diagnosed FPIAP (FPIAP group) and 101 age- and gender-matched healthy infants (control group), together with their mothers. The frequency and diversity of the 8 most consumed homemade FFs in traditional Turkish cuisine and daily maternal consumption of these during pregnancy were evaluated retrospectively using a structured questionnaire. RESULTS: Rates of vaginal delivery, maternal smoking during pregnancy, educational status, and monthly household income were higher in the FPIAP group than the control group (p = 0.046, p = 0.014, p < 0.001, and p = 0.009, respectively). The 3 most common daily-consumed FFs during pregnancy were, in order, yogurt, cheese, and tarhana. The diversity of daily-consumed FFs during pregnancy (p = 0.004) and the consumption of the 3 most common FFs (p = 0.011) were lower in the FPIAP group than in the control group. Maternal smoking during pregnancy (odds ratio [OR]: 2.97, 95% confidence interval [CI]: 1.19-7.41, p = 0.019) and a higher maternal educational status (OR: 3.34, 95% CI: 1.63-6.84, p = 0.001) increased the risk of FPIAP at multivariate logistic regression, while the diversity of maternal FF consumption was protective against FPIAP (OR: 0.75, 95% CI: 0.58-0.96, p = 0.025). CONCLUSION: Daily maternal consumption of yogurt, cheese, and tarhana during pregnancy was less common in FPIAP. The diversity of traditional Turkish homemade FFs may reduce the risk of FPIAP, whereas maternal smoking and a higher maternal educational status were associated with an increased risk of FPIAP.

Diversion proctocolitis and the problem of the forgotten rectum in inflammatory bowel diseases: A systematic review.

BACKGROUND AND AIMS: Diversion proctocolitis (DP) is a non-specific mucosal inflammation arising in the defunctionalized colon and/or rectum following faecal diversion (colostomy, ileostomy). Differential diagnosis of DP from the underlying disease in patients with inflammatory bowel diseases (IBD) is often unclear. As a result, it might be difficult to undertake any specific treatment. We aimed to systematically review the literature evidence on DP in IBD patients. METHODS: For this qualitative systematic review, we searched PubMed, EMBASE and Scopus to identify all studies published until July 2021 including IBD patients affected by DP. RESULTS: Overall, 37 papers published between 1982 and 2021 were included. A total of 1.211 IBD patients were included: 613 UC (50.6%), 524 CD (43.3%), 66 IBD-unclassified (IBD-U) (5.4%), 8 unspecified patients (0.7%). Most patients with DP are asymptomatic, although inflammation is detectable in almost all patients with a rectal stump. Reduced short-chain fatty acids and an altered microbiome, may trigger mucosal inflammation and have been proposed as causing factors. An increased risk of developing cancer on DP has been reported in patients with a history of previous dysplasia/cancer. CONCLUSIONS: The etiopathogenesis of DP is still unknown. The efficacy of mesalamine, corticosteroids or short-chain fatty acids has not been proven by randomized trials yet. Since the incidence of cancer of the rectal stump can reach 4.5 per 1.000 diverted patients-year, IBD patients undergoing subtotal colectomy with end-ileostomy should undergo close endoscopic surveillance, being eventually counseled for surgery with or without the restoration of the intestinal continuity.

Serological Biomarkers and Diversion Colitis: Changes after Stimulation with Probiotics.

Diversion colitis is a non-specific inflammation of a defunctionalised segment of the colon after a temporary stoma has been performed. This inflammation is associated with an alteration of certain inflammatory serum markers. The aims of this study were, firstly, to evaluate the modification of inflammatory biomarkers after stimulation with probiotics prior to closure of the protective ileostomy. Secondly, to identify if a relationship could be established between the severity of diversion colitis and the alteration of inflammatory biomarkers in the blood. A prospective, randomized, double-blind, controlled study was conducted. Patients who underwent surgery for colorectal carcinoma with protective ileostomy between January 2017 and December 2018 were included, pending reconstructive surgery and with diversion colitis as diagnosis. The sample was randomly divided into a group stimulated with probiotics (SG) (n = 34) and a control group (CG) (n = 35). Histological and endoscopic changes were evaluated after stimulation, after restorative surgery and during the short-term follow-up after surgery, including the correlation with pro-inflammatory biomarkers in blood. As main findings, a significant decrease in C-reactive protein (CRP), Neutrophil/lymphocyte ratio (NLR ratio), and monocyte/lymphocyte ratio (LMR ratio) was observed in the SG versus the CG with a p < 0.001. A significant increase in transferrin values and in the platelet/lymphocyte ratio (PLR) was observed in the SG versus CG after stimulation with probiotics with a p < 0.001. A normalisation of CRP and transferrin levels was observed in the third month of follow-up after closure ileostomy, and NLR, LMR and PLR ratios were equal in both groups. Decreased modified Glasgow prognostic score was found in SG compared to CG after probiotic stimulation (p < 0.001). The endoscopic and histological severity of diversion colitis is associated with a greater alteration of blood inflammatory biomarkers. The stimulation with probiotics prior to reconstructive surgery promotes an early normalization of these parameters.

2021 European Guideline on the management of proctitis, proctocolitis and enteritis caused by sexually transmissible pathogens.

This guideline intents to offer guidance on the diagnosis and management of patients with gastrointestinal symptoms and a suspected sexually transmitted cause. Proctitis is defined as an inflammatory syndrome of the anal canal and/or the rectum. Infectious proctitis can be sexually transmitted via genital-anal mucosal contact, but some also via digital contact and toys. Neisseria gonorrhoeae, Chlamydia trachomatis (including lymphogranuloma venereum), Treponema pallidum and herpes simplex virus are the most common sexually transmitted anorectal pathogens. Shigellosis can be transferred via oral-anal contact and may lead to proctocolitis or enteritis. Although most studies on these infections have concentrated on men who have sex with men (MSM), women having anal intercourse may also be at risk. A presumptive clinical diagnosis of proctitis can be made when there are symptoms and signs, and a definitive diagnosis when the results of laboratory tests are available. The symptoms of proctitis include anorectal itching, pain, tenesmus, bleeding, constipation and discharge in and around the anal canal. The majority of rectal chlamydia and gonococcal infections are asymptomatic and can only be detected by laboratory tests. Therefore, especially when there is a history of receptive anal contact, exclusion of anorectal infections is generally indicated as part of standard screening for sexually transmitted infections (STIs). Condom use does not guarantee protection from STIs, which are often spread without penile penetration. New in this updated guideline is: (i) lymphogranuloma venereum proctitis is increasingly found in HIV-negative MSM, (ii) anorectal Mycoplasma genitalium infection should be considered in patients with symptomatic proctitis after exclusion of other common causations such N. gonorrhoeae, C. trachomatis, syphilis and herpes, (iii) intestinal spirochetosis incidentally found in colonic biopsies should not be confused with syphilis, and (iv) traumatic causes of proctitis should be considered in sexually active patients.

Fatal Outcome Consequent to an Endoscopic Full Thickness Resection of a Colonic Lateral Spreading Tumor: A Case Report.

BACKGROUND Endoscopic full-thickness resection represents an innovative procedure, used in selected patients that allows lesions en-bloc resection with an integral wall specimen available for histopathological definition. Bleeding and perforation are known to be the most frequent procedure-related adverse events. We report a case of entero-colonic fistula as complication of an endoscopic full-thickness resection. CASE REPORT A 77-year-old male, with a personal history of right-hemicolectomy for a colonic adenocarcinoma presented to our department for a routine colonoscopy that showed the presence of a 25 mm lateral spreading tumor localized at about 50 cm from the anal margin. A full-thickness resection of the lateral spreading tumor using the over-the-scope clip device was performed. After 4 weeks, because of abdominal pain, weight loss, diarrhea, and signs of malnutrition, the patient underwent a new colonoscopy showing hyperemic mucosa with ulcerations in all colonic segments and, at the site of the previous endoscopic full-thickness resection, an orifice of an entero-colonic fistula. The histological definition was suggestive for ulcerative proctocolitis and confirmed the presence of small bowel mucosa at fistula orifice. An intussusception at the level of fistula with consequent intestinal obstruction caused a worsening of clinical conditions and finally the patient death for a septic peritonitis. CONCLUSIONS Full thickness resection represents an innovative tool for en-bloc resection of gastrointestinal tumoral lesion, but procedural complications and limitations must be considered before performing this procedure.

Risk Factors Influencing Tolerance and Clinical Features of Food Protein-induced Allergic Proctocolitis.

OBJECTIVE: Continued progress in our understanding of the food protein-induced allergic proctocolitis (FPIAP) will provide the development of diagnostic tests and treatments. We aimed to identify precisely the clinical features and natural course of the disease in a large group of patients. Also, we investigated the predicting risk factors for persistent course since influencing parameters has not yet been established. METHODS: Infants who were admitted with rectal bleeding and had a diagnosis of food protein-induced allergic proctocolitis in 5 different allergy or gastroenterology outpatient clinics were enrolled. Clinical features, laboratory tests, and prognosis were evaluated. Risk factors for persistent course were determined by logistic regression analyses. RESULTS: Among the 257 infants, 50.2% (n = 129) were girls and cow's milk (99.2%) was the most common trigger. Twenty-four percent of the patients had multiple food allergies and had more common antibiotic use (41.9% vs 11.8%), atopic dermatitis (21% vs 10.2%), wheezing (11.3% vs 1.5%), colic (33.8% vs 11.2%), and IgE sensitization (50% vs 13.5%) compared to the single-food allergic group (P < 0.001, P = 0.025, P = 0.003, P < 0.001, respectively). In multivariate logistic regression analysis, presence of colic (odds ratio [OR]: 5.128, 95% confidence interval [CI]: 1.926-13.655, P = 0.001), IgE sensitization (OR: 3.964, 95% CI: 1.424-11.034, P = 0.008), and having allergy to multiple foods (OR: 3.679, 95% CI: 1.278-10.593, P = 0.001] were found to be risk factors for continuing disease after 1 year of age. CONCLUSION: Although most children achieve tolerance at 1 year of age, IgE sensitization, allergy to multiple foods, and presence of colic were risk factors for persistent course and late tolerance. In this context, these children may require more close and extended follow-up.

How to manage anal ulcerations and anorectal stenosis in Crohn's disease: algorithm-based decision making : French National Working Group Consensus 2018.

The French National Society of Coloproctology established national recommendations for the treatment of anoperineal lesions associated with Crohn's disease. Treatment strategies for anal ulcerations and anorectal stenosis are suggested. Recommendations have been graded following international recommendations, and when absent professional agreement was established. For each situation, practical algorithms have been drawn.

[Diagnostic validity of fecal occult blood test in infants with food protein-induced allergic proctocolitis]. / Estudio de validez diagnóstica de la prueba de hemorragia oculta fecal en lactantes con proctocolitis alérgica inducida por proteína alimentaria.

INTRODUCTION: Food protein-induced allergic proctocolitis (FPIAP) is the most frequent presenta tion of non-IgE mediated food allergy (FA). The diagnosis is made by oral food challenge, however, non-invasive diagnostic tests are not available. In Chile, the fecal occult blood test (FOBT) is fre quently used to confirm FPIAP, however, there are no studies that support this practice. OBJECTIVE: To establish the diagnostic validity of FOBT in the evaluation of infants with FPIAP. PATIENTS AND METHOD: Case-control study with prospective recruitment of infants with rectal bleeding and suspicion of FPIAP, and controls were healthy infants, in whom the FOBT was conducted. All cases underwent an elimination diet, after which the diagnosis of FPIAP was confirmed by oral food cha llenge. RESULTS: 25 cases and 29 controls were included without significant differences in age, gen der, type of delivery, feeding, and maternal age. The cases had higher rates of allergic comorbidities, medication use, and family history of allergy. The FOBT was positive in 84% of cases and in 34% of controls (p < 0.001). The sensitivity of the FOBT for the diagnosis of FPIAP was 84%, specificity was 66%, positive predictive value 68%, and the negative predictive value 83%. The area under the ROC curve was 0.75 (CI 95% 0.61-0.88). CONCLUSIONS: Although the FOBT has an adequate sensitivity to diagnose FPIAP in infants with rectal bleeding, this test had abnormal results in more than a third of healthy infants. Therefore, the routine use of FOBT is not recommended for the diagnosis of FPIAP.

Estudio de validez diagnóstica de la prueba de hemorragia oculta fecal en lactantes con proctocolitis alérgica inducida por proteína alimentaria / Diagnostic validity of fecal occult blood test in infants with food protein-induced allergic proctocolitis

Resumen: Introducción: La proctocolitis alérgica inducida por proteína alimentaria (PCA) es la forma más fre cuente de alergia alimentaria no mediada por IgE. El diagnóstico se realiza por prueba de provocación oral, sin embargo, no existe una prueba diagnóstica no invasiva para su diagnóstico. Frecuentemente en Chile se utiliza la prueba de hemorragia oculta fecal (PHOF) para confirmar PCA, pero no hay estudios que respalden su indicación. Objetivo: Determinar la validez diagnóstica de la PHOF en la evaluación de lactantes con PCA. Pacientes y Método: Estudio de casos y controles con recluta miento prospectivo de lactantes con rectorragia y sospecha de PCA y lactantes sanos, en quienes se realizó una PHOF. Se indicó dieta de exclusión a los casos y luego se confirmó diagnóstico de PCA mediante contraprueba. Resultados: Se incluyó a 25 casos y 29 controles sin diferencias signi ficativas en edad, sexo, tipo de parto, alimentación o edad materna. Los casos presentaron con mayor frecuencia comorbilidades alérgicas, uso de medicamentos y antecedentes familiares de alergia. La PHOF fue positiva en 84% de casos y en 34% de controles (p<0,001). La sensibilidad de la PHOF para diagnosticar PCA fue 84%, especificidad 66%, valor predictivo positivo 68% y valor predictivo nega tivo 83%. El área bajo la curva ROC fue de 0,75 (IC 95% 0,61-0,88). Conclusiones: Si bien la PHOF tiene sensibilidad adecuada para detectar PCA en lactantes con rectorragia, resulta alterada en más de un tercio de lactantes sanos por lo que no se recomienda su uso habitual para el diagnóstico de PCA.

Abstract: Introduction: Food protein-induced allergic proctocolitis (FPIAP) is the most frequent presenta tion of non-IgE mediated food allergy (FA). The diagnosis is made by oral food challenge, however, non-invasive diagnostic tests are not available. In Chile, the fecal occult blood test (FOBT) is fre quently used to confirm FPIAP, however, there are no studies that support this practice. Objective: To establish the diagnostic validity of FOBT in the evaluation of infants with FPIAP. Patients and Method: Case-control study with prospective recruitment of infants with rectal bleeding and suspicion of FPIAP, and controls were healthy infants, in whom the FOBT was conducted. All cases underwent an elimination diet, after which the diagnosis of FPIAP was confirmed by oral food cha llenge. Results: 25 cases and 29 controls were included without significant differences in age, gen der, type of delivery, feeding, and maternal age. The cases had higher rates of allergic comorbidities, medication use, and family history of allergy. The FOBT was positive in 84% of cases and in 34% of controls (p < 0.001). The sensitivity of the FOBT for the diagnosis of FPIAP was 84%, specificity was 66%, positive predictive value 68%, and the negative predictive value 83%. The area under the ROC curve was 0.75 (CI 95% 0.61-0.88). Conclusions: Although the FOBT has an adequate sensitivity to diagnose FPIAP in infants with rectal bleeding, this test had abnormal results in more than a third of healthy infants. Therefore, the routine use of FOBT is not recommended for the diagnosis of FPIAP.

Quantitative MRI in murine radiation-induced rectocolitis: comparison with histopathological inflammation score.

Murine radiation-induced rectocolitis is considered to be a relevant animal model of gastrointestinal inflammation. The purpose of our study was to compare quantitative MRI and histopathological features in this gastrointestinal inflammation model. Radiation rectocolitis was induced by localized single-dose radiation (27 Gy) in Sprague-Dawley rats. T2 -weighted, T1 -weighted and diffusion-weighted MRI was performed at 7 T in 16 rats between 2 and 4 weeks after irradiation and in 10 control rats. Rats were sacrificed and the histopathological inflammation score of the colorectal samples was assessed. The irradiated rats showed significant increase in colorectal wall thickness (2.1 ± 0.3 mm versus 0.8 ± 0.3 mm in control rats, P < 0.0001), normalized T2 signal intensity (4 ± 0.8 versus 2 ± 0.4 AU, P < 0.0001), normalized T1 signal intensity (1.4 ± 0.1 versus 1.1 ± 0.2 AU, P = 0.0009) and apparent and pure diffusion coefficients (ADC and D) (2.06 × 10-3 ± 0.34 versus 1.51 × 10-3 ± 0.23 mm2 /s, P = 0.0004, and 1.97 × 10-3 ± 0.43 mm2 /s versus 1.48 × 10-3 ± 0.29 mm2 /s, P = 0.008, respectively). Colorectal wall thickness (r = 0.84, P < 0.0001), normalized T2 signal intensity (r = 0.85, P < 0.0001) and ADC (r = 0.80, P < 0.0001) were strongly correlated with the histopathological inflammation score, whereas normalized T1 signal intensity and D were moderately correlated (r = 0.64, P = 0.0006, and r = 0.65, P = 0.0003, respectively). High-field MRI features of single-dose radiation-induced rectocolitis in rats differ significantly from those of control rats. Quantitative MRI characteristics, especially wall thickness, normalized T2 signal intensity, ADC and D, are potential markers of the histopathological inflammation score.