Urine Phenylacetylglutamine Determination in Patients with Hyperphenylalaninemia.

Phenylketonuria (PKU), an autosomal-recessive inborn error of phenylalanine (Phe) metabolism is the most prevalent disorder of amino acid metabolism. Currently, clinical follow-up relies on frequent monitoring of Phe levels in blood. We hypothesize that the urine level of phenylacetylglutamine (PAG), a phenyl-group marker, could be used as a non-invasive biomarker. In this cross-sectional study, a validated liquid chromatography coupled to tandem mass spectrometry (LC-MS) method was used for urinary PAG quantification in 35 participants with hyperphenylalaninemia (HPA) and 33 age- and sex-matched healthy controls. We have found that (a) PKU patients present higher urine PAG levels than healthy control subjects, and that (b) there is a significant correlation between urine PAG and circulating Phe levels in patients with HPA. In addition, we show a significant strong correlation between Phe levels from venous blood samples and from capillary finger-prick dried blood spot (DBS) samples collected at the same time in patients with HPA. Further research in order to assess the potential role of urine PAG as a non-invasive biomarker in PKU is warranted.

Pharmacogenetics of trough serum anti-TNF levels in paediatric inflammatory bowel disease.

AIMS: Identifying DNA variants associated with trough serum anti-tumour necrosis factor (TNF) levels could predict response to treatment in inflammatory bowel disease (IBD). To date, no specific studies have been performed in children. The aim of this study was to identify genetic variants associated with trough serum anti-TNF levels and whether these variants are differential markers for infliximab and adalimumab. METHODS: We included 154 children (age < 18 years) from 17 hospitals who had been diagnosed with IBD and actively treated with infliximab or adalimumab. Twenty-one polymorphisms were genotyped using real-time PCR. Trough serum anti-TNF levels were measured using enzyme-linked immunosorbent assay (ELISA). The association between DNA polymorphisms and the therapeutic range or the absolute values of anti-TNF drugs was analysed by Fisher exact test, student's t-test and logistic regression. RESULTS: The variants rs5030728 (TLR4) and rs11465996 (LY96) were associated with subtherapeutic infliximab levels. rs1816702 (TLR2) was associated with supratherapeutic levels and rs3397 (TNFRSF1B) with subtherapeutic levels of adalimumab (P < .05). In addition, rs1816702 (TLR2) and rs2569190 (CD14) were associated with absolute values of trough serum adalimumab, and rs2569190 (CD14) was associated with absolute values of trough serum adalimumab and infliximab (P < .05). CONCLUSION: Genotyping of these DNA variants before starting treatment may help to select the best anti-TNF drug in paediatric patients. The SNP rs1816702 is the most promising marker for tailoring the anti-TNF regimen in children with IBD. For the first time, DNA variants are associated with trough serum anti-TNF levels.

Genetic Predictors of Long-term Response to Antitumor Necrosis Factor Agents in Pediatric Inflammatory Bowel Disease.

OBJECTIVES: Inflammatory bowel disease (IBD) is more complex in children and they will have to live with the disease for much longer. For this reason, it is necessary to optimize treatment. The polymorphisms associated with the response to anti-tumor necrosis factor (TNF) drugs in adults with IBD have not been analyzed in children. The aim of the study was to identify genetic variants associated with the long-term response to anti-TNF drugs in children with IBD. METHODS: An observational, longitudinal, ambispective cohort's study was conducted. We recruited 209 anti-TNF-treated children diagnosed with IBD and genotyped 21 polymorphisms previously studied in adults with Crohn disease (CD) using real-time PCR. The association between single-nucleotide polymorphisms (SNPs) and time-to-failure was analyzed using the log-rank test. RESULTS: After multivariate analysis, 3 SNPs in IL10, IL17A and IL6 were significantly associated with response to anti-TNF treatment among patients diagnosed with CD (rs1800872-HR, 4.749 (95% confidence interval [CI] 1.156-19.517), P value < 0.05; rs2275913-HR, 0.320 [95% CI 0.111-0.920], P value  < 0.05; and rs10499563-HR, 0.210 [95% CI 0.047-0.947], P value 0.05, respectively). None of these SNPs were associated with response to infliximab in adults diagnosed with CD. Among patients diagnosed with ulcerative colitis (UC), 1 SNP in LY96 was significantly associated with response to anti-TNF treatment (rs-11465996-HR, 10.220 [95% CI 1.849-56.504] P value < 0.05). CONCLUSIONS: Genotyping of these DNA variants before starting treatment may help to identify children who are long-term responders to anti-TNF drugs, and thus tailor treatment of pediatric IBD.

Factors Associated with the Development of Immune Tolerance in Children with Cow's Milk Allergy.

INTRODUCTION: Cow's milk allergy (CMA) is a common diagnosis in infants, requiring the exclusion of cow's milk until tolerance is recovered. In the present study, we aim to determine which factors are associated with the development of tolerance. METHODS: Retrospective, observational study of subjects who underwent the same clinical follow-up methodology. We studied 245 cases of CMA (125 IgE-mediated and 120 non-IgE-mediated). The following variables were analysed: age at diagnosis, gender, type of delivery, type of feeding received, feeding during the first months of life, clinical features, and type of feed received as treatment: casein hydrolysates or casein hydrolysates with Lactobacillus rhamnosus GG (LGG). RESULTS: Factors associated with earlier tolerance were non-IgE-mediated CMA (HR = 2.92; 95% CI: 2.20-3.88) and patients receiving casein hydrolysate with LGG (HR = 1.79; 95% CI: 1.33-2.42). Later tolerance was associated with caesarean delivery (HR = 0.78; 95% CI: 0.58-1.05) and breastfeeding for a period of at least 3 days (HR = 0.64; 95% CI: 0.44-0.93). The multivariate study shows that the type of formula (HR = 1.61; 95% CI: 1.19-2.18) and the type of CMA (HR = 2.82; 95% CI: 2.12-3.85) have an effect on the recovery time. Casein hydrolysates with LGG reduces the recovery time in IgE-mediated (HR = 1.88; 95% CI: 1.17-3.01) and non-IgE-mediated CMA (HR = 1.46; 95% CI: 0.98-2.17). CONCLUSIONS: Tolerance acquisition is faster in non-IgE-mediated CMA subjects and in those who received casein hydrolysate with LGG.

A new score to predict allergic march in patients with IgE-mediated cow milk allergy.

Background: Cow milk allergy (CMA) is the most common food allergy in infants. Some patients will express, in the future, other allergic diseases (allergic march). Objective: To evaluate if a new scoring system could determine the risk of developing allergic march. Methods: A retrospective observational cohort study of subjects who were immunoglobulin E (IgE) mediated was conducted. We defined a risk score for atopy (RSA), including clinical and laboratory variables. Three risk groups were defined according to the RSA. We defined as dependent variables atopy (one or more allergic diseases) and atopy+ (two or more allergic diseases). A multivariate logistic regression model was created, which included RSA and the type of formula (high-grade extended hydrolyzed formula [EHF] with Lactobacillus rhamnosus GG (LGG), high-grade EHF without LGG, and other formulas). Results: A total of 211 patients were recruited. When we analyzed the risk of atopy+, we found an increased risk for RSA intermediate-risk (odds ratio [OR 2.08] [95% confidence interval {CI}, 0.95-4.56) and high-risk (OR 24.74 [95% CI, 6.26-97.73]) groups, and a decreased risk for the subjects fed with high-grade EHF (OR 0.42 [95% CI, 0.20-0.87]) and also in those subjects fed with high-grade EHF plus LGG (OR 0.30 [95% CI, 0.09-0.98]). Conclusion: RSA is a simple and useful tool to predict the risk of developing other allergic diseases in patients with IgE-mediated CMA.

Association between Caesarean Delivery and Isolated Doses of Formula Feeding in Cow Milk Allergy.

BACKGROUND: Cow milk allergy (CMA) is the most common food allergy in breastfed infants. The aim of this study is to verify whether certain perinatal factors may influence the development of CMA immunoglobulin E (IgE)+. METHODS: A retrospective, observational study of case and control groups was carried out. Information was collected of patients with CMA IgE+ from our department during the years 1990-2013. Patients of the same age and sex were recruited for the control group. Information on the following variables was collected: sex, age, pregnancy tolerance, duration of pregnancy, type of delivery, isolated doses of formula feeding in hospital (FFH), duration of breastfeeding, and family history of allergy (defined as ≥1 first-degree family member with allergic disease). Statistical analysis was performed using multivariate logistic regression techniques. RESULTS: A total of 211 cases were included in this study. Multivariate analysis showed an influence of duration of breastfeeding, FFH to be a risk factor (OR 4.94; 95% CI 2.68-9.08), especially in caesarean delivery (OR 11.82; 95% CI 2.64-47.50), and prematurity (OR 0.29; 95% CI 0.09-0.92) to be a protective factor. CONCLUSIONS: Perinatal factors play a key role in the development of CMA IgE+, with an influence of breastfeeding duration, FFH and caesarean delivery as risk factors and prematurity as a protective factor. While family history had no important role, environmental factors were more decisive.