Celiac disease (CeD) is an autoimmune condition triggered by gluten in genetically predisposed individuals, affecting all ages. Intestinal permeability (IP) is crucial in the pathogenesis of CeD and it is primarily governed by tight junctions (TJs) that uphold the intestinal barrier’s integrity. The protein zonulin plays a critical role in modulating the permeability of TJs having emerged as a potential non-invasive biomarker to study IP. The importance of this study lies in providing evidence for the usefulness of a non-invasive tool in the study of IP both at baseline and in the follow-up of paediatric patients with CeD. In this single-centre prospective observational study, we explored the correlation between faecal zonulin levels and others faecal and serum biomarkers for monitoring IP in CeD within the paediatric population. We also aimed to establish reference values for faecal zonulin in the paediatric population. We found that faecal zonulin and calprotectin values are higher at the onset of CeD compared with the control population. Specifically, the zonulin levels were 347.5 ng/mL as opposed to 177.7 ng/mL in the control population (p = 0.001), while calprotectin levels were 29.8 μg/g stool compared to 13.9 μg/g stool (p = 0.029). As the duration without gluten consumption increased, a significant reduction in faecal zonulin levels was observed in patients with CeD (348.5 ng/mL vs. 157.1 ng/mL; p = 0.002), along with a decrease in the prevalence of patients with vitamin D insufficiency (88.9% vs. 77.8%). We conclude that faecal zonulin concentrations were higher in the patients with active CeD compared with healthy individuals or those following a gluten-free diet (GFD). The significant decrease in their values over the duration of the GFD suggests the potential use of zonulin as an additional tool in monitoring adherence to a GFD.

Pancreatic ductal adenocarcinoma (PDAC) is characterized by its poor prognosis. The current challenge remains the absence of predictive biomarkers. Cytokines are crucial factors in the pathogenesis and prognosis of PDAC. Furthermore, there is growing interest in differentiating between molecular subtypes of PDAC. The aim of our study is to evaluate the association between the analyzed cytokines and the molecular subtypes of PDAC and to determine their prognostic value. Cytokine levels were measured in 73 patients, and molecular subtypes were analyzed in 34 of these patients. Transforming Growth Factor Beta 2 (TGF-β2) levels were independently associated with the basal-like and null subtypes. In patients with locally advanced and metastatic PDAC, elevated levels of interleukin (IL)-1α, IL-1β, IL-6, IL-8, IL-9, and IL-15 were associated with a higher risk of progression during first-line treatment, and increased levels of IL-1β, IL-6, IL-8, IL-9, and IL-15 were related to increased mortality. Furthermore, a significant association was observed between higher percentiles of IL-6 and IL-8 and shorter progression-free survival (PFS) during first-line treatment, and between higher percentiles of IL-8 and shorter overall survival (OS). In the multivariate analysis, only elevated levels of IL-8 were independently associated with a higher risk of progression during first-line treatment and mortality. In conclusion, the results of our study suggest that cytokine expression varies according to the molecular subtype of PDAC and that cytokines also play a relevant role in patient prognosis.

INTRODUCTION: Therapeutic drug monitoring (TDM) of immunosuppressive drugs is essential to maintain concentrations within narrow therapeutic windows and minimize toxicity. Automated LC–MS/MS platforms can combine the analytical specificity of mass spectrometry with workflow efficiency suitable for routine laboratories. OBJECTIVES: To preliminarily evaluate the analytical performance of the Cobas i601 automated LC–MS/MS system for quantifying tacrolimus, cyclosporine, everolimus, and sirolimus and to compare results with routine immunoassays and an LC–MS/MS method for sirolimus. METHODS: Imprecision, bias, and linearity were assessed according to the Clinical Laboratory Standards Institute (CLSI) EP10-A3 standard using quality-control materials. Method comparison and bias estimation versus the Dimension EXL 200 immunoassays and an LC–MS/MS technique for sirolimus followed the CLSI EP09-A3 standard. Regression analyses and predicted biases at therapeutic range concentrations were compared with allowable limits. RESULTS: The Cobas i601 showed good precision and linearity, meeting manufacturer specifications. The highest coefficients of variations for tacrolimus, everolimus, cyclosporine, and sirolimus were 4.0%, 4.7%, 3.6%, and 4.8%, and the maximum EP10-A3 biases were −7.4%, −3.9%, 4.7%, and 5.4%, respectively. In the method comparison, tacrolimus, everolimus, and cyclosporine showed substantial negative biases versus immunoassays (−22.7%, −38.9%, and −37.5%), exceeding allowable limits. Sirolimus exhibited smaller positive bias relative to the LC–MS/MS method (12.5%). Interchangeability between the methodologies cannot be assumed. CONCLUSION: The Cobas i601 provides reliable automated LC–MS/MS quantification of immunosuppressants, with good precision and linearity. Method-dependent biases highlight the need for careful interpretation during technology transitions. The Cobas i601 shows strong potential for routine LC–MS/MS implementation in TDM in clinical laboratories.

Background and Objectives: Krebs von den Lungen-6 (KL-6) is a promising biomarker of interstitial lung disease (ILD), but data in immune-mediated ILD remain limited. We aimed to evaluate the clinical, functional, and radiological correlates of serum KL-6 levels in a real-world cohort of patients with immune-mediated ILD. Materials and Methods: We conducted a retrospective, cross-sectional, single-center study including adults with multidisciplinary follow-up for immune-mediated ILD and at least one serum KL-6 determination between January 2023 and September 2025. Clinical, laboratory, radiological, and pulmonary function data closest to the index KL-6 measurement were collected. KL-6 was analyzed as both a continuous variable and a categorical variable using a predefined cutoff of 500 U/mL. Correlation analyses and multivariable logistic regression were performed to identify factors independently associated with elevated KL-6 levels. Results: A total of 112 patients were included; 72.3% were women, with a median age of 70 years (IQR 63–77). The most frequent underlying diseases were systemic sclerosis (30.4%), rheumatoid arthritis (25.9%), and inflammatory myopathy (14.3%). Median KL-6 concentration was 770.5 U/mL (IQR 437.3–1148.5). Patients with FVC < 80% predicted and DLCO < 60% predicted had significantly higher KL-6 levels than those with better lung function (p = 0.001 and p = 0.004, respectively). KL-6 levels correlated inversely with DLCO (% predicted) (ρ = −0.388, p < 0.001) and FVC (% predicted) (ρ = −0.328, p < 0.001) but not with the presence of radiological fibrosis. In the multivariable analysis, lower DLCO (% predicted) (OR 0.919, 95% CI 0.884–0.955; p < 0.001) and older age (OR 1.063, 95% CI 1.014–1.115; p = 0.012) were independently associated with elevated KL-6 levels. Conclusions: Elevated serum KL-6 concentrations were associated with impaired gas transfer as measured by DLCO % predicted in this cross-sectional cohort. Longitudinal studies are required to determine whether KL-6 can predict functional decline, disease progression, or clinical outcomes.