LncRNA LUCAT1 and NR4A2 as promising blood-based biomarkers for Crohn’s disease among Egyptian patients: a case–control study

Abstract

Abstract Background The pathophysiological basis of Crohn’s disease (CD) involves a persistent immune imbalance leading to sustained inflammatory activity. Despite the availability of biomarkers, invasive procedures remain central to diagnosis and monitoring. Recently, long non-coding RNAs (lncRNAs) have been highlighted as important modulators of immune and inflammatory signaling in CD. Lung cancer–associated transcript 1 (LUCAT1) may modulate immune responses through regulation of the anti-inflammatory factor NR4A2. Objective This study aimed to evaluate circulating LUCAT1 and NR4A2 as potential non-invasive biomarkers for assessing CD and its disease activity. Methods In this case-control study, 60 subjects were enrolled, comprising 40 patients diagnosed with CD and 20 controls. According to clinical, laboratory, and endoscopic evaluation, CD patients were further subdivided into active and inactive subgroups. Circulating plasma LUCAT1 expression was quantified using qRT-PCR (2^-ΔΔCt method), and NR4A2 protein concentrations were measured by ELISA. Results Active CD patients exhibited significantly elevated plasma LUCAT1 expression (median: 181.8; range: 44.52–858.7) and reduced NR4A2 levels (median: 5152.5 pg/ml; range: 4364.5–6252.5) compared with controls and inactive patients; however, inactive CD patients did not differ significantly from healthy individuals. For differentiating active from inactive CD, LUCAT1 showed 85% sensitivity and 60% specificity (AUC = 0.743), while NR4A2 demonstrated 80% sensitivity and 75% specificity (AUC = 0.730). The combined LUCAT1–NR4A2–fecal calprotectin panel achieved the highest diagnostic performance (AUC = 0.904, sensitivity 97.5%, specificity 65%). Conclusion Circulating LUCAT1 and NR4A2 may be associated with disease activity in CD rather than serving as standalone diagnostic markers. While neither biomarker alone demonstrates sufficient diagnostic accuracy, their combination with fecal calprotectin may improve sensitivity for detecting active disease. Further validation in larger cohorts is required before clinical application.