Long non-coding RNA (H19) in patients with spondyloarthritis: association with disease parameters and ultrasonographic findings

Abstract
Background
Spondyloarthritis is a well-known chronic inflammatory disorder; despite recent advances, its genetic basis remains poorly understood. Recently, long non-coding RNA (H19) was identified to be associated with various human cancers and studied in some autoimmune diseases. Musculoskeletal ultrasound has been shown to have good sensitivity and specificity in detecting enthesitis. The Belgrade Ultrasound Enthesitis Score (BUSES) has recently been proposed as a comprehensive ultrasound enthesitis scoring system for differentiating between individuals with enthesitis associated with spondyloarthritis and those without spondyloarthritis.

Aim
The current work aimed to study the role of long non-coding RNA (H19) as a potential biomarker in axial spondyloarthritis and its relationship with the different disease parameters (clinical and laboratory), disease activity, and functional status as well as the relation between long non-coding RNA (H19) and articular manifestations using ultrasonographic assessment of enthesitis.

Results
Long non-coding RNA (H19) expression was statistically higher in axial spondyloarthritis patients than controls; there are no statistically significant correlations between long non-coding RNA (H19) relative expression and any of the listed parameters (ESR, CRP, ASDAS-CRP, BASDAI, BASFI, BASMI, BUSES, SPARCC index, mSASSS). As regards the Spearman correlation of Belgrade Ultrasound Enthesitis Score, it showed a statistically significant positive correlation with ASDAS-CRP, BASDAI, and BASMI (p value: 0.002, 0.02, and 0.046, respectively).

Conclusion
Both long non-coding RNA (H19) and Belgrade Ultrasound Enthesitis Score have good discriminative ability between patients with axial spondyloarthritis and normal population; this suggests a possible role in early diagnosis for patients with axial spondyloarthritis who do not fulfill ASAS classification criteria. Their role to monitor the disease activity still needs further studies to be established. Musculoskeletal ultrasound is much more accurate in the assessment of enthesis than clinical examination. Further studies are needed to study the correlation between ultrasonographic entheseal scores and activity markers either clinically or laboratory.