Serum a proliferation-inducing ligand and MicroRNA-223 are associated with rheumatoid arthritis: diagnostic and prognostic implications

BACKGROUND: Current blood-based tests for rheumatoid arthritis (RA) have inherent limitations, necessitating the need for additional new biomarkers for its diagnosis and monitoring disease activity and responsiveness to therapy. MicroRNAs (miRNAs) and a proliferation-inducing ligand (APRIL) are deregulated in RA and were linked to its pathogenesis. This study investigated serum levels of APRIL, miR-223 and miR-155 in RA patients, their potential as diagnostic and prognostic biomarkers, and their correlation with disease activity and clinicopathological data. METHODS: One hundred and twenty Egyptian patients with RA and 130 healthy controls were included. Serum miRNAs and APRIL were assayed by RT-qPCR and ELISA, respectively. RESULTS: Serum APRIL and miR-223 were significantly upregulated, while miR-155 was unchanged in RA patients compared to controls. Serum miR-223 discriminated RA patients from controls with AUC = 0.85, whereas serum APRIL superiorly distinguished the two groups with AUC = 1 (sensitivity and specificity = 100% at cutoff> 4.19 ng/ml) by receiver-operating-characteristic analysis. Serum miR-223 was a significant predictor for RA diagnosis in multivariate logistic regression analysis. In RA group, serum APRIL was positively correlated with disease activity score (DAS28-CRP). Serum miR-223 expression was positively correlated with serum miR-155, APRIL levels and with the presence of subcutaneous nodules. Serum miR-155 levels were correlated with antinuclear antibody titer in reverse direction. CONCLUSION: Our results suggest serum APRIL and miR-223 could serve as potential biomarkers of RA, with miR-223 as a predictor of RA risk and APRIL as an excellent biomarker of disease activity. Our data could be implicated for accurate and blood-based non-invasive diagnosis and prognosis of RA.