Serum ornithine to arginine ratio as a novel diagnostic test for rheumatoid arthritis in women

Abstract

Finding specific serum biomarkers linked to rheumatoid arthritis (RA) can help us understand the course of the disease, and the prognosis. Here, we aimed to explore the potential use of arginine, ornithine, tryptophan, citrulline, serotonin and several other biochemical markers for early diagnosis of rheumatoid arthritis (RA). We examined serum samples from 30 controls and 60 RA patients to achieve this goal. According to our findings, there was a statistically significant difference in the serum levels of ornithine and arginine between RA patients and controls, with higher ornithine and lower arginine in RA patients compared to controls. Furthermore, we found that only patients with high disease activity index had considerably greater levels of serotonin. Additionally, we found that using arginine alone can predict RA disease with 96.7% sensitivity and 80.8 % specificity, while ornithine can predict RA disease with 100% sensitivity and 66.7% specificity. Interestingly, the ornithine to arginine ratio (OR/AR) could identify people with RA disease with 100% sensitivity and 83.3% specificity and this clear discrimination is not affected by the disease index or duration. Hence, RA patients can be distinguished using the ornithine to arginine ratio as a biomarker, which has higher specificity than each analyte alone. Our results can undoubtedly serve as a foundation for additional research and multicenter studies in the future to support accurate therapeutic management strategies for RA patients.

Keywords Rheumatoid arthritis, DAS score , Ornithine , Arginine , Serotonin