POS0480 ASSOCIATION OF NEUTROPHIL LYMPHOCYTE AND PLATELET LYMPHOCYTE RATIOS WITH JOINT INFLAMMATION IN RHEUMATOID ARTHRITIS
Authors: D. Pearce-Fisher, D. Orange, B. Mehta, D. Jannat-Khah, S. Goodman
Journal: Annals of the Rheumatic Diseases (2021)

Background: Some patients with rheumatoid arthritis (RA) have high disease activity scores (DAS) and low synovial inflammation, and others have high synovial inflammation and low DAS (subclinical synovitis)[1]. It would be clinically useful to identify blood biomarkers of synovial inflammation. Neutrophil-lymphocyte (NLR) and platelet-lymphocyte ratios (PLR) have been reported to distinguish RA patients with moderate/high DAS28 scores from low DAS28 [2]. However, it is not known if these inexpensive, accessible tests are associated with inflammation in synovial tissue at the histological level. Objectives: The objective of this study was to evaluate the relationship of pre-operative NLR and PLR with synovial inflammation of the operative joint in RA patients undergoing arthroplasty. Methods: 230 patients meeting ACR/EULAR 1987 and/or 2010 criteria were recruited prior to elective total hip, knee, shoulder, and elbow replacement. Demographics, RA characteristics, medications, disease activity, and routine tests including complete blood tests (CBC) were collected pre-operatively. Hematoxylin and eosin (H&amp;E) stains were prepared from the synovium of the operative joint and systematically scored by a pathologist as described previously [3]. Synovial lymphocytic inflammation was graded as none, mild, moderate, marked, or band-like. Linear regression was performed to distinguish differences in the NLR, PLR, and CRP in patients with synovial lymphocytic inflammation (SLI). Results: As expected, patients on glucocorticoids (GCs) had higher NLR (mean 5.52 (SD 7.68) vs mean 2.82 (SD 1.66) (p&lt;0.001) and higher PLR (mean 233.73 (SD 237.21) vs (mean 162.93 (SD 65.35)) (p-value=0.04)) and those patients (N=92) were therefore excluded from down-stream analyses. On the remaining 138 patients, we tested for associations of PLR, NLR and CRP with SLI using linear regression. In all the models the highest category for synovial lymphocytic inflammation was found to be statistically significantly associated with NLR, PLR and CRP, separately (Table 1). Conclusion: NLR, PLR and CRP are associated with high synovial lymphocytic inflammation of the operative joint. This suggests that these inexpensive, routinely performed blood tests may be a useful blood biomarker of synovial inflammation. References: [1]Orange, D.E. et al. Histologic and Transcriptional Evidence of Subclinical Synovial Inflammation in Patients With Rheumatoid Arthritis in Clinical Remission. Arthritis Rheumatol. 71(7): 1034-1041 (2019). [2]Lee, Y.H. Association between the Neutrophil-to-lymphocyte Ratio, and Platelet-to-lymphocyte Ratio and Rheumatoid Arthritis and their Correlations with the Disease Activity: A Meta-analysis. J Rheum Dis. 25(3):169-178 (2018). [3]Orange, D. E. et al. Identification of Three Rheumatoid Arthritis Disease Subtypes by Machine Learning Integration of Synovial Histologic Features and RNA Sequencing Data. Arthritis Rheumatol. Hoboken NJ 70: 690–701 (2018). Table 1. Results from linear regressions evaluating the association of NLR, PLR, and CRP with synovial lymphocytic inflammation. Linear regression Results NLR PLR CRP Synovial Lymphocytic Inflammation Coef (95% CI) Coef (95% CI) Coef (95% CI) None Reference reference reference Mild 0.31 (-0.51, 1.13) 26.54 (-8.83, 61.90) -1.00 (-2.37, 0.36) Moderate 0.73 (-0.18, 1.64) 28.66 (-10.22, 67.53) 0.46 (-1.09, 2.01) Marked 0.21 (-0.80, 1.22) 24.62 (-22.80, 72.05) 0.81 (-0.87, 2.49) Band-like 1.92 (0.81, 3.02 ) 80.42 (31.46, 129.38 ) 2.32 (0.49, 4.16 ) OR= Odds ratio, Coef = Coefficient, NLR= neutrophil lymphocyte, PLR= platelet lymphocyte ratio, CRP= C-reactive protein All significant associations are bolded. Disclosure of Interests: Diyu Pearce-Fisher: None declared, Dana Orange Consultant of: Astra Zeneca/MedImmune and Pfizer, Bella Mehta Consultant of: Novartis, Deanna Jannat-Khah: None declared, Susan Goodman Consultant of: UCB, Grant/research support from: Novartis, Horizon Pharmaceuticals