Platelet-to-lymphocyte ratio: a superior prognostic marker for systemic lupus erythematosus compared to neutrophil-to-lymphocyte ratio and systemic immune-inflammation index

Abstract

Objective. Novel inflammatory indices are a potential substitute for traditional markers which their correlation and clinical application in different autoimmune diseases are still in question. In this study, we evaluated the association of platelet-to-lymphocyte ratio (PLR), neutrophil-to-lymphocyte ratio (NLR), and systemic immune-inflammation index (SII) with systemic lupus erythematosus (SLE) activity. Methods. We included 103 SLE patients in our study, compared to a matched pair of 103 healthy individuals. A blood sample was drawn to measure SII, PLR, NLR, C-reactive protein, erythrocyte sedimentation rate, autoantibodies, and complement levels. Independent sample t-test, chi-square, and Mann-Whitney U test were implemented for variables as appropriate. Linear regression was used to evaluate the factors that predict SLE activity. Results. Our study revealed that NLR, PLR, and SII between SLE patients and the control group were significantly different. SII and NLR were correlated with renal manifestations of SLE. PLR was correlated with SLEDAI, and an independent factor of SLE activity after adjusting for multiple factors, but not NLR and SII. Conclusion. We demonstrated that only PLR was an independent predictor of SLE activity. This may suggest that NLR and SII are more nonspecific inflammatory markers, compared to PLR being prognostic of SLE activity.

Keywords

• systemic lupus erythematosus
• neutrophil-to-lymphocyte ratio
• sledai
• platelet-to-lymphocyte ratio
• disease activity
• systemic immune-inflammation index