Neutrophil-lymphocyte ratio in systemic lupus erythematosus disease: a retrospective study.

Background: Systemic lupus erythematosus (SLE) is a chronic autoimmune disease. Lupus nephritis (LN) is an important cause of morbidity and even mortality in patients with SLE. Some evidences suggest that neutrophil-lymphocyte ratio (NLR) associated with different inflammatory malignancies, ischemic injury and cardiovascular disease. Few scholars have investigated the relationship between NLR and SLE. This study aims to evaluate the role of NLR in SLE without nephritis and LN patients.

Methods: A total of 228 subjects were participated in this study. 79 diagnosed with SLE in patients group and 149 healthy age-and sex-matched in control group. In patient team, 20 of them were diagnosed with LN.

Results: The SLE without nephritis group showed significantly higher NLR than control group (control=2.00±0.76, SLE=4.26±3.38, P<0.001), and the NLR values of the patients with LN were higher than those of the patients without LN (SLE=4.26±3.38, LN=7.21±6.01, P<0.001). Receiver-operating characteristics analysis (ROC) of NLR to predict SLE showed that the area under the curve (AUC) was 0.757. The cutoff value using the ROC curve was 3.13 (sensitivity, 0.574; specificity, 0.926; 95% confidence interval (CI), 0.668-0.845; P<0.001). While ROC analysis of NLR to predict LN showed that the AUC was 0.828). Logistic regression analysis showed that SLE without nephritis and LN were independently related to NLR.

Conclusion: NLR is independently associated with SLE, and it may be a promising marker that reflects renal involvement in patients with SLE.