High Neutrophil-Lymphocyte Ratio Predicts Serious Renal Insufficiency in Patients With Lupus Nephritis

Abstract Background Recently, neutrophil-lymphocyte ratio (NLR), a biomarker used to monitor inflammation and immune response, has been shown to be a prognostic marker in systemic lupus erythematosus (SLE). Objective To investigate the association between pretreatment NLR and renal impairment in patients with lupus nephritis(LN). Methods This retrospective study included 88 LN patients, 51 SLE patients without renal involvement, 79 patients with primary chronic nephritis (CN) and 52 healthy controls (HC). The differentiation was analyzed among these four groups via Whitney U test, and correlations among variables were evaluated in LN patients. Finally, receiver operating characteristic curves (ROC) was performed to evaluate the diagnostic value of NLR in patients with LN. Results Pretreatment NLR of LN patients was significantly higher than that of the other three groups. The NLR was positively associated with complement 3(C3), C4, C-reactive protein (CRP) and serum creatinine (SCr) (C3: r = 0.222, p = 0.042; C4: r = 0.230, p = 0.035; CRP: r = 0.337, p = 0.007; SC: r = 0.408, p < 0.0001) but inversely correlated with IgG (r=-0.226, p = 0.041). NLR level increased with severity of renal impairment. NLR (area under the curve (AUC): 0.785, 95% CI = 0.708–0.862) was useful for diagnosis of LN, and its optimal cutoff was 5.44 (sensitivity: 65.9%, specificity: 86.3%). Conclusions A high NLR was associated with severe renal function impairment in LN patients. NLR would be useful for diagnosis of LN and reflect severity of renal impairment. Thus, evaluating pretreatment NLR could help clinicians identify the potential renal involvement in SLE patients and distinguish LN from CN, so clinicians could conduct early triage and initiate effective management in time.