The ratio of neutrophil to lymphocyte as a potential marker of clinicopathological activity for lupus nephritis.

Abstract

The ratio of neutrophil to lymphocyte (NLR) is a novel inflammatory factor that is elevated in systemic lupus erythematosus (SLE). However, the relationship between NLR and renal pathological manifestations in patients with lupus nephritis (LN) has not been investigated. A retrospective study included 240 SLE patients, in which 186 patients with renal involvement and 124 LN patients underwent renal biopsy, 125 healthy volunteers and 125 chronic kidney disease (CKD) controls. Patients with SLE disease activity 2000 (SLEDAI-2K) > 9 and ≤ 9 were defined as severely active and mildly active, respectively. Clinical parameters and renal pathological data were collected from medical records. The correlations between NLR and clinicopathological features were analyzed. The NLR of SLE group was significantly higher than that of the sex-age matched control groups. Patients with nephritis had higher NLR levels than those without nephritis (P = 0.044). Increased NLR was observed in severely active group compared to mildly active group (P = 0.020). NLR was significantly positively related with SLEDAI score, Renal SLEDAI score, C-reactive protein (CRP), 24-h urine protein, renal activity index (AI), cellular crescents and tubular atrophy, and negatively correlated with serum albumin. NLR was significantly decreased after treatment. Based on the receiver operating characteristic (ROC) curve, the best NLR cut-off value to predict severe activity of SLE and cellular crescents in renal pathology was 2.19 and 3.16, respectively. NLR may be a non-invasive and potential inflammatory marker in evaluating clinical and renal pathological activity in LN patients.