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Role of neutrophil-lymphocyte ratio and platelet-lymphocyte ratio as markers of disease activity in systemic lupus erythematosus patients with or without renal involvement

Background In systemic inflammation, white blood cells show neutrophilia and lymphopenia. The neutrophil-lymphocyte ratio (NLR) and platelet-lymphocyte ratio (PLR) are emerging as key markers for systemic inflammation. This study aims to evaluate NLR and PLR as markers of disease activity in systemic lupus erythematosus (SLE) patients with or without renal involvement.

Methods A cross-sectional study was conducted at Dhaka medical college and hospital (DMCH), national institute of kidney disease and urology (NIKDU), and Bangabandhu Sheikh Mujib medical university (BSMMU). It included 90 newly diagnosed SLE patients (with or without renal involvement) and 30 age- and sex-matched healthy controls. Patients were divided into two groups: active disease SLE disease activity index (SLEDAI score ≥8) and inactive disease (SLEDAI score <8). Data were analyzed using SPSS version 26.

Results Results showed that both NLR and PLR were significantly higher in SLE patients compared to controls (both p<0.001) and were elevated in active disease (both p<0.001). NLR levels were higher in patients with renal involvement (p<0.05). NLR and PLR positively correlated with SLEDAI score, anti-dsDNA, and ESR, and negatively with C3 and C4. NLR differed significantly across lupus nephritis classes and correlated positively with activity index, while PLR did not. For predicting disease activity in SLE with renal involvement, NLR and PLR cut-off values were 2.41 (80% sensitivity, 51.1% specificity) and 178.4 (80% sensitivity, 57.8% specificity), respectively. For SLE without renal involvement, NLR was 2.23 (71.1% sensitivity, 52.02% specificity) and PLR was 159.6 (75.6% sensitivity, 73.3% specificity).

Conclusions NLR and PLR are promising biomarkers for managing SLE patients, irrespective of renal involvement.