Objective: To investigate the role of neutrophil to lymphocyte ratio (NLR) and platelet to lymphocyte ratio (PLR) as activity markers in systemic lupus erythematosus (SLE) without nephritis and lupus nephritis (LN) patients.

Methods: This study included 60 SLE patients with LN, 60 SLE patients without renal involvement and 30 healthy controls. We analyzed correlations between NLR and PLR and both disease activity and renal affection.

Results: The NLR of SLE patients was much higher than those of the controls. Both ratios showed significantly increased values in SLE patients with active disease. NLR and PLR were positively correlated with SLEDAI, ESR, and CRP and negatively correlated with C4. SLE patients with LN had higher levels of NLR than those without nephritis. NLR showed positive correlations with BUN, serum urea, serum creatinine and 24h urinary protein. We found NLR to be related to anti-ds-DNA level and renal biopsy classes. While PLR was related only to anti ds-DNA. The best NLR to predict SLE active disease was 2.2 and the best PLR cut-off value was 132.9.

Conclusions: NLR and PLR are useful inflammatory markers to evaluate disease activity in SLE patients. Also, NLR could reflect renal involvement in SLE patients and is associated with the different classes of its histological staging.