The significance of biomarkers of inflammation in predicting the activity of lupus nephritis

Background: Lupus nephritis (LN) is one of the most severe manifestations of systemic lupus erythematosus (SLE). There are increased studies examining the role of different markers that would facilitate diagnosis, LN activity monitoring, relapse occurrence, and the right time to introduce maintenance therapy. We aimed to examine the importance of determining the neutrophil/lymphocyte ratio (NLR), platelet/lymphocyte ratio (PLR), systemic immuneinflammatory index (SII) and systemic inflammatory response index (SIRI) in LN, comparing their significance with other standard parameters of active disease. Methods: The clinical examination included 66 patients (34 with active and 32 with LN in remission) and 23 healthy controls. The investigated parameters were CRP, CBC, creatinine, albumin, GFR, C3, C4, ANA, anti-ds DNA Ab, in urine: sediment analysis, SLEDAI/r, proteinuria 24h and Up/cre. We determined the derived markers: NLR, PLR, SIRI, and SII and their correlation with other parameters of active disease. Results: Comparing the group with active LN with LN in remission and the control group, a statistically significant difference was obtained for CRP (p=0.004) and RBW and haemoglobin, albumin, C3, ANA and anti-ds DNA Ab (p<0.001) and for urinary parameters, SLEDAI/r, proteinuria 24h and Up/cre ratio. Comparing the markers: NLR, PLR, SIRI, and SII between the groups, a significant difference can be observed for all selected parameters; for NLR, it was the most pronounced (p<0.001). In active LN, NLR correlated with CRP, creatinine, SLEDAI/r and proteinuria 24h, PLR with ANA, SIRI with CRP, creatinine, GFR, C3, anti-ds DNA Ab, and SII with CRP. NLR in collective group LN, was the parameter with the highest significance in correlations with C3, albumin, SLEDAI/r and proteinuria (p=0.000), ANA (p=0.001), anti-ds DNA Ab (p=0.004) and Up/cre (p=0.018). Conclusion: Our results indicate that NLR, PLR, SIRI, and SII are elevated in the group of patients with active LN and that the correlations of those biomarkers with other activity parameters can be significant for evaluating renal lesions in LN.