Background: NLR (neutrophil to lymphocyte ratio), PLR (platelet to lymphocyte ratio), and SII (systemic immune-inflammation index) are valuable tools for assessing inflammation and systemic immune responses. Some studies also found that NLR and PLR contribute to SLE disease activity monitoring and infection differential diagnosis. However, there was no exploration in longitudinal cohort during the induction phase of LN.

Objectives: To evaluate the value of NLR, PLR, and SII in reflecting disease activity and induction therapy remission in patients with LN.

Methods: Active LN patients from STAR cohort were enrolled. We analyzed the trends of complete blood count parameters with Generalized Estimated Equation. Bivariate correlation analyses, Chi-square tests, t-tests and logistic regression were employed to assess variable associations and identify prognostic factors for LN remission.

Results: 310 active LN patients were enrolled in the study. All patients had active lupus with SLEDAI-2K 17.1±6.1, median UTP level of 3.1 (1.5, 5.4) g. During the 12-month follow-up of induction therapy, NLR and PLR showed a decreasing trend. Both baseline NLR and SII were positively correlated with baseline 24h-urine protein (UTP) and serum creatinine (SCr) levels (r=0.112-0.148, p< 0.05 for all). Patients with hematuria [4.8 (3.1, 8.1) vs. 4.0 (2.6, 6.5), p = 0.024] and pyuria [5.4 (3.4, 8.8) vs. 3.8 (2.6, 6.6), p < 0.001] had significantly higher baseline NLR. 159 (51.3%) patients performed kidney biopsy, and baseline NLR and SII were positively correlated with the activity index (AI) score of renal pathology (NLR: r =0.244, p=0.013; SII: r =0.199, p=0.043) (Table 1). Futhermore, the changes of NLR and SII were also positively correlated with changes in UTP and SCr during 6 and 12 months (r=0.143-0.175, p<0.05 for all). Nevertheless, neither of baseline NLR, PLR, or SII could predict renal remission at 6 months.

Conclusion: Our findings suggested that NLR and SII were valuable indicators of disease activity in LN, correlating with UTP，SCr and AI score of renal pathology. NLR, PLR and SII provided us a quick, simple and cost-effective supervision way in monitoring and managing LN patients.

REFERENCES: [1] Gasparyan AY, Ayvazyan L, Mukanova U, Yessirkepov M, Kitas GD. The Platelet-to-Lymphocyte Ratio as an Inflammatory Marker in Rheumatic Diseases. Ann Lab Med. 2019 Jul; 39(4):345-357.

[2] Broca-Garcia BE, Saavedra MA, Martinez-Bencomo MA, et al. Utility of neutrophil-to-lymphocyte ratio plus C-reactive protein for infection in systemic lupus erythematosus. Lupus. 2019 Feb; 28(2):217-222.

[3] Abdalhadi S, Khalayli N, Al-Ghotani B, Kudsi M. Systemic lupus erythematosus disease activity and neutrophil-to-lymphocyte ratio and platelet-to-lymphocyte ratio: a cross-sectional case-control study. Ann Med Surg (Lond). 2023 May; 85(5):1448-1453.

[4] Cho J, Liang S, Lim SHH, Lateef A, Tay SH, Mak A. Neutrophil to lymphocyte ratio and platelet to lymphocyte ratio reflect disease activity and flares in patients with systemic lupus erythematosus - A prospective study. Joint bone spine. 2022 Jul; 89(4):105342.

Acknowledgements: NIL.

Disclosure of Interests: None declared.

© The Authors 2025. This abstract is an open access article published in Annals of Rheumatic Diseases under the CC BY-NC-ND license ( http://creativecommons.org/licenses/by-nc-nd/4.0/ ). Neither EULAR nor the publisher make any representation as to the accuracy of the content. The authors are solely responsible for the content in their abstract including accuracy of the facts, statements, results, conclusion, citing resources etc.