AB1064 UTILITY OF NEUTROPHIL CD64 EXPRESSION, PRESEPSIN, PROCALCITONIN, NEUTROPHIL TO LYMPHOCYTE RATIO AND CRP IN DIFFERENTIATING INFECTIONS FROM FLARES IN SYSTEMIC LUPUS ERYTHEMATOSUS PATIENTS
Authors: M. Kumar Maurya, S. Mukherjee, N. Kamble, A. K. Vijayakumaran, A. Pm, U. Dhakad, P. Kumar
Journal: Annals of the Rheumatic Diseases (2024)

<h3>Background:</h3> Infection is a common and an important morbidity and a significant cause of death in patients with systemic lupus erythematosus. Flares may mimic the acute febrile phase of an infectious process, and the clinical consequences of treating infections with immunosuppressant or flare of the disease with antibiotics may be fatal. <h3>Objectives:</h3> 1.To study usefulness of neutrophil CD64 expression, presepsin, procalcitonin, CRP and neutrophil to lymphocyte ratio to differentiate infections from flares in SLE patients. 2. To study the prevalence of infections in patients of SLE in a tertiary centre of northern India. <h3>Methods:</h3> Study place: The study was conducted between July 2021 to December 2022 in Department of Clinical Immunology and Rheumatology at K.G.M.U. UP, Lucknow. Study design: Observational, cross-sectional study. Duration of study: 1.5 years. Inclusion criteria: 1) Patients with SLE fulfilling ACR/EULAR 2019 Criteria with signs of active disease or infection. 2) Age &gt; 18 years of age. Sample size: 113. FITC mouse Anti Human CD64 kits by BD sciences were used for the tests. Cells were gated on CD45 PerCp vs side scatter. Neutrophilic expression of CD64 was recorded and Mean fluorescence index was calculated for all the samples of cases and controls. Presepsin was performed by sandwitch ELISA. <h3>Results:</h3> A total of 113 patients were recruited over a period of one year and were divided into three groups, bacterial infections (n=26), flare (n= (48) and both (n = 39). Out of 74 infective episodes, most common infection was UTI 39 (52.7%) followed by Pneumonia/LRTI 19 (25.6%). Most common culture grown organism was klebsiella followed by E. coli. ROC curve analysis for optimal cut-offs to differentiate flare from infection for various parameter showed TLC (AUC 0.724, sensitivity 61.5%, specificity 81.2%), Neutrophil CD64 expression (AUC 0.887, sensitivity 80.8%, specificity 81.2%), procalcitonin (AUC 0.931, sensitivity 80.8%, specificity 87.5%), CRP (AUC 0.687, sensitivity 76.9%, specificity. 52.1%), Presepsin (AUC 0.654, sensitivity 61.5, specificity 52.1%), NLR (AUC 0.778, sensitivity 73.1 and 68.8%). We created two models for multivariable logistic regression analysis to avoid redundancy. In one model CD64 expression (MFI), Procalcitonin and DS DNA could significantly predict infections in SLE patients with AUC of 0.958. In another model neutrophil CD64 MFI and SLEDAI 2K could predict infections with an AUC of 0.949. Thus, composite biomarkers could reliably differentiate bacterial infections from flare in patients with SLE. <h3>Conclusion:</h3> Elevated TLC, NLR, CRP, procalcitonin, presepsin, neutrophil CD64 expression and low C3, C4, and anti dsDNA were associated with infections on univariate analysis.• On multivariate analysis, CD64, dsDNA and procalcitonin were significantly predictive of infection with AUC of 0.958 in model 1 and model 2 neutrophil CD64 MFI and SLEDAI 2K could predict infections with an AUC of 0.949. <h3>REFERENCES:</h3> [1] Yuhara T, Takemura H, Akama T, Suzuki H, Yamane K, Kashiwagi H. Predicting infection in hospitalized patients with systemic lupus erythematosus. Intern Med. 1996 Aug;35(8):629-36. <h3>Acknowledgements:</h3> <b>NIL.</b> <h3>Disclosure of Interests:</h3> <b>None declared.</b>