Utility of neutrophil-to-lymphocyte ratio plus C-reactive protein for infection in systemic lupus erythematosus

Abstract

Distinction between infection and flare in patients with systemic lupus erythematosus (SLE) is a challenge in clinical practice. Objective To analyze the utility of neutrophil-to-lymphocyte ratio (NLR) plus C-reactive protein (CRP) to differentiate between infection and active disease in patients with SLE. Methods A cross-sectional study of a cohort of patients with SLE was carried out. Blood samples from four groups (patients without infection or active disease, patients with infection, patients with active disease, and patients with both infection and active disease) before therapeutic interventions were analyzed. We excluded patients with current malignancy, pregnancy, ischemic heart disease or use of antimicrobials during previous 7 days. Hematological cell count, CRP and cultures were obtained. We constructed receiver operating characteristic curves; sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) were calculated. Results Forty patients were included. NLR cut-off ≥6.3 had sensitivity 70%, specificity 85%, PPV 83% and NPV 74% to detect patients with non-viral infections. A CRP cut-off ≥7.5 mg/L had sensitivity 90%, specificity 75%, PPV 78% and NPV 88% to detect infections regardless of SLE activity. Combination of CRP plus NLR improves the specificity to 90% and PPV to 88%. Excluding the group with both infection and active disease, CRP plus NLR expands specificity to 95% and NPV to 90%. Conclusion In our experience, levels of CRP, particularly CRP plus NLR, were useful in differentiating patients with SLE from those with suspected non-viral infection regardless of the activity of the disease.

Differential Parameters between Activity Flare and Acute Infection in Pediatric Patients with Systemic Lupus Erythematosus

“…These 185 episodes were divided into 4 groups: infected-active episodes as group A (n = 102; 55%), infected-inactive episodes as group B (n = 11; 6%), noninfected-active episodes as group C (n = 59; 32%), and noninfected-inactive episodes as group D (n = 13; 7%) ( Table 2). In the similar studies of adult SLE patients comparing parameters from the four groups, the trend of our CRP results is the same as three reported literatures [18,28,32]. While the trend of ESR and PCT are also in consistent with those of Schäfer et al and Wang et al, respectively (supplement Fig.…”

“…1). Like the result from Broca-Garcia et al, infected-active group (group A) had the highest values of PLR among all four groups [28].…”

“…This was a rare study focusing on distinguishing are from infection in pediatric-onset SLE patients, and the study design closely approximated real-world clinical practice. Studies similar in design to ours have been reported previously [18,20,21,28,32]. Thus, our study design was similar to those for disease registries derived from the systematic collection of information from patients diagnosed with a particular disease (SLE).…”

“…Based on previous reports [23,[26][27][28][29], data encompassing both clinical and laboratory parameters were collected at each episode according to a standardized clinical protocol (detailed in supplement Table 1). [30,31].…”

Relationship between Neutrophil-to-Lymphocyte Ratio and Systemic Lupus Erythematosus: A Meta-analysis

“…NLR is closely associated with most common inflammatory biomarkers, such as C-reactive protein and erythrocyte sedimentation rate (44)(45)(46)(47)(48)(49). A growing body of evidence suggests that NLR may act as excellent indicator of inflammation status in various diseases, such as Crohn's disease (49), cancer (50,51), infection (52,53), and rheumatic diseases (54)(55)(56). Moreover, numerous studies also reported that NLR was closely related to inflammatory response and SLE disease activity (23)(24)(25)(26)(27)(28)(29)(30)(31)(32)(33)(34)(35).…”