Elevated Blood and Urinary ICAM-1 is a Biomarker for Systemic Lupus Erythematosus: A Systematic Review and Meta-Analysis

Background: Systemic lupus erythematosus (SLE) is an autoimmune disease with complex etiology. Intercellular cell adhesion molecule-1 (ICAM-1) is critical for leukocyte adhesion to endothelium and migration out of blood vessels and thus participates in many autoimmune diseases. Previous studies of blood and urinary ICAM-1 in SLE have yielded inconsistent results. Methods: The following databases were searched for studies that compared blood and/or urinary ICAM-1 in SLE patients vs. healthy control subjects, and/or in SLE with active vs. inactive diseases: PubMed, EMBASE, Cochrane Library, China National Knowledge Infrastructure and Web of Science. Standardized mean difference (SMD) and 95% confidence intervals (CI) were calculated using a random-effects model when there was significant heterogeneity (assesses using the Cochrane Q test and I-2 statistics), and using a fixed-effects model otherwise. Publication bias was assessed using funnel plot and egger text. Results: The initial screening yielded a total of 1,215 articles; 22 articles (14 reporting blood ICAM-1, 7 reporting urinary ICAM-1 and 1 reporting both) were included in the meta-analysis. In comparison to healthy controls, SLE patients had elevated urinary ICAM-1 (SMD: 0.711; 95% CI: 0.521, 0.901) as well as blood ICAM-1 (SMD: 0.725; 95% CI: 0.385, 1.065). Blood ICAM-1 did not differ significantly between active and inactive SLE (SMD: 0.396; 95% CI: -0.556, 1.347). Conclusion: Elevated blood and urinary ICAM-1 is a biomarker for SLE, but does not differentiate active and inactive SLE.