Abstract: Objective To compare serum levels of lactoferrin (LF) in healthy subjects and patients with systemic lupus erythematosus (SLE). To analyze the cause for reduced LF levels in SLE patients. Methods Serum concentrations of lactoferrin in healthy children (n = 38), healthy adults (n = 46), pediatric SLE patients (n = 38), adult SLE patients (n = 46), healthy people with ages from 1 to 80 (n = 80), IgA nephropathy patients (n = 29) and other kidney patients (n = 19) were measured by ELISA. Total protein concentrations in serum were measured by BCA. An unpaired t test was performed to analyze the differences between two groups and Spearman's correlation analysis was performed to analyze the relationship between the levels of LF and total protein. Results Serum concentrations of LF in both pediatric and adult patients were lower than that in healthy control subjects, patients with IgA nephropathy and other kidney patients (P<0.001). The levels of LF were reduced in people aged over 50. Conclusion LF levels were significantly reduced in SLE patients, which was not caused by the changes of total protein in serum.

Key words: Key words: Systemic Lupus Erythematosus, Lactoferrin, Biomarker