Serum L-ficolin levels in patients with systemic lupus erythematosus.
ABSTRACT OBJECTIVE: L-ficolin plays an important role in innate immunity and is involved in apoptosis. The objective of this study was to investigate the relationship between serum L-ficolin levels and clinical manifestations in patients with systemic lupus erythematosus (SLE). METHODS: Serum L-ficolin levels were determined by enzyme-linked immunosorbent assay in 66 SLE patients and 50 healthy controls. RESULTS: Median serum L-ficolin levels were 5.0 and 8.7 μg/ml in SLE patients and controls, respectively (p = 0.0001). There were no significant differences in serum L-ficolin levels between the active disease group [SLE Disease Activity Index (SLEDAI) >6] and the inactive disease group (SLEDAI <5). Decreased serum L-ficolin levels were associated with thrombocytopenia (median of with vs. without thrombocytopenia 3.4 vs. 5.3 μg/ml, p = 0.008). There were no correlations between serum L-ficolin levels and SLEDAI, serum C3, or serum C4 levels. CONCLUSION: The association between L-ficolin and thrombocytopenia suggests a pathogenic role for L-ficolin in thrombocytopenia in SLE.