CRP and systemic lupus erythematosus: As the concentration of FLCs correlated with global disease activity scores, reflected inflammation (high CRP and complement consumption) and B cell activity (high dsDNA antibody titers and total IgG and total IgA concentrations) in the SLE patients, the results obtained in this study suggest that the easily quantified FLC concentrations in the circulation could be a supplementary serologic biomarker in SLE.