Immunoglobulin free light chains as an inflammatory biomarker of heart failure with myocarditis.

Abstract Background In this study, we measured immunoglobulin free light chains (FLC), a biomarker of inflammation in the sera of patients with heart failure due to myocarditis. Methods FLC kappa and FLC lambda were assayed in stored serum samples from patients with heart failure with myocarditis from the US myocarditis treatment trial by a competitive-inhibition multiplex Luminex® assay. Results The median concentration of circulating FLC kappa/lambda ratio was significantly lower in the sera from patients with heart failure with myocarditis than in healthy controls, and FLC kappa/lambda ratio had good diagnostic ability for identification of heart failure with myocarditis. Further, FLC kappa/lambda ratio was an independent prognostic factor for overall survival, and allowed creation of three prognostic groups by combining with N-terminal pro-B-type natriuretic peptide. Conclusions This study suggests that FLC kappa/lambda ratio is a promising biomarker of heart failure with myocarditis.