Immunoglobulin free light chains: an inflammatory biomarker of diabetes.

Inflammation is increasingly understood as playing an important role in type 2 diabetes mellitus (T2D) development. A critical mechanism of the inflammatory cascade in developing T2D is nuclear factor-kappa B (NF-kB) activation. As immunoglobulin free light chains (FLC) could be a biomarker of activation of NF-kB, we measured FLC in patients with T2D. The age range of the 77 patients with T2D and the 75 healthy control participants were 45-87 years (median 60) and 25-72 years (median 51), respectively. Serum FLC kappa and lambda were assayed by a competitive-inhibition multiplex Luminex assay. The concentration of circulating FLC the kappa/lambda ratio was lower in patients with T2D than in healthy volunteers. The area under the receiver operating curve (ROC-AUC) of the FLC kappa/lambda ratio showed the largest ROC-AUC compared with other FLC variables and hemoglobin A1c (HbA1c). The diagnostic performance for distinguishing between T2D and healthy control was a sensitivity of 0.96 and a specificity of 1. The odds ratio was 0.000018. These results suggest that FLC kappa/lambda may be more specific and sensitive for the diagnosis of T2D than HbA1c, and thus represents a potentially promising biomarker of inflammation.