Immunoglobulin free light chains and cardiac remodeling in glomerulopathies

Introduction . The role of polyclonal free light chains (pFLC) of immunoglobulins in glomerular diseases is still unknown despite the fact that their elevation predicts a poor prognosis in patients with chronic kidney disease (CKD). One of the possible persuasive mechanisms is the formation of low-grade inflammation which could be the reason for endothelial dysfunction and progression of a cardio-renal continuum. The aim was to estimate the possible association between serum FLC and several parameters of cardiac remodeling in the glomerulopathic patients’ cohort. Materials and methods . We examined 97 patients (51 men and 46 women, average age 48±14,6 years) with biopsy-proven glomerulopathies. We used Freelite (Binding Site Ltd, UK) to measure serum pFLC and other clinical and echocardiographic parameters. We calculated the glomerular filtration rate (eGFR) using the 2021 CKD-EPI Creatinine equation. We also performed echocardiography to measure some parameters of cardiac chamber remodeling. Results. Mean eGFR was 46.8 ml/min/1.73 m2 (28.7–80.0), the FLC-kappa level was 27.4 mg/l (16.8–48.4), the FLC-lambda level was 28.2 mg/l (20.8–43.3). The reference levels of FLC in the group were exceeded in 65 % for FLC-kappa and in 54% for FLC-lambda patients. A nonparametric Mann–Whitney U-test was performed to compare the effect of pFLC levels on the parameters of LV and LA geometry. If levels of FLC-kappa were higher than 19,4 mg/l, the left ventricular myocardium mass index (LVMMI) was statistically significantly bigger (99,9±31,2 g/m2 versus 138,3±30,2 g/m2 , р=0,022). If levels of FLC-lambda were higher than 26,3 mg/l, LVMMI was also bigger (104,0±36,6 g/m2 versus 136,2±64,8 g/m2, р=0,023). The left atrium (LA) volume index was also statistically significantly bigger at higher levels of FLC-lambda (33,8±8,0 ml/m2 versus 40,3±11,6 ml/m2, р=0,031). The Spearman analysis has shown statistically significant correlations between FLC levels, LVMMI and LA volume index. Conclusion. The serum pFLC level reflects the grade of local tissue immune inflammation and endothelial dysfunction. The obtained data indicate the involvement of pFLC in cardiac remodeling mechanisms as one of the important stages in the cardiorenal continuum in all types of glomerulopathies.