Free light chains in patients with acute coronary syndromes: relationships to inflammation and renal function

Aims We assessed changes of serum combined free immunoglobulin light chains (cFLC) levels, which are associated with increased all-cause mortality, in ST-elevation myocardial infarction (STEMI) in relation to inflammation and renal function indices. Methods cFLC were measured in 48 patients with STEMI on days 1, 3, 7 and 30 with assessment of their relationships with monocyte subsets, high sensitivity C-reactive protein (hsCRP), and cystatin C. Day 1 levels in STEMI patients were compared to 40 patients with stable coronary artery disease, and 37 healthy controls. Results There were no significant differences in cFLC levels between the study groups. In STEMI patients, cFLC values peaked on day 7 post-MI and remained elevated on day 30 (p < 0.001 vs. day 1 for both). hsCRP concentrations peaked on day 3 of STEMI followed by their gradual reduction to the levels seen in the controls (p < 0.001). In STEMI cFLC correlated with cystatin C (r = 0.55, p < 0.001), and negatively correlated with counts of CD14++CD16– monocytes (r = -0.55, p < 0.001). On multivariate Cox regression analysis, cFLC concentrations were associated with increased need for future percutaneous coronary intervention (PCI) (p = 0.019). Conclusion cFLC levels increase during STEMI with peak values on day 7 after presentation and predict the need for future PCI.