Immunoglobulin free light chain-kappa, a novel biomarker of inflammation and cardiovascular risk, decreases after smoking cessation in association with NT-proBNP

Abstract Introduction Inflammation plays an important role in the development and progression of cardiovascular diseases. Unhealthy diet, infection, and smoking coupled with genetic factors induce inflammation in the heart and blood vessels by activating nuclear factor kappa B, which regulates the transcription of immunoglobulin free light chain (FLC)-κ in B-cells and the production of multiple inflammatory molecules. FLCs are novel biomarkers of inflammation, and their levels are associated with overall mortality in a general population and with cardiovascular outcomes. Purpose This study aimed to investigate the effect of smoking cessation (SC) on levels of FLCs as well as of the inflammation and heart failure markers. Methods Inclusion criterion was first-visit smokers with desire to quit smoking at our outpatient clinic. Smoking patients with nicotine dependence were treated with transdermal nicotine patches or orally administrated varenicline. Various clinical parameters, including inflammatory markers such as FLC levels, were measured on their first visit to our outpatient clinic for SC and after 3 months of successful and unsuccessful SC. Paired t-test or Wilcoxon signed-rank test was performed to evaluate changes in these parameters before and after SC. Results Out of 96 patients who participated in this study, 76 patients (55 males and 21 females) succeeded in SC over a period of 3 months. Body mass index (BMI) significantly increased from baseline to 3 months after initiating SC (from 23.8 to 24.2, p=0.004) in patients with successful SC. On the other hand, levels of various inflammatory markers; FLC-κ, FLC-κ/FLC-λ, and the neutrophil-to-lymphocyte ratio) significantly decreased from baseline to 3 months (from 27.5 to 24.7 mg/L, p = 0.042; from 1.2 to 1.2 mg/L, p = 0.010; and from 2.0 to 1.9, p = 0.024, respectively). In contrast, no significant changes occurred in these parameters among patients with unsuccessful SC. Percent changes of FLC-κ levels from baseline to 3 months were significantly correlated with those of CRP (r=0.217, p=0.034) and NT-proBNP (r=0.335, p<0.001) levels. Conclusion The FLC-κ level, a novel inflammatory and cardiovascular risk biomarker, decreased in smoking patients after their SC despite the increase in body weight, suggesting that the beneficial effect of SC overcomes potential risks by body weight increase. The results also suggest that a decrease in the FLC-κ level after SC is associated with a reduction of load on the heart as well as decrease in inflammation.