Serum‐free light chains as a dependable biomarker for stratifying patients with metabolic dysfunction‐associated steatotic liver disease.

Background and Aims: Adaptive immunity is gaining a significant role in progression of metabolic dysfunction‐associated steatotic liver disease (MASLD). B‐cell activity can be assessed by serum‐free light chains (sFLCs) k and λ levels. The objective of the present investigation is to examine the utility of sFLCs as non‐invasive biomarkers for the stratification of MASLD. Methods: We enrolled a consecutive cohort from an outpatient liver unit. Diagnosis of metabolic dysfunction‐associated steatohepatitis (MASH) was made with liver biopsy according to current guidelines. Compensated advanced chronic liver disease (cACLD) and clinically significant portal hypertension (CSPH) were defined according to Baveno VII criteria. sFLCs were measured by turbidimetry using an immunoassay. Results: We evaluated 254 patients, 162/254 (63.8%) were male. Median age was 54 years old, and the median body mass index was 28.4 kg/m2. A total of 157/254 (61.8%) subjects underwent liver biopsy: 88 had histological diagnosis of MASH, 89 were considered as simple metabolic dysfunction‐associated steatotic liver (MASL) and 77/254 (30.3%) patients with compensated metabolic dysfunction‐associated cirrhosis. By using Baveno VII criteria, 101/254 (39.7%) patients had cACLD; among them, 45/101 (44.5%) had CSPH. Patients with cACLD showed higher sFLC levels compared with patients without cACLD (p <.01), and patients with CSPH showed higher sFLC levels than patients without CSPH (p <.01). At multivariable analysis, sFLCs were associated with cACLD (p <.05) independently from γ‐globulins and other known dysmetabolic risk factors. κFLC was associated with CSPH (p <.05) independently from γ‐globulins and other known dysmetabolic risk factors. Conclusion: sFLCs could be a simple biomarker for stratification of cACLD in MASLD patients. [ABSTRACT FROM AUTHOR]