From previous studies showing that ICOS and ICOSL upregulation in human leucocytes correlated with an increase in the circulating levels of their respective soluble forms (25) we evaluated soluble ICOS (sICOS) and ICOSL (sICOSL) in the sera of patients with histologically proven MASLD/MASH. Here, ICOS is linked to metabolic dysfunction-associated steatotic liver disease.