MBL2 and atrial fibrillation: In particular, the main goals were to quantify the concentration of MBL, Ficolin 2, and Ficolin 3 in AF and subsequently, after in vitro infection with carbapenem-resistant Enterobacterales, as E. coli-CR and KPC-Kp strains, to monitor the trend of the concentrations of the same proteins over time in the presence (or not) of hA-MSCs.