Moreover, HBV induces immune-suppressive cells, such as myeloid-derived suppressor cells (MDSCs), NK-regs, and T-regs, to form an immunosuppressive cascade through inhibitory molecules, such as PD-L1, programmed cell death protein 1 (PD-1), and IL-10, which contributes to persistent HBV infection and the progression of HF [37]. This evidence concerns the gene PDCD1 and hydrops fetalis.