The key targets of the IL-17 signaling pathway include NF-κB, AP-1, IL-6, IL-1β, TNFα, IFN-γ, CCL2, COX2, MMP1, MMP3, and MMP9, which all exert vital parts in HF development (Tan et al., 2020; Zhou et al., 2020). Here, MMP9 is linked to hydrops fetalis.