Consistently, in the present study, we explored the immune characteristics in HF using the ssGSEA algorithm, and observed that the abundances of 12 immune infiltrating cells (aDCs, B cells, CD8 + T cells, iDCs, macrophages, mast cells, neutrophils, NK cells, Th1 cells, Th2 cells, TIL, and Treg) and 8 immune-related functions (APC co-inhibition, check-point, cytolytic activity, HLA, inflammation promoting, T cell co-inhibition, T cell co-stimulation, and type I IFN response) were significantly different between HF and NFDs samples. Here, CD8A is linked to hydrops fetalis.