We used ssGSEA to analyze the levels of immune cell infiltration between HC and HF groups and found that activated CD4 T cells, CD56bright natural killer cells, CD56dim natural killer cells, eosinophils, macrophages, mast cells, neutrophils, and type 17 T helper (Th17) cells showed significant differences in infiltration between groups (Figure 3A). Here, CD4 is linked to hydrops fetalis.