Combining with Lasso and RF models, we then obtained a total of 14 key immune cell types with HF (activated CD4+ T cell, activated CD8+ T cell, activated dendritic cell, CD56dim natural killer cell, MDSC, macrophage, natural killer T cell, natural killer cell, neutrophil, Type 17 T helper cell, Type 2 T helper cell, effector memory CD4+ T cell, memory B cell, and central memory CD8+ T cell). This evidence concerns the gene CD4 and hydrops fetalis.