C4A and hydrops fetalis: Figure 4B shows the GSVA scores of HF.Sig in different B cell C4 subclusters in the disease and normal groups in different cells. These genes were enriched in patients (Figure 4C) and had significantly higher GSVA scores (Figure 4D). The gene sets were composed of B cell C4 cluster markers, and 115 genes were obtained from these gene sets. ROC curves for the 115 genes demonstrated a significant predictive power of the gene signature for the development of HF after MI, AUC = 0.9 (95% CI: 0.86–0.94. p = 0.0034) (Figure 5A).