TNF and periodontitis: For immune pathways, the most positively correlated pair is CXCR4-BCR Signaling Pathway, and a higher expression of CXCR4 and more BCR Signaling Pathway reaction were found in periodontitis (Figure 4C); while the most negatively correlated pair is PEX3-TNF Family Members Receptors and a lower expression of PEX3 and more active TNF Family Members Receptors reaction were found in periodontitis (Figure 4D).