Strong correlations were found between PD1 (PDCD1) and PD-L1 (CD274)/PD-L2 (PDCD1LG2), between CTLA4 and CD80/CD86, and between CXCR4 and CXCL12 (Fig. 5C) in PAs. Here, CXCR4 is linked to gonorrhea.