PPBP and neurosyphilis: There was no significant difference in serum CCL24 levels between groups (1079 ± 165.2 pg/mL vs 1641 ± 356.2 pg/mL, P = .2830; Figure 2B); however, serum CXCL7 levels were lower in patients with than without neurosyphilis (5.511 ± 0.4946 ng/mL vs 6.741 ± 0.4094 ng/mL, P = .0004; Figure 2D).