Elevated monocyte adhesion in SCD. (A-B) Monocyte-adhesion after 1 hour with 1 μM S1P, AA plasma, or SS plasma treatment of AA PBMCs. Representative fluorescent images showing adherent DRAQ5 labeled THP-1 cells after 4 hours of adhesion to HUVECs (B). (C-D) RBCs co-incubated with THP-1 monocytes (10:1) for 18 hours. Representative confocal images (C) and monocyte:HUVEC ratio after 4-hour adhesion (D). *P < .05 measured with 1-way ANOVA or Student t test relative to vehicle or AA.