Prevention of TSP-enhanced adhesion of SS RBC to HUVEC by CSA and HDS. RBC suspensions were untreated (control, n = 4), incubated with 1 μg/mL of TSP (n = 3), or sequentially incubated with 200 μg/mL of a given anionic polysaccharide for 30 minutes and then with 1 μg/mL of TSP for 30 minutes. SS RBC adhesion was evaluated as described in Fig 2. At 1 μg/mL, TSP enhanced SS RBC adhesion by ∼50% compared with untreated (None) controls (*P< .01). This enhanced adhesion was prevented by pretreatment with HDS (n = 3) or CSA (n = 3) before TSP (⁺P < .05 to .03, compared with TSP) (pairedt-test). Heparin (n = 3) had a moderate effect (P < .05, compared with TSP) whereas HS (n = 3) and fucoidan (n = 5) had no effect.