Fig. 5

Low erythrocytic BgA-expression levels affects rosetting rate when exposed to rosette-disruptive agents. Rosetting rate of FCR3S1.2 parasites grown in RBCs from 30 donors per blood group (O, A1 negative, A1 positive, B and AB) was measured by flow cytometry in three conditions; A, B untreated, C, D heparin 50 µg/mL and E, F anti-PfEMP1-DBL1ɑ treated (250 µg/mL). Relative A antigen levels were determined by flow cytometry as relative mean fluorescent intensity (MFI) after immunofluorescent staining of RBCs. Correlation between A-antigen levels and rosetting rate was assessed using Spearman’s rank correlation coefficient for each condition (right panels). Pairwise comparison of BgO and all non-O Bgs performed using unpaired t-test with Holm adjustment of P-values (* P ≤ 0.05; ** P ≤ 0.01; *** P ≤ 0.001). All box plots display median values (middle line) and the lower and upper quartile values form the box, with whiskers extending to one and a half times the interquartile range