Figure 3.

Immune phenotype of vaccine-induced immune thrombotic thrombocytopenia patients. Analysis of 5 cases and 12 vaccinated healthy control blood samples at three time points. (A) Peripheral blood of healthy donors and cryo-preserved PBMC from vaccine-induced immune thrombotic thrombocytopenia patients were surface stained to characterize low-density neutrophils. After the removal of debris and dead cells based on FSC-A and SSC-A, singlets were gated for haematopoietic cells. Granulocytes were defined as CD45⁺SSC^HiCD66b⁺CCR3⁻CD123⁻ (see also Supplementary material online, Figure S2 for gating). (B) Longitudinal follow-up of neutrophils in surviving vaccine-induced immune thrombotic thrombocytopenia patients. The expression of maturation markers on neutrophils was compared between healthy donors (HD, top panel) and fatal vaccine-induced immune thrombotic thrombocytopenia (Patients 2 and 5, top) or in longitudinal samples for non-fatal cases (Cases 3 and 4 at Day 7, Day 14 or 20 for Time-points 2 and 3, respectively). The intensity of each marker was normalized in the overlaid histograms. See also Supplementary material online, Figure S4 for hierarchical clustering of all time points.