Pro-inflammatory cytokines associate with NETosis during sickle cell vaso-occlusive crises.

•Sickle cell environment remains highly pro-inflammatory even during hydroxyurea treatment.•Numerous pro-inflammatory cytokine levels remain elevated at steady state and crises.•Plasma from SCD patients in VOC whilst on hydroxyurea treatment, can trigger NETs formation.•Increased NETs production at crises appears to correlate with increased levels of IL-6 and IL-1ra.