IL6 and capillary leak syndrome: Regarding possible triggers, lymphoma-complicated CLS patients have elevated levels of various cytokines, such as granulocyte colony-stimulating factor (G-CSF), interleukin-6 (IL-6), interleukin-10 (IL-10), interferon-gamma (IFN-γ) and tumor necrosis factor alpha (TNF-α) (7, 10–12).