Studies with IL-2 + bevacizumab (one study, 100%) and IL-2 + IFN-alpha 2a (two studies, overall estimation 85.5%, meta-analysis 90.4%) showed relatively high CLS incidence proportions, while studies with gemcitabine (three studies, overall estimation 3.5%, meta-analysis 4.9%) and GM-CSF (three studies, overall estimation 9.0%, meta-analysis 10.1%) showed low incidence. Here, IL2 is linked to capillary leak syndrome.