IL21 and glioblastoma: Furthermore, our immunological data suggests that immune cells from patients with malignant primary glioma (i.e. GBM) can strongly recognize and respond to cell surface-bound, mature mesothelin (GPI-anchored component) via cytokine production (IFN-γ, TNF-α), as well as antibody (IgG) production T cells from patients with GBM are able to expand dramatically in the presence of conditioning medium containing IL-2/IL-15/IL-21 as well as the mesothelin peptide pool - for antigen-specific cell activation.