IL21 and systemic lupus erythematosus: As these cells exhibited a decreased apoptosis rate, an increased proliferation rate, and upregulated levels of costimulatory factors including CD40L and IL-21, we suggest that these overgrown and hyperactive inflammatory Vδ2 T cells are increasingly recruited to tissues via the upregulation of a variety of chemokine receptors to participate in inflammation and tissue damage in SLE.