CCR4 and systemic lupus erythematosus: In addition, the expression profile of chemokine receptors on Vδ2 T cells was examined, and we found that the CCR4, CCR7, CCR8, CXCR1, CX3CR1, and CD40 L expression levels as well as IL-21 secretion by Vδ2 T cells were significantly elevated in SLE patients and were downregulated after treatment with corticosteroids and immunosuppressants.