Pattern of cytokine expression in circulation CD57⁺ T cells from long-term renal allograft recipients

We made a quantitative analysis of the lymphokine mRNA and of proteins produced by CD57⁺ and CD57^- circulating T cells isolated from long-term kidney-transplanted patients with expanded CD4⁺/CD57⁺ and CD8⁺/CD57⁺ T cells, and from normal individuals. We concentrated on IL-2 and IFN-γ, which define a Th1-like type of lymphokine production, and on IL-4 which defines a Th-2-like type. We also analysed the production of IL-10 which is endowed with inhibitory effects on IL-2 and IFN-γ synthesis, and of TNF-α, a pleiotropic inflammatory cytokine. On ionomycin + PMA stimulation, which reveals the intrinsic potential of lymphokine production by T cells, the CD57⁺ T cell subsets from all individuals produced high amounts of IFN-γ and TNF-α mRNA and protein. They also produced IL-2, but to a much lesser extend than their CD57^- counterparts, and little IL-4 and IL-10. They were no more capable of producing IL-2 when stimulated through the CD3/TCR in the presence of monocytes, yet still synthesized IFN-γ. Our data suggest that the in vivo expansion of CD57⁺ T cells in stable allograft renal recipients might correspond to Th1 energized cells which on triggering of cell surface receptors hardly secrete lymphokines involved in cell cycle progression, but can still exert some effector functions, including IFN-γ secretion.