Regulatory/inflammatory cellular response discrimination in operational tolerance

Abstract

Background. Antigen-specific cellular response is essential in immune tolerance. We tested whether antigen-specific cellular response is differentially modulated in operational tolerance (OT) in renal transplantation with respect to critical antigenic challenges in allotransplantation—donor antigens, pathogenic antigens and self-antigens. Methods. We analysed the profile of immunoregulatory (REG) and pro-inflammatory (INFLAMMA) cytokines for the anti gen-specific response directed to these three antigen groups, by Luminex. Results. We showed that, in contrast to chronic rejection and healthy individuals, OT gives rise to an immunoregulatory devi ation in the cellular response to donor human leucocyte antigen DR isotype peptides, while preserving the pro-inflammatory re sponse to pathogenic peptides. Cellular autoreactivity to the N6 heat shock protein 60 (Hsp60) peptide also showed a REG pro- file in OT, increasing IL4, IL-5, IL-10 and IL-13. Conclusions. The REG shift of donor indirect alloreactivity in OT, with inhibition of interleukin (IL)-1B, IL-8, IL-12, IL-17, granulocyte colony-stimulating factor, Interferon-c and mono cyte chemoattractant protein-1, indicates that this may be an important mechanism in OT. In addition, the differential REG profile of cellular response to the Hsp60 peptide in OT suggests that REG autoimmunity may also play a role in human trans plantation tolerance. Despite cross-reactivity of antigen-specific T cell responses, a systemic functional antigen-specific discrimi nation takes place in OT.