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Background: The role of neopterin as a marker of cell mediated immunity for immunological monitoring after transplantation is of great potential interest. Neopterin levels among hepatitis C virus (HCV) positive recipients of living-donor renal transplantatio (LDRT) have not been previously described. Methods: Twenty-two HCV-positive (group I) and 10 HCV-negative (group II) recipients of LDRT were serially monitored for serum neopterin levels by enzyme-linked immunosorbent assay (ELISA). Group I patients were monitored thrice, ie, before transplantation, day 10, and 6 months post transplantation, while group II patients were monitored twice (day 10 and 6 months post transplantation). Peripheral blood T lymphocyte subsets (CD3, CD4, CD8, CD4+CD25+, CD16+56) and Th1/Th2 cytokines were monitored concomitantly by flow cytometry. Results: Ten days post transplantation, there was a significant increase in neopterin and neopterin/creatnine levels among group I patients. There was a positive correlation between activated T lymphocyte (CD4+CD25+) and neopterin early post transplantation (day 10). Th2 cytokines IL-10 and IL-5 showed a positive correlation with neopterin levels on day 10 and 6 months post transplantation, respectively. Neopterin levels did not show association with either HCV viral load or allograft rejection among our study cohort. Conclusion: Increased monocyte/macrophage activation with elevated serum neopterin was detected among group I patients on day 10 post transplantation, but it could not predict rejection. It appears that IL-10 either from a regulatory or nonregulatory source helps in the maintenance of stable graft early post transplantation. Further, it would be of interest to assess the role of neopterin in chronic allograft nephropathy and long-term graft outcome. [ABSTRACT FROM AUTHOR]

Objective: IL-22 is elevated in patients with inflammatory arthritis and correlates with disease activity. IL-22 deficient mice have reduced incidence of arthritis. Recombinant IL-22 restrains progression of arthritis via increase in IL-10 responses when administered prior to onset of arthritis. These findings imply a possible dual role of IL-22 in inflammatory arthritis depending on the phase of arthritis. Experiments outlined here were designed to elucidate the contribution of endogenous IL-22 before and after the onset of arthritis. Methods: Collagen induced arthritis (CIA) was induced in DBA1 or IFN-γ deficient mice following immunization with collagen and complete Freund's adjuvant. Anti-IL-22 antibody or isotype control were administered prior to or after onset of arthritis and disease progression assessed by clinical scoring and histopathology. IL-22, IL-17 and IFN-γ responses were measured by ELISA and flowcytometry. Anti-collagen antibody responses were analyzed by ELISA. Expression of IL-22R1 in CD4+ cells was elucidated by flowcytometry and real time PCR. Results: Collagen specific IL-22 responses were expanded during arthritis and IL-22 producing cells were discrete from IL-17 or IFN-γ producing cells. Neutralization of IL-22 after onset of arthritis resulted in significant increase in Th1 responses and significantly reduced severity of arthritis. CD4+ cells from arthritic mice showed increased surface expression of IL-22R1. In vitro, CD4+T cells cultured with antigen presenting cells in the presence or absence of IL-22 suppressed or induced IFN-γ, respectively. The protective effect of anti-IL-22 was reversed in IFN-γ deficient mice. Moreover, administration of anti-IL-22 prior to onset of arthritis augmented arthritis severity. Conclusion: We show for the first time that IL-22 plays a dual role: protective prior to the onset of arthritis and pathogenic after onset of arthritis. The pathogenic effect of IL-22 is dependent on suppression of IFN-γ responses. IL-17 responses remained unchanged with the administration of anti-IL22 antibody. IL-22R1 is upregulated on CD4+T cells during arthritis and regulates IFN-γ in T cells. [ABSTRACT FROM AUTHOR]