Flow cytometry assessment of graft-infiltrating lymphocytes can accurately identify acute rejection in kidney transplants.

BACKGROUND: Previously, we have reported that flow cytometry analysis of fine-needle aspirates can accurately predict rejection in kidney transplants treated with cyclosporine-azathioprine-prednisolone. In this study, we examined this technique's accuracy using current immunosuppression. METHODS: Kidney transplant recipients were treated with calcineurin inhibitors, mycophenolate mofetil, and prednisolone: 92 remained rejection-free - Group I - and 37 developed acute rejection - Group II. An allograft aspiration specimen and peripheral blood were collected from Group I on post-transplant day 7 and from Group II on the day of clinical rejection. RESULTS: Significant changes were seen in both aspiration and peripheral blood samples in several T cell subsets when comparing Groups I and II. A sensitivity of 94.6%, specificity of 85%, and AUC = 0.966 were observed through combining CD8DR with CD3CD69 values from aspiration specimen; the corresponding AUC in peripheral blood was 0.847. Irreversible rejections displayed a significantly higher activation score (p = 0.024). CONCLUSIONS: Flow cytometry analysis of aspiration specimen achieved high diagnostic performance in renal transplants through studying CD8DR and CD3CD69 under current immunosuppressive therapy. Peripheral blood analysis, although not significant, showed the same trend. The activation score anticipated the irreversibility of rejection. The data suggest this test, through an easily tolerated technique, merits further diagnostic use.

Compared to mycophenolate mofetil, rapamycin induces significant changes on growth factors and growth factor receptors in the early days post-kidney transplantation.

BACKGROUND: The new immunosuppressive drug Rapamycin (Rapa) is endowed with a mechanism of action that is distinct from that of calcineurin inhibitors. It has been claimed that Rapa does not significantly modulate either the cytokine expression or the transcription of several growth factors in mitogen-activated T cells. Previously, we reported that fine-needle aspiration biopsy (FNAB) sample cultures synthesize a large array of cytokines, and some of them may be powerful predictors of acute rejection in renal transplants. We hypothesized that Rapa may induce significant changes on cytokine production by FNAB sample cultures and on serum cytokine receptors when compared to other immunosuppressive drugs. METHODS: Kidney transplants treated with CsA-Rapa-Pred (Rapa group) were compared with transplants treated with CsA-mycophenolate mofetil-Pred (MMF group). They were studied on day 7 posttransplantation, and they remained rejection free for at least the first 6 months. FNAB samples were cultured and the supernatants were collected at 48 hr of incubation and analyzed by ELISA for interleukin 1 receptor antagonist (IL-1ra), IL-2, IL-6, IL-10, IL-18, monocyte chemotactic protein 1 (MCP-1), soluble tumor necrosis factor I, and transforming growth factor (TGF)-beta(1). The soluble receptors for IL-1, IL-2, IL-6, and tumor necrosis factor alpha, together with IL-2 and IL-18 were also measured in serum. RESULTS: Significant differences were observed when comparing Rapa with the MMF group. IL-18 and TGF-beta(1) synthesis were up-regulated, whereas IL-6 and MCP-1 were down-regulated in FNAB sample cultures. The Rapa group showed a significant down-regulation of each cytokine receptor and of IL-2 in serum. CONCLUSIONS: Rapa was associated with a decreased synthesis of primarily monocyte-derived cytokines and enhanced production of TGF-beta(1), which in an appropriate cytokine milieu may promote allograft tolerance. The down-regulation of cytokine receptors and IL-2 may be associated with a depressed immune response towards the kidney allograft.