Failure of in vitro T‐cell assays to predict clinical outcome after human kidney transplantation

Abstract

Allotransplant rejection is a T-cell-dependent reaction. Functional in vitro T-cell assays are being used widely for donor-recipient matching in bone marrow transplantation and have recently been used in some centres for transplant monitoring. In order to assess tolerance induction after clinical transplantation, we measured the T-cell response of the host against donor spleen cells of 33 kidney transplant patients before and every 3 months after transplantation over a period of 18 months. The T-cell reactivity before transplantation was not significantly different in any of the assays in rejecting and non-rejecting patients. In the classical mixed lymphocyte culture (MLC), a donor-specific loss of reactivity was seen only in a patient with a CMV-associated irreversible transplant rejection. One patient with chronic rejection acquired a very high MLC response against donor spleen cells and a high response against third-party cells. Little or nonspecific changes were seen in the MLCs of all other patients. Using the method of limiting dilution analysis (LDA), we found a significant reduction of donor-specific cytotoxic T-cell precursors (CTL-p) within the first 3 months after transplantation in most patients with high antidonor CTL-p frequencies before transplantation. The reduction of donor-specific CTL-p was seen in patients with rejection episodes as well as in patients without. Thus we conclude, in contrast to others, that MLC and CTL-p LDA have no predictive value on the outcome of clinical transplantation.

Relevance of regulatory T cell promotion of donor-specific tolerance in solid organ transplantation

“…Monitoring of donor-reactive immune responses has demonstrated that hyporesponsiveness to the direct pathway can develop shortly after solid organ transplantation and is in general associated with stable graft function (Hornick et al, 1998; De Haan et al, 2000). Donor-specific cytotoxic or T cell hyporesponsiveness has been detected in kidney (Ghobrial et al, 1994; Mason et al, 1996; Mestre et al, 1996; Hornick et al, 1998; Baker et al, 2001b), heart (Hu et al, 1994; Hornick et al, 2000; Van Hoffen et al, 2000) and lung (De Haan et al, 2000) transplantation, although this is not a universal finding (Eberspacher et al, 1994; Loonen et al, 1994; Steinmann et al, 1994; Oei et al, 2000). In addition, hyporesponsivessness to donor antigen presented by the indirect pathway has also been described (Salama et al, 2003b).…”

Immunodominance Hierarchies and Gender Bias in Direct TCD8-Cell Alloreactivity

“…Historically, the CTLp assay was used to quantitate the precursor frequency of allospecific T cells that could potentially expand and induce an alloresponse. The value of this assay has been controversial with opposing perspectives on the predictive power of the assay and clinical outcome (18)(19)(20)(21)(22)(23)(24)(25). Therefore we assessed the correlation between CTLp (LDA-based) and the proportion of T CD8+ cells with allospecificity after 13 days culture in vitro and measured in the MLR-ICS assay.…”

“…Quantitation of allospecific T-cell precursors, using limiting dilution based assays (LDA; cytotoxic T lymphocyte precursor [CTLp] and helper T lymphocyte precursor) (8,9), have all been used to assess the in vitro allogeneic potential of HLA mismatches (10)(11)(12)(13)(14)(15)(16)(17). However, the correlation between the quantitation of allospecific T-cell precursor frequencies and incidences of graft rejection or GvHD has been disappointing and laboratory-dependent (18)(19)(20)(21)(22)(23)(24)(25). Indeed, limitations of LDA based applications have been highlighted through enumeration of antigen-specific T cells in both human (26)(27)(28) and murine models (29).…”

Immunological Monitoring of Renal Transplant Recipients to Predict Acute Allograft Rejection Following the Discontinuation of Tacrolimus

“…In bone marrow transplantation, high CTLp frequencies were associated with prolonged leukemia free survival time [12]. However, the benefit of CTLp assessment in solid organ transplantation remains controversial [13], [14]. Using Elispot assays, low numbers of donor-specific IFN-γ producing T cells were associated with stable long-term renal function [15], [16].…”