Analysis of lymphocytes reactive to histocompatibility antigens. III. Detection of inclusion among allo-reactive lymphocyte populations by specific depletion of reactive cells

Donor-Reactive Regulatory T Cell Frequency Increases During Acute Cellular Rejection of Lung Allografts

BACKGROUND

Acute cellular rejection is a major cause of morbidity after lung transplantation. Because regulatory T (Treg) cells limit rejection of solid organs, we hypothesized that donor-reactive Treg increase after transplantation with development of partial tolerance and decrease relative to conventional CD4 (Tconv) and CD8 T cells during acute cellular rejection.

METHODS

To test these hypotheses, we prospectively collected 177 peripheral blood mononuclear cell specimens from 39 lung transplant recipients at the time of transplantation and during bronchoscopic assessments for acute cellular rejection. We quantified the proportion of Treg, CD4 Tconv, and CD8 T cells proliferating in response to donor-derived, stimulated B cells. We used generalized estimating equation-adjusted regression to compare donor-reactive T cell frequencies with acute cellular rejection pathology.

RESULTS

An average of 16.5 ± 9.0% of pretransplantation peripheral blood mononuclear cell Treg cell were donor-reactive, compared with 3.8% ± 2.9% of CD4 Tconv and 3.4 ± 2.6% of CD8 T cells. These values were largely unchanged after transplantation. Donor-reactive CD4 Tconv and CD8 T cell frequencies both increased 1.5-fold (95% confidence interval [95% CI], 1.3-1.6; P < 0.001 and 95% CI, 1.2-1.6; P = 0.007, respectively) during grade A2 rejection compared with no rejection. Surprisingly, donor-reactive Treg frequencies increased by 1.7-fold (95% CI, 1.4-1.8; P < 0.001).

CONCLUSIONS

Contrary to prediction, overall proportions of donor-reactive Treg cells are similar before and after transplantation and increase during grade A2 rejection. This suggests how A2 rejection can be self-limiting. The observed increases over high baseline proportions in donor-reactive Treg were insufficient to prevent acute lung allograft rejection.

Genetic control of cell-mediated immunity in the rat. I. Transfer of DTH to bacterial antigens is restricted by the B region of RT1

The genetic basis of allogeneic restriction in the transfer of delayed type hypersensitivity (DTH) to soluble Listeria monocytogenes antigens (LMA) in rats was analysed using a set of congenic strains. The DTH parameter assayed was the localization of radiolabelled donor lymphoblasts in subcutaneous antigen stimulation sites in the ear. Sharing of the RT1,B region between the donor and host was essential for the transfer of DTH to LMA, which suggests that the RT12.B region codes for restriction elements controlling antigen recognition by TDTH cells. The recombinant haplotype RT1 rl was exceptional in that transfer of DTH to A-region matched recipients was, at least in part, possible, Measurement of donor lymphoblast localization in DTH sites afforded an opportunity to quantify allogeneic effects influencing localization of sensitized donor cells in DTH sites borne by alien recipients. Both RT1.B and RT1.A region differences could induce allogeneic effects, but they were an order of magnitude lower than those based on restricted recognition by donor T cells.