CD4−veCD8−ve CD30+ve T Cells Are Detectable in Human Lung Transplant Patients and Their Proportion of the Lymphocyte Population After In Vitro Stimulation With Donor Spleen Cells Correlates With Preservation of Lung Physiology

IntroductionSurvival following lung transplantation is less than 50% at 5 years, mainly due to immune-mediated chronic rejection. Recently a novel subset of T cells, CD4−veCD8−ve CD30+ve, so-called double negative (DN) CD30+ve T cells, has been described and shown to be responsible for tolerance in an animal model of skin transplantation.MethodsWe investigated 18 lung transplant recipients for the presence of DN CD30+ve T cells in resting peripheral blood and also following in vitro stimulation of recipient peripheral blood mononuclear cells (PBMCs) with donor spleen cells.ResultsSmall percentages (0.2% to 6%) of DN T cells are detectable in resting PBMCs of human transplant patients (n = 18), but these did not correlate with allograft function, acute rejection episodes, HLA mismatch, or CMV status. On repeated stimulation of recipient PBMCs (two exposures) in vitro by donor spleen cells (2:1 ratio stimulators to responders) the percentage of DN CD30+ve T cells within the lymphocyte pool correlated with preservation of allograft lung function (both for FEV1, P = .009, and FEF25–75, P = .036) and was inversely correlated with grade of chronic rejection. On repeated exposure of recipient PBMCs to donor spleen cells with a 1:1 ratio the percentage of DN CD30+ve T cells correlated with the number of acute rejection episodes of grade 2 or greater. The total number of HLA mismatches correlated with the percentage DN CD30+ve T cells present after primary stimulation of recipient PBMCs with donor spleen cells (1:1 ratio). The number of mismatches at the B locus inversely correlated with the percentage of DN CD30+ve T cells after primary stimulation of recipient PBMCs with donor spleen cells (1:1 ratio; P = .031, n = 18).ConclusionPercentages of DN CD30+ve T cells present following repeated stimulation of recipient PBMCs by donor spleen cells correlated with preservation of graft function following lung transplantation.