T-Rapa Cell DLI Safely Balances Th1/Th2 Cytokine Activation After Low-Intensity Allogeneic Hematopoietic Cell Transplantation (2011)

We recently reported that pre-emptive DLI with donor T-rapa cells safely promotes alloengraftment after low-intensity allogeneic HCT (ASH, 2010; multi-center clinical trial NCT0074490). T-rapa cells were manufactured ex vivo using purified CD4+ T cells, rapamycin, co-stimulation, and IL-4. T-rapa clinical products contained minimal Treg cells and secreted both Th1 (IFN-γ, IL-2) and Th2 cytokines (IL-4, IL-5, IL-10, and IL-13). On one protocol arm, refractory hematologic malignancy patients (n = 40) received EPOCH-FR induction chemotherapy, low-dose fludarabine/cyclophosphamide (Cy) preparative chemotherapy (total Cy dose, 1200 mg/m2), T cell-replete mobilized allografts, and GVHD prophylaxis of cyclosporine and short-course sirolimus (until day +14 post-HCT). T-rapa cells were administered at day +14 (2.5 × 107 T-rapa cells/kg). This transplant approach was safe, as there was: (1) no engraftment syndrome (0/40 cases); (2) a low rate of grade II-IV acute GVHD (4/40); and (3) no transplant-related mortality (0/40). Complete remission has been sustained in 37.5% (15/40) of patients. Median survival is 28.5 months; 24-month survival probability is 64.4%. T-rapa DLI was associated with conversion of mixed chimerism: median donor CD3+ T cell chimerism values at days +14, +28, and +100 were 61%, 89%, and 93%, respectively. The capacity of T-rapa DLI to safely promote alloengraftment suggested that a balanced pattern of Th1/Th2-type cytokines may have been activated post-HCT. To assess this, post-HCT peripheral blood T cells were co-stimulated; supernatants were then tested for cytokine content.Table 1Day +14 Post-HCT DLI With T-rapa Cells Yields Balanced type I/type II Cytokine SecretionT Cell SupernatantPrior to T-rapa InfusionAfter T-rapa InfusionDay +7Day +14Day +28Day +50IFN-γ957 ± 487246 ± 114976 ± 7221165 ± 550IL-22058 ± 1334124 ± 291601 ± 1093706 ± 214TNF-α7617 ± 6475310 ± 112413 ± 204438 ± 118IL-1733 ± 1< 1108 ± 10842 ± 36IL-44 ± 42 ± 220 ± 158 ± 5IL-5105 ± 102 ± 1157 ± 103100 ± 57IL-105 ± 27 ± 124 ± 1218 ± 7IL-1322 ± 1514 ± 7218 ± 145167 ± 57Ex vivo generated donor T-rapa cells were administered as a pre-emptive DLI at day +14 post-HCT. Post-HCT mononuclear cells were harvested at days +7, +14, +28 (± 2 days) and day +50 (± 4 days) post-HCT; cells were subjected to CD3, CD28 co-stimulation, and 24 h supernatants were tested for cytokine content by multi-plex assay. Values shown are mean ± SEM, in pg/ml. For each measurement, values were available on n = 29 to n = 30 T-rapa cell recipients. Open table in a new tab Day +7 T cells secreted large quantities (ng/ml range) of Th1 cytokines IFN-γ and IL-2; Th1 cytokine secretion was blunted by day +14 but increased again after T-rapa DLI. TNF-α secretion was prominent at day +7, normalized prior to T-rapa DLI, and was not increased post-DLI. IL-17 was undetectable at day +14 and was moderately increased after T-rapa DLI. Early post-HCT, Th2 cytokine secretion was modest, particularly at day +14; mean values for IL-4, IL-5, and IL-13 secretion were increased by at least one-log at day +28 and were generally increased at day +50. Mean values for IL-10 were modestly higher after T-rapa DLI. In conclusion, pre-emptive DLI with T-rapa cells was associated with a balanced activation of both Th1- and Th2-type cytokines that appears favorable for the safe promotion of alloengraftment after low-intensity host preparation. Ex vivo generated donor T-rapa cells were administered as a pre-emptive DLI at day +14 post-HCT. Post-HCT mononuclear cells were harvested at days +7, +14, +28 (± 2 days) and day +50 (± 4 days) post-HCT; cells were subjected to CD3, CD28 co-stimulation, and 24 h supernatants were tested for cytokine content by multi-plex assay. Values shown are mean ± SEM, in pg/ml. For each measurement, values were available on n = 29 to n = 30 T-rapa cell recipients.