Graft-versus-host disease can be separated from graft-versus-lymphoma effects by control of lymphocyte trafficking with FTY720

Abstract

Graft-versus-host disease (GvHD) mediated by donor T cells recognizing host alloantigens is associated with beneficial graft-versus-tumor effects in recipients of allogeneic hematopoietic cell transplants. Since leukemias and lymphomas reside largely within the lymphohematopoietic system, we have proposed that the desired graft-versus-leukemia or graft-versus-lymphoma effect can be separated from the complication of GvHD by confinement of the graft-versus-host alloresponse to the lymphohematopoietic tissues. Since the new sphingosine-1-phosphate receptor agonist immunosuppressive drug FTY720 leads to trapping of T cells in secondary lymphoid tissues, we evaluated the possibility that this drug could diminish GvHD, a disease involving epithelial target tissues, while permitting a beneficial alloresponse to take place within the lymphohematopoietic system, leading to graft-versus-lymphoma effects. We demonstrate here that FTY720 markedly reduces GvHD in a clinically relevant, haploidentical strain combination, while permitting antitumor effects against a T cell lymphoma of unshared host MHC haplotype to proceed unhindered. These results establish a potential new immunotherapeutic approach to separating graft-versus-leukemia effects from GvHD.

Figure 1

FTY decreases GvHD mortality and inhibits GvHD-associated weight loss. (a) GvHD mortality. (b and c) Weight curves of the syngeneic groups (b) and allogeneic groups (c). Lethally irradiated B6D2F1 mice received haplotype-mismatched GvHD-inducing C3D2F1 BMCs (5 × 10⁶) and spleen cells (1 × 10⁶), as well as daily treatment, by oral gavage on days 0–29 post-BMT, with either H₂O (filled inverted triangles; n = 10) or FTY at a dose of 3 mg/kg (filled circles; n = 10), 1 mg/kg (filled squares; n = 10), or 0.1 mg/kg (filled diamonds; n = 10). Syngeneic control groups received 5 × 10⁶ B6D2F1 BMCs and either H₂O (open inverted triangles; n = 5) or different doses of FTY (3 mg/kg, open circles, n = 5; 1 mg/kg, open squares, n = 5; or 0.1 mg/kg, open diamonds, n = 5). *Statistically significant difference compared with H₂O-treated control group (P < 0.05).

Figure 2

FTY inhibits GvHD induced by a rapidly lethal dose of allogeneic spleen cells. (a) GvHD mortality. (b and c) Weight curves of the syngeneic (b) and allogeneic (c) groups. Lethally irradiated B6D2F1 mice received haplotype-mismatched C3D2F1 BMCs (5 × 10⁶) and an increased dose of spleen cells (3 × 10⁶), as well as H₂O (filled inverted triangles; n = 10) or FTY at a dose of 3 mg/kg (filled triangles; n = 10) or 6 mg/kg (×’s; n = 7), from day –2 pre-BMT until day 29 post-BMT. FTY was given at a dose of 3 mg/kg beginning on day 0 to an additional allogeneic group until day 29 post-BMT (filled circles; n = 3), or until day 100 post-BMT (+’s; n = 4). Syngeneic control groups received 5 × 10⁶ B6D2F1 BMCs, as well as H₂O (open inverted triangles; n = 5), different doses of FTY from day –2 until day 29 (3 mg/kg, open triangles, n = 5; 6 mg/kg, asterisks, n = 5), or 3 mg/kg FTY from day 0 until day 29 (open circles; n = 5).

Figure 3

FTY reduces GvHD-associated tissue infiltration. Large-bowel tissues are shown (×50) from one representative animal in each group. Lethally irradiated B6D2F1 mice (9.75 Gy) were reconstituted with either syngeneic BMCs (5 × 10⁶) and spleen cells (1 × 10⁶) for hematopoietic rescue (n = 2), or an inoculum of haplotype-mismatched GvHD-inducing allogeneic BMCs (5 × 10⁶) and spleen cells (1 × 10⁶) from C3D2F1 mice with (n = 7) or without (n = 7) 3 mg/kg/d FTY (days 0–11 or 0–13). Tissues are from representative animals of the syngeneic control group (a), the untreated allogeneic group (b), and the FTY-treated allogeneic group (c) that were sacrificed on day 13 post-BMT.

Figure 4

FTY inhibits GvHD mortality while permitting GvL effects to be observed. Survival curves of nonleukemic control groups (a) and leukemic groups (b) are shown. (a) Nonleukemic groups received syngeneic B6D2F1 BMCs (5 × 10⁶) with either H₂O (open inverted triangles; n = 7) or FTY (3 mg/kg/d; open circles; n = 4); or they received allogeneic haplotype-mismatched C3D2F1 BMCs (5 × 10⁶) and spleen cells (3 × 10⁶) with either H₂O (filled squares; n = 10) or 3 mg/kg/d FTY from day 0 until day 29 post-BMT (filled triangles; n = 10). (b) Leukemic groups received 5,000 EL4 cells on day 0. Mice received 5 × 10⁶ syngeneic B6D2F1 BMCs alone (×’s; n = 6) or with FTY (3 mg/kg/d; open diamonds; n = 6). Allogeneic groups received haplotype-mismatched C3D2F1 BMCs (5 × 10⁶) and spleen cells (1 × 10⁶) with either H₂O (filled inverted triangles; n = 10) or FTY treatment (*; n = 10).

Figure 5

FTY reduces clinical GvHD while preserving GvL. (a) Mortality. (b and c) Weight curves of the syngeneic (b) and allogeneic (c) groups. Lethally irradiated B6D2F1 mice received haplotype-mismatched allogeneic C3D2F1 BMCs (5 × 10⁶) and spleen cells (1 × 10⁶), with either H₂O (filled squares; n = 10) or 3 mg/kg FTY treatment from day 0 until day 29 post-BMT (filled triangles; n = 10). Five thousand EL4 cells were administered to allogeneic groups on the day of BMT with H₂O (filled inverted triangles; n = 10) or with FTY treatment (open diamonds; n = 10). Syngeneic control groups received 5 × 10⁶ B6D2F1 BMCs with H₂O (open inverted triangles; n = 5), with FTY (3 mg/kg; open circles; n = 5), or with 5,000 EL4 cells (×’s; n = 5).