Chemotherapy before donor lymphocyte infusion enhances lymphocyte activation and induces clinical responses

Animal models have demonstrated that the serum peak concentration of activating cytokines and hematopoietic growth factors is reached 48 hours after a chemotherapeutic treatment. We hypothesized that patients affected by resistant diseases who have already undergone an allogeneic SCT may benefit from adoptive cell transfer performed after chemotherapy. Four high risk patients affected by AML evolved from a MDS, who already presented a disease recurrence after an allogeneic SCT (1 from haplo, 1 from MUD and 2 from siblings), completed 2 cycles of DLI (CD3 = 1 x [10.sup.7]/Kg of recipient BW for haplo and MUD, and 1 x [10.sup.8]/Kg for sibling) performed 2 days after a lymphodepleting chemotherapeutic treatment. These patients underwent cytofluorimetric analysis of the PB for CD3, CD4, CD8, CD25, CD16, CD56, CD20, CD7, CD38, HLA-DR and intracytoplasmic staining for IFNg, TNFa, IL-2, IL-10 at days 0, 2, 5, 10, 20, 30 from DLI; two patients who underwent 2 cycles of standard DLI served as controls. The results demonstrated that from day 2 throughout the entire study period, patients who received DLI after chemotherapy showed an increased presence of reactive elements, as documented by lymphocytes expressing the CD7/CD38/HLA-DR profile when compared to controls (p 0.0001). The difference reached its maximum at day 5 (mean % ± S.D. 40 ± 21 vs 8 ± 3; p 0.02). The production of IFNg was also superior in patients from the study group (p 0.01), achieving the peak at day 10 (mean % ± S.D. 36 ± 11 vs 16 ± -4; p 0.01). Three of the 4 patients from the study group presented for the first time a clinical picture of GVHD in association with the chemo-immunotherapeutic treatment (despite having previously undergone many cycles of standard DLI); in these 3 patients, the onset of GVHD was associated with an hematologic CR. The first patient is now in CR 19 months later (which represents the longest CR from the transplant performed 5 years ago); the second patient remains in CR after more than 5 months; the third patient obtained a CR, but died of pneumonia 2 months after the treatment; the fourth patient, who did not show GVHD, has relapsed. These observations suggest that donor lymphocytes may undergo a process of activation when infused into patients who have received a chemotherapy in the last 2 days and advocate a possible new chemo-immonotherapeutic schedule that can be taken into consideration in the case of resistant/residual diseases for patients who have undergone a