Ex vivo activated immune cells promote survival and stimulate multilineage hematopoietic recovery in myelosuppressed mice.

Recovery of multilineage hematopoiesis from severe myelosuppression due to chemotherapy and radiotherapy remains a clinical problem. The authors have developed a simple immunotherapy to treat this disease in a mouse model. Syngeneic spleen cells or xenogeneic human peripheral mononuclear cells were cultured ex vivo with a combination of IL-2 at 500 IU/mL, GM-CSF at 200 U/mL, and calcium ionophore A23187 at 100 ng/mL for 2 days and injected intravenously into mice that had previously received a lethal dose of carboplatin and radiation. The therapy was highly effective: a single injection of activated cells enhanced survival and simulated multilineage recovery of hematopoiesis. Ex vivo activated immune cells produced multiple cytokines, including several hematopoietic growth factors. Adherent cells were found to be more potent than nonadherent cells in promoting survival, and the therapy alone was capable of mobilizing peripheral blood stem cells in normal mice.

Ex vivo immunotherapy for patients with benzene-induced aplastic anemia.

Aplastic anemia is a bone marrow failure disorder characterized by pancytopenia and a hypocellular marrow. Benzene is one of the etiologic agents capable of inducing the disease. With modest to severe aplastic anemia, one previously untreated patient and 13 patients who had failed immunosuppressive therapy were studied. Peripheral blood mononuclear cells from patients were expanded in vitro with a combination of cytokines and a calcium-mobilizing agents for 2 days, and the activated cells were infused intravenously once a week. In some cases, we used allogenic leukocytes instead of autologous cultured lymphocytes. After 6-35 weeks of the treatment, all patients had multilineage responses to this therapy and achieved complete disease remission, defined as normal blood count, independence from transfusion, and normal bone marrow histology. The therapy was safe and well tolerated with minimal side effects. The cultured cells produced interleukin-1 and induced immune responses in vivo. Serum interleukin-2 and interferon- gamma were detected following cell infusion. Finally, patients had sustained responses to the therapy and no relapse was found up to 18 months after cellular therapy.

[Effect of immunocyte therapy on benzene-induced bone marrow haemopoietic dysfunction].

OBJECTIVE: To explore the effect of treatment with immunocyte therapy on benzene-induced haemopoietic dysfunction. METHODS: Mono-nuclear cells (MNC) were separated from 40 - 50 ml peripheral blood in patients and mixed with interleukin-2 and granulocyte macrophage colony stimulating factor (GM-CSF) for six day cultivation. The new formed immunocytes were collected and transfused into the patients. Bone marrow aspiration and biopsy were taken before and after therapy for all patients with severe benzene poisoning. Blood samples were stained by flow cytometry for detecting CD(4) and CD(8) positive cells. RESULTS: Of 20 patients with chronic benzene poisoning, 9 were severe benzene poisoning. All examination including blood count, bone marrow biopsy and T cell subpopulation restored to normal after immunocyte therapy. Laboratory tests (liver and kidney function, and myocardial enzymes) were observed periodically and showed normal during therapy. Follow-up study (the longest time was more than 15 months) showed that bone marrow haemopietic function of all treated patients were in normal range. CONCLUSION: Bone marrow haemopoietic dysfunction caused by benzene poisoning may be closely related to disorder of immune function. Immunocyte therapy may significantly improve bone marrow haemopoietic dysfunction induced by benzene poisoning.