Bone marrow T cells are superior to splenic T cells to induce chimeric conversion after non-myeloablative bone marrow transplantation.

BACKGROUND/AIMS: The bone marrow functions not only as the primary B-lymphocyte-producing organ but also as a secondary lymphoid organ for CD4 and CD8 cell responses and a site of preferential homing and persistence for memory T cells. Bone marrow T (BM-T) cells are distinguished from peripheral blood T cells by surface phenotype, cytokine secretion profile, and immune functions. In this study, we evaluated the alloreactive potential of donor lymphocyte infusion (DLI) using BM-T cells in mixed chimerism compared to that using spleen T (SP-T) cells. METHODS: Cells were prepared using established procedures. BM-T cells were obtained as a by-product of T-cell depletion in BM grafting and then cryopreserved for subsequent DLI. We performed DLI using BM-T cells in allogeneic mixed chimera mice on post-BMT day 21. RESULTS: When the same dose of T cells, 5-10x10(5) (Thy1.2+), fractionated from BM and spleen were administered into mixed chimeras, the BM-T group showed complete chimeric conversion, with self-limited graft-versus-host disease (GVHD) and no pathological changes. However, the SP-T group showed persistent mixed chimerism, with pathological signs of GVHD in the liver and intestine. CONCLUSIONS: Our results suggest that DLI using BM-T cells, even in small numbers, is more potent at inducing chimeric conversion in mixed chimerism than DLI using SP-T cells. Further study is needed to determine whether cryopreserved BM-T cells are an effective cell source for DLI to consolidate donor-dominant chimerism in clinical practice without concerns about GVHD.

Comparison of diarsenic oxide and tetraarsenic oxide on anticancer effects: relation to the apoptosis molecular pathway.

As2O3 has been reported to induce apoptosis and inhibit the proliferation of various human cancer cells. We evaluated the ability of a novel arsenic compound, As4O6, along with As2O3 in vitro and in vivo. To examine the levels of apoptosis of HPV 16-positive SiHa cervical cancer cell, flow cytometry and Western blotting were employed at various time intervals after two arsenic compound treatments. Ingenuity Pathway Analysis (IPA) was applied to investigate the differential cell death pathway of As4O6 and As2O3. The results showed that As4O6 was more effective in suppressing SiHa cell growth in vitro and in vivo compared to As2O3. In addition, the cell cycle was arrested at the sub-G1 phase by As4O6. Western blot analysis showed that the proliferating cell nuclear antigen (PCNA) and Bcl-XL with sequence homology to Bcl-2 were significantly suppressed by As4O6. However, the apoptosis-related proteins such as p21 and Bax were overexpressed by As4O6. IPA suggested that there is a significant difference between As2O3- and As4O6-induced cell death pathways. Taken together, As4O6 has a specific cell death pathway and possesses more potent anti-tumor effects on human cervical cancer cells in vitro and in vivo.

Protective effect of irradiated renal carcinoma expressing hepatitis B surface antigen against renal-cell carcinoma-mediated tumors.

Radiation therapy and chemotherapy have little effect on renal-cell carcinomas (RENCAs). We investigated the effect of the tumor vaccination strategy on preventing tumor formation after a challenge with RENCA. The hepatitis surface antigen (HBsAg) was used to enhance the antitumor immunity and tumor vaccination efficiency. RENCA cells expressing HBsAg (RENCA/HBS) were completely susceptible to HBsAg vaccination, which implies that HBsAg vaccination induces specific antitumor immunity against HBsAg- expressing cancer cells. As with HBsAg vaccination, vaccination with irradiated RENCA/HBS retarded tumor formation following a RENCA/HBS challenge. After HBsAg vaccination, the irradiated RENCA/HBS tumor vaccine completely prevented the tumor formation by RENCA/HBS. Tumor vaccination with irradiated RENCA/HBS (5 x 10(4) cells), but not with RENCA, reduced the tumor rate after a challenge with 5 x 10(6) RENCA cells, whereas a lower tumor load was overcome by the RENCA vaccination alone. These results confirm the postulate that RENCA/HBS vaccination elicits an antitumor immune response to some putative antigens or enhances the general immune competence in immunosuppressed renal tumor patients.

Immunoregulatory effects of allogeneic mixed chimerism induced by nonmyeloablative bone marrow transplantation on chronic inflammatory arthritis and autoimmunity in interleukin-1 receptor antagonist-deficient mice.

OBJECTIVE: To investigate the immunoregulatory effects of allogeneic mixed chimerism induced by T cell-depleted, nonmyeloablative bone marrow transplantation (BMT) on chronic inflammatory arthritis and autoimmunity in mice deficient in interleukin-1 receptor antagonist (IL-1Ra). METHODS: IL-1Ra(-/-) mice (H-2K(d)) were treated with antibody to asialoganglioside G(M1) (anti-natural killer cell), total body irradiation (500 cGy), and T cell-depleted, nonmyeloablative BMT derived from C57BL/6 mice (H-2K(b)). Engraftment and chimerism were evaluated in peripheral blood, lymph nodes, and spleen by multicolor flow cytometry. The severity of arthritis was evaluated by clinical scoring and histopathologic assessment. Levels of IgG1 and IgG2a subtypes of anti-type II collagen (anti-CII) antibodies were measured in serum samples. After T cells were stimulated with CII, ovalbumin, and phytohemagglutinin, T cell proliferative responses and levels of cytokine production (interferon-gamma [IFNgamma], tumor necrosis factor alpha [TNFalpha], interleukin-10 [IL-10], and IL-17) were assayed in culture supernatants. RESULTS: All IL-1Ra(-/-) mice receiving BMT showed marked improvement in arthritis within 3 weeks, as well as successful induction of mixed chimerism. These mice showed higher levels of IgG1, and lower levels of IgG2a anti-CII antibodies and weaker T cell proliferative responses than did mice in the control groups (either no treatment or conditioning alone without bone marrow rescue). In mixed chimeras, the levels of IFNgamma, TNFalpha, and IL-17 produced from CII-stimulated T cells were significantly suppressed and IL-10 production was significantly higher as compared with controls. CONCLUSION: The introduction of allogeneic mixed chimerism showed a strong immunoregulatory potential to correct established chronic inflammatory arthritis and autoimmunity originating from a dysregulated proinflammatory cytokine network.

Successful treatment with splenectomy and interferon alpha against recurred hemophagocytic syndrome in remission state of anaplastic large cell lymphoma following high-dose therapy and autologous peripheral blood stem cell transplantation.

A 25-yr-old man had been diagnosed as having CD30(+) anaplastic large cell lymphoma associated with hemophagocytic syndrome (HS). He received aggressive frontline chemotherapies and consolidation with autologous peripheral blood stem cell transplantation (PBSCT) following high-dose chemotherapy combined with splenic irradiation (720 cGy in fraction of 180 cGy). However, HS recurred on day 50 of PBSCT without radiologic evidence of lymphoma relapse. On day 56 of PBSCT, splenectomy was performed and pathology showed massive sinusoidal infiltration of histiocytes. On day 68 of PBSCT, administration of interferon alpha was started and maintained for 24 months. HS was completely resolved and he has been alive well and in complete remission (CR), 60 months after initial diagnosis.