Five-year clinical effects of donor bone marrow cells infusions in kidney allograft recipients: improved graft function and higher graft survival.

Augmentation of microchimerism in solid organ transplant recipients by donor bone marrow cells (DBMC) infusion may promote immune hyporesponsiveness and consequently improve long-term allograft survival. Between March 2005 and July 2007, outcomes for 20 living unrelated donor (LURD) primary kidney recipients with concurrent DBMC infusion (an average of 2.19 ± 1.13 x 109 donor cells consisting of 2.66 ± 1.70 x 107 CD34⁺ cells) were prospectively compared with 20 non-infused control allograft recipients given similar conventional immunosuppressive regimens. With five years of clinical follow up, a total of 11 cases experienced rejection episodes (3 DBMI patients vs. 8 controls, p = 0.15). One DBMC-infused patient experienced chronic rejection vs. two episodes (1 biopsy-confirmed) in the control patients. Actuarial and death-censored 5-y graft survival was significantly higher in infused patients compared with controls (p = 0.01 and p = 0.03, respectively). Long-term graft survival was significantly associated with pre-transplant anti-HLA antibodies (p = 0.01), slightly with peripheral microchimerism (p = 0.09) and CD4⁺CD25⁺FoxP3⁺ T cells (p = 0.09). Immunosuppressant dosing was lower in infused patients than controls, particularly for mycophenolate mofetil (p = 0.001). The current findings as well as our previous reports on these patients indicates clinical improvement in long-term graft survival of renal transplant patients resulting from low-dose DBMC infusion given without induction therapy.

Regulatory T-cell subset analysis and profile of interleukin (IL)-10, IL-17 and interferon-gamma cytokine-producing cells in kidney allograft recipients with donor cells infusion.

BACKGROUND: This pilot study aimed to assess whether the perioperative infusion of donor bone marrow cells (DBMC) in renal allograft recipients can affect the appearance of peripheral regulatory T-cell subsets and the profile of cytokine-producing cells [interferon-gamma (IFN-γ), interleukin (IL)-17 and IL-10] 2 years after transplantation. METHODS: Fresh blood samples were collected from 14 kidney recipients who received infusion and from 13 kidney recipients without infusion who served as controls at the end of the second post-transplantation year. Initially the percentages of CD4(+)CD25(+)FoxP3(+) T cells and CD3(+)CD8(+)CD28(-) T cells were quantified using flowcytometry. Thereafter, the frequencies of IL-10-, IL-17- and IFN-γ-producing cells were determined separately using the ELISPOT technique with peptides corresponding to mismatched donor HLA-DR molecules and phytohemagglutinin (PHA). RESULTS: The mean numbers of IFN-γ- and IL-17-producing cells in response to PHA were lower in infused patients than in controls (P = 0.02 and P = 0.18, respectively); however, an increased frequency of IL-10-producing cells was observed compared to controls (P = 0.07). Furthermore, the ratio of IL-10/IFN-γ-producing cells was significantly higher in the DBMC-infused group versus controls (P = 0.01). There was a negative correlation between the percentage of CD3(+)CD8(+)CD28(-)T cells and IL-17-producing cells in the infused group (r = -0.539, P = 0.04). The mean levels and the frequency of microchimerism within the first post-transplantation year were also significantly higher in infused patients than in controls (P = 0.007 and P = 0.001, respectively). CONCLUSION: Our findings suggest that DBMC infusion could partially stimulate the regulatory mechanisms against alloimmune responses in kidney allograft recipients

Antitumor and immunomodulatory properties of artemether and its ability to reduce CD4+ CD25+ FoxP3+ T reg cells in vivo.

BACKGROUND: Development of agents that specifically kill cancer cells and simultaneously elicit antitumor immune response is a step forward in cancer therapy. In the present study, we investigated whether the administration of artemether contributes to the augmentation of antitumor immunity and the regression of tumor tissues in a mouse model of breast cancer. METHODS: An optimal immunostimulatory dose of artemether (ART) was defined by DTH reaction and antibody production in sRBC-challenged mice. Subsequent experiments were carried out on tumor-bearing BALB/c mice. In the first group of tumor-bearing mice, the dose of 10 mg/kg/day of artemether were intraperitoneally administered to each animal for six times. The second group was treated with 20 mg/kg/day of cyclophosphamide as a positive control, and the last group (negative control) received the ART diluents. Tumor size was measured during the 10-day experiment; on the last day, mice were sacrificed and their splenocytes and tumor infiltrating lymphocytes were harvested. The concentration of IL-4 and IFN-γ cytokines (using ELISA assay) and the percentage of splenic and tumor Treg cells (using Flowcytometry analysis) were measured. RESULTS: Artemether could increase both DTH reaction and the production of hemagglutinating antibody in normal mice. Administration of ART profoundly suppressed the progression of tumor tissues. As well, it was significantly effective in the depletion of splenic CD4+ CD25+ Foxp3+ Treg cells (p-value>0.05). ART also increased the production of IL-4 (p-value<0.05) and IFN-γ (p-value>0.05). As a conclusion, the cytotoxic and immunomodulatory properties of artemether were acknowledged in vivo.