Donor lymphocytes expressing the herpes simplex virus thymidine kinase suicide gene: detailed immunological function following add-back after haplo-identical transplantation.

BACKGROUND AIMS: Haplo-identical hematopoietic stem cell transplantation (HSCT) with add-back of donor lymphocytes expressing the herpes simplex virus thymidine kinase suicide gene (TK cells) is one of the most widely applied promising new gene therapy approaches. However, the immunological status of added-back TK cells after HSCT has yet to be well characterized. METHODS: We investigated TK cells through the use of flow cytometry, T-cell receptor (TCR) Vß repertoire spectratyping and linear amplification-mediated polymerase chain reaction followed by insertion site analysis in a patient enrolled in our clinical trial. RESULTS: A comparison of onset with remission of acute graft-versus-host disease confirmed that TK cells were predominantly eliminated and that proliferative CD8(+) non-TK cells were also depleted in response to ganciclovir administration. The TCR Vß-chain repertoire of both TK cells and non-TK cells markedly changed after administration of ganciclovir, and, whereas the TCR repertoire of non-TK cells returned to a normal spectratype long after transplantation, that of TK cells remained skewed. With the long-term prophylactic administration of acyclovir, TK cells oligoclonally expanded and the frequency of spliced variants of TK cells increased. Known cancer-associated genes were not evident near the oligoclonally expanded herpes simplex virus (HSV)-TK insertion sites. CONCLUSIONS: We demonstrate obvious differences in immunological status between TK cells and non-TK cells. In addition, we speculate that long-term prophylactic administration of acyclovir increases the risk of oligoclonal expansion of spliced forms of TK cells.

Regular dose of gemcitabine induces an increase in CD14+ monocytes and CD11c+ dendritic cells in patients with advanced pancreatic cancer.

OBJECTIVE: Chemotherapy and immunotherapy often seem to contradict each other. However, recent reports suggested that the anticancer effects in some chemotherapeutic agents were concerned with immune response. This study was designed to evaluate the immunological reaction by gemcitabine for future clinical trial of combination therapy with gemcitabine and cancer vaccines. METHODS: We evaluated several immunological parameters in patients with advanced pancreatic cancer who received a conventional dose of gemcitabine for 2 months. Twenty-eight patients with metastasis or locally advanced tumor, including 18 gemcitabine-naïve and 10 with a history of preceding gemcitabine treatment, were enrolled in this study. The patients received gemcitabine 1000 mg/m(2) for 3 weeks, followed by 1 week of rest. We monitored the kinetics of lymphocytes, natural killer cells, monocytes, dendritic cells (DC), human leukocyte antigen (HLA)-multimer conjugated with CMV or WT1 peptide, and intracellular cytokine production of interferon-gamma and interleukin-4 by flow cytometry. The T cell receptor (TCR) repertoire was also analyzed. RESULTS: The absolute number and percentage of CD14(+) monocytes and CD11c(+) (myeloid) DC increased with gemcitabine treatment (P = 0.033 and P = 0.021). The percentage of CD123(+) (plasmacytoid) DC also increased (P = 0.034), whereas no significant change was observed in other immune parameters, including multimer, intracellular cytokine production and TCR repertoire. CONCLUSIONS: Our finding that gemcitabine treatment induced the proliferation of CD14(+) monocytes and CD11c(+) DC could support combination therapy with gemcitabine and specific immunotherapy such as peptide vaccination against pancreatic cancers.