Clinical-grade manufacturing of autologous mature mRNA-electroporated dendritic cells and safety testing in acute myeloid leukemia patients in a phase I dose-escalation clinical trial.

BACKGROUND AIMS: RNA-electroporated dendritic cell (DC)-based vaccines are rapidly gaining interest as therapeutic cancer vaccines. We report on a phase I dose-escalation trial using clinical-grade manufactured mature RNA-electroporated DC in acute myeloid leukemia (AML) patients. METHODS: CD14(+) cells were isolated from leukapheresis products by immunomagnetic CliniMACS separation and differentiated into mature DC (mDC). mDC were electroporated with clinical-grade mRNA encoding the Wilm's tumor (WT1) antigen, and tested for viability, phenotype, sterility and recovery. To test product safety, increasing doses of DC were administered intradermally four times at 2-week intervals in 10 AML patients. RESULTS: In a pre-clinical phase, immunomagnetic monocyte isolation proved superior over plastic adherence in terms of DC purity and lymphocyte contamination. We also validated a simplified DC maturation protocol yielding a consistent phenotype, migration and allogeneic T-cell stimulatory capacity in AML patients in remission. In the clinical trial, highly purified CD14(+) cells (94.5+/-3.4%) were obtained from all patients. A monocyte-to-mDC conversion factor of 25+/-10% was reached. All DC preparations exhibited high expression of mDC markers. Despite a decreased cell recovery of mDC after a combination of mRNA electroporation and cryopreservation, successful vaccine preparations were obtained in all AML patients. DC injections were well tolerated by all patients. CONCLUSIONS: Our method yields a standardized, simplified and reproducible preparation of multiple doses of clinical-grade mRNA-transfected DC vaccines from a single apheresis with consistent mature phenotype, recovery, sterility and viability. Intradermal injection of such DC vaccines in AML patients is safe.

Adult acute precursor B-cell lymphoblastic leukemia presenting as hypercalcemia and osteolytic bone lesions.

BACKGROUND: Osteolytic bone lesions and hypercalcemia without peripheral blasts B-cell acute lymphoblastic leukemia (B-ALL) is reported in children but rarely seen in adults. CASE PRESENTATION: We describe the case of a 34-year old man presenting with hypercalcemia and symptomatic osteolytic bone lesions of vertebrae and ribs who was initially suspected as having a solid malignancy. Diagnostic work-up including peripheral blood examination, radiographic and nuclear studies could, however, not detect a primary tumor. Because of a mild thrombocytopenia and the lack of a primary focus, a bone marrow biopsy was performed leading to the diagnosis of Philadelphia chromosome positive precursor B-ALL. After correction of the hypercalcemia with intravenous fluid administration, corticoids and bisphosphonates, the patient was treated according to the HOVON 100 protocol achieving complete molecular remission after the first cycle of induction chemotherapy. CONCLUSION: Hypercalcemia and osteolytic bone lesions are rare complications of adult B-ALL and can occur in the absence of peripheral blastosis. With this case report we would like to emphasize the importance of clinical awareness. Immediate treatment of hypercalcemia and initiation of antileukemic treatment is mandatory as a delay of diagnosis might pose a real and possible life-threatening risk in these patients.

Immunotherapy of hematological malignancies using dendritic cells.

The arsenal of therapeutic weapons against hematological malignancies is constantly growing. Unravelling the secrets of tumor immunobiology has allowed researchers to manipulate the immune system in order to stimulate tumor immunity or to bypass tumor-induced immunosuppression. An area of great interest is active specific immunotherapy where dendritic cell (DC)-based therapeutic vaccines for cancer have definitely grabbed the spotlight. DC are intensively investigated as cellular adjuvants to harness the immune system to fight off cancer by augmenting the number and effector functions of tumor-specific CD8+ cytotoxic T lymphocytes. In the present review we present a comprehensive synopsis and an update of the use of DC in hematological malignancies. In the future, more basic research as well as more clinical trials are warranted to fully establish the value of DC vaccination as an adjuvant therapy for modern hematological oncology.

Primary non-Hodgkin's lymphoma in Bartholin's gland.

BACKGROUND: Non-Hodgkin's lymphoma (NHL) may involve the lower female genital tract, most often as a manifestation of systemic disease and rarely as a primarily localisation. CASE: A 73-year-old woman, HIV-negative, presented with a 5-month history of a mass in the left Bartholin's gland. The performed biopsy was reported to be a poorly differentiated carcinoma. Therefore, the patient underwent a vulvectomy with superficial groin node dissection. Unexpectedly, the definitive histological diagnosis showed that the tumor was an extranodal diffuse large B-cell non-Hodgkin lymphoma. CONCLUSION: This is the first report of a NHL located in the Bartholin's gland. Primary NHLs involving the external genitalia are rare and often inaccurately diagnosed. A greater awareness of this entity among clinicians and pathologists could uncover more cases.