Dendritic cell vaccination as postremission treatment to prevent or delay relapse in acute myeloid leukemia.

Relapse is a major problem in acute myeloid leukemia (AML) and adversely affects survival. In this phase 2 study, we investigated the effect of vaccination with dendritic cells (DCs) electroporated with Wilms' tumor 1 (WT1) messenger RNA (mRNA) as postremission treatment in 30 patients with AML at very high risk of relapse. There was a demonstrable antileukemic response in 13 patients. Nine patients achieved molecular remission as demonstrated by normalization of WT1 transcript levels, 5 of which were sustained after a median follow-up of 109.4 months. Disease stabilization was achieved in 4 other patients. Five-year overall survival (OS) was higher in responders than in nonresponders (53.8% vs 25.0%; P = .01). In patients receiving DCs in first complete remission (CR1), there was a vaccine-induced relapse reduction rate of 25%, and 5-year relapse-free survival was higher in responders than in nonresponders (50% vs 7.7%; P < .0001). In patients age ≤65 and >65 years who received DCs in CR1, 5-year OS was 69.2% and 30.8% respectively, as compared with 51.7% and 18% in the Swedish Acute Leukemia Registry. Long-term clinical response was correlated with increased circulating frequencies of polyepitope WT1-specific CD8+ T cells. Long-term OS was correlated with interferon-γ+ and tumor necrosis factor-α+ WT1-specific responses in delayed-type hypersensitivity-infiltrating CD8+ T lymphocytes. In conclusion, vaccination of patients with AML with WT1 mRNA-electroporated DCs can be an effective strategy to prevent or delay relapse after standard chemotherapy, translating into improved OS rates, which are correlated with the induction of WT1-specific CD8+ T-cell response. This trial was registered at www.clinicaltrials.gov as #NCT00965224.

Clinical and microbiological impact of discontinuation of fluoroquinolone prophylaxis in patients with prolonged profound neutropenia.

BACKGROUND: Infections remain a leading cause of morbidity and mortality in patients with reduced immunity caused by haematological disease and chemotherapy-induced neutropenia. We evaluated the clinical and microbiological impact of discontinuing fluoroquinolone prophylaxis in these patients. METHODS: We analysed 154 admissions in three sequential periods of 8 months: long-standing use, discontinuation of prophylaxis and reintroduction of prophylaxis. Clinical endpoints were occurrence of febrile neutropenia, bacteraemia, severe sepsis, septic shock, response to antibiotic therapy, total antibiotic consumption and duration of hospital stay. Microbiological analysis included bacterial isolates from stool and blood cultures and their resistance pattern. RESULTS: No significant increase in serious infectious complications was seen with the discontinuation of prophylaxis. The overall incidence of bacteraemia did not change, but a higher proportion of bacterial isolates were Gram-negative (22.2% vs. 5.9% & 8.6%; P = 0.030), more often multisusceptible (50% vs. 0%) and less fluoroquinolone resistant (10% vs. 100%). Screening of stools showed a higher prevalence of organisms in the discontinuation period (86.7% vs. 37.3% & 55.2%; P ≤ 0.001), but they were more frequently multisusceptible (53.8% vs. 10.5% & 6.3%; P ≤ 0.001). After discontinuation of prophylaxis, fluoroquinolone resistance decreased rapidly from 73.7 to 7.7%, in association with a significant decrease in extended spectrum beta-lactamase (ESBL)-producing isolates from 42.1 to 10.3%. Resistance figures immediately returned to prediscontinuation values after reinstitution of prophylaxis. CONCLUSIONS: No clinically relevant short-term drawbacks were observed with the discontinuation of fluoroquinolone prophylaxis in patients with chemotherapy-induced prolonged profound neutropenia, which led to a significant decrease in fluoroquinolone resistance as well as occurrence of ESBL-producing isolates.

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.

Comparison of the Power of Procalcitonin and C-Reactive Protein to Discriminate between Different Aetiologies of Fever in Prolonged Profound Neutropenia: A Single-Centre Prospective Observational Study.

Management of fever in prolonged, profound neutropenia remains challenging with many possible infectious and non-infectious causes. We investigated whether procalcitonin (PCT) is superior to C-reactive protein (CRP) in discriminating between different aetiologies of fever in this setting. CRP and PCT were tested daily during 93 neutropenic episodes in 66 patients. During this study period, 121 febrile episodes occurred and were classified into four categories based on clinical and microbiological findings: microbiologically documented infection (MDI); clinically documented infection (CDI); proven or probable invasive fungal disease (IFD); fever of unknown origin (FUO). Values of PCT and CRP at fever onset as well as two days later were considered for analysis of their performance in distinguishing aetiologies of fever. At fever onset, no significant difference in PCT values was observed between different aetiologies of fever, whereas median CRP values were significantly higher in case of IFD (median 98.8 mg/L vs 28.8 mg/L, p=0.027). Both PCT and CRP reached their peak at a median of 2 days after fever onset. Median PCT values on day 2 showed no significant difference between the aetiologies of fever. Median CRP values on day 2 were significantly higher in IFD (median 172 mg/L versus 78.4 mg/L, p=0.002). In MDI median CRP values rose > 100 mg/L, whereas they did not in CDI or FUO. PCT has no added value over CRP for clinical management of fever in prolonged, profound neutropenia. When performing reassessment 2 days after fever onset, CRP has better discriminatory power between aetiologies of fever.

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.