Role of alpha-Hemolysin for the in vitro Phagocytosis and intracellular killing of Escherichia coli

The_role of a-hemolysin for the elimination of Eschericbia coli by phagocyres in vitro was investigated using sets of isogenic strains which included wild-type a -hemolyric srrains, derived strains with a reduced production of a-hemolysin and derived nonhemolytic strains. Phagocyrosis and intracellular killing of the bacteria by human blood granulocytes or monocytes were measured using growth inhibition rechniques. a-hemolytic strains were phagocytosed and killed ro a Jesser extent than isogenic strains with a reduced production of o:hemoJysin and isogenic nonhemolytic strains. The results obrained with granulocyres were similar to rhose obtained with monocyres although the elimination of bacteria by monocytes was less than that by granulocytes. These resulcs strongJy suggest that production of ahemolysin is a means by which E. coli counteracrs the activity of phagocytes by injuring these cells with the toxin.Die Rolle von a-Hämolysin bei der in vitro·Eliminierung von Escherichia coli durch Phagozyten wurde unter Verwendung isogener Stämme einschließlich von a-hämolysierenden Wildstämmen, davon abstammenden Stämmen mit reduzierter a-Hämolysin-Bildung und davon abstammenden nicht hämolysierenden Stämmen untersuche. Phagozytose und intrazelluläre Abtötung der Bakterien durch Granulozyten oder Monozyten im menschlieben Blut wurden u.nter Verwendung von Wachstums-Hemmtechniken gemessen. o:-hämolysierende Stämme wurden in geringerem Maße als isogene Stämme mit einer geringeren Hämolysin-Bildung und isogene nicht hämolysierende Stämme pbago:z.ytiert und ;~bgetötet. Die mit Granulozyten erzielten Ergebnisse waren den bei Monozyten ähnlich, obwohl die Bakterienelimination durch Monozyten geringer war als durch Granulozyten. Diese Ergebnisse deuten stark darauf hin, daß die Bildung von a-Hämolysin ein Mine) ist, mit dem E. coli der Aktivität der Phagozyten durch Schädigung dieser Zellen mit dem Toxin entgegenwirkt

Immunohistochemical double-hit score is a strong predictor of outcome in patients with diffuse large B-cell lymphoma treated with rituximab plus cyclophosphamide, doxorubicin, vincristine, and prednisone

Approximately 5% of diffuse large B-cell lymphomas (DLBCLs) are double-hit lymphomas (DHLs) with translocations of both MYC and BCL2. DHLs are characterized by poor outcome. We tested whether DLBCLs with high expression of MYC protein and BCL2 protein share the clinical features and poor prognosis of DHLs

Pharmacokinetics and pharmacokinetic/pharmacodynamic associations of ofatumumab, a human monoclonal CD20 antibody, in patients with relapsed or refractory chronic lymphocytic leukemia: a phase 1-2 study

International audienceThe purpose of this phase 1-2 study was to investigate the association between pharmacokinetic (PK) properties of ofatumumab, a human monoclonal CD20 antibody, and outcomes in 33 patients with relapsed/refractory chronic lymphocytic leukemia receiving 4 weekly infusions of ofatumumab. The ofatumumab concentration profiles were fitted well by a two-compartment model with different elimination rate constant at first infusion compared to the remaining infusions in line with the observed rapid and sustained B-cell depletion. Exposure to ofatumumab was linked to clinical outcomes: high exposure was associated with higher probability of overall clinical response and longer progression free survival. This association still remained statistically significant even when adjusting for relevant baseline covariates including tumor burden. The trial was registered at www.clinicaltrials.gov (NCT00093314)

The inter-city challenges

Ofatumumab is a unique monoclonal antibody that targets a distinct small loop epitope on the CD20 molecule. Preclinical data show that ofatumumab is active against B-cell lymphoma/chronic lymphocytic leukemia cells with low CD20-antigen density and high expression of complement inhibitory molecules. In a phase 1/2 trial evaluating safety and efficacy of ofatumumab in relapsed or refractory follicular non-Hodgkin lymphoma (FL) grade 1 or 2, 4 dose groups of 10 patients received 4 weekly infusions of 300, 500, 700, or 1000 mg. Patients had a median of 2 prior FL therapies and 13% had elevated lactate dehydrogenase. No safety concerns or maximum tolerated dose was identified. A total of 274 adverse events were reported; 190 were judged related to ofatumumab, most occurring on the first infusion day with Common Terminology Criteria grade 1 or 2. Eight related events were grade 3. Treatment caused immediate and profound B-cell depletion, and 65% of patients reverted to negative BCL2 status. Clinical response rates ranged from 20% to 63%. Median time to progression for all patients/ responders was 8.8/ 32.6 months, and median duration of response was 29.9 months at a median/ maximum follow-up of 9.2/38.6 months. Ofatumumab is currently being evaluated in patients with rituximab-refractory FL

Upfront Autologuos Stem-Cell Transplantation in Peripheral T-Cell Lymphoma: NLG-T-01.

PURPOSE: Systemic peripheral T-cell lymphomas (PTCLs) respond poorly to conventional therapy. To evaluate the efficacy of a dose-dense approach consolidated by upfront high-dose chemotherapy (HDT) and autologous stem-cell transplantation (ASCT) in PTCL, the Nordic Lymphoma Group (NLG) conducted a large prospective phase II study in untreated systemic PTCL. This is the final report, with a 5-year median follow-up, of the NLG-T-01 study. PATIENTS AND METHODS: Treatment-naive patients with PTCL age 18 to 67 years (median, 57 years) were included. Anaplastic lymphoma kinase (ALK) -positive anaplastic large-cell lymphoma (ALCL) was excluded. An induction regimen of six cycles of biweekly CHOEP (cyclophosphamide, doxorubicin, vincristine, etoposide, and prednisone) was administered (in patients age > 60 years, etoposide was omitted). If in complete or partial remission, patients proceeded to consolidation with HDT/ASCT. Results: Of 166 enrolled patients, 160 had histopathologically confirmed PTCL. The majority presented with advanced-stage disease, B symptoms, and elevated serum lactate dehydrogenase. A total of 115 underwent HDT/ASCT, with 90 in complete remission at 3 months post-transplantation. Early failures occurred in 26%. Treatment-related mortality was 4%. At 60.5 months of median follow-up, 83 patients were alive. Consolidated 5-year overall and progression-free survival (PFS) were 51% (95% CI, 43% to 59%) and 44% (95% CI, 36% to 52%), respectively. Best results were obtained in ALK-negative ALCL. CONCLUSION: Dose-dense induction followed by HDT/ASCT was well tolerated and led to long-term PFS in 44% of treatment-naive patients with PTCL. This represents an encouraging outcome, particularly considering the high median age and adverse risk profile of the study population. Therefore, dose-dense induction and HDT/ASCT are a rational upfront strategy in transplantation-eligible patients with PTCL