Plasma Microbial Cell-free DNA Next-generation Sequencing in the Diagnosis and Management of Febrile Neutropenia.

Background: Standard testing fails to identify a pathogen in most patients with febrile neutropenia (FN). We evaluated the ability of the Karius microbial cell-free DNA sequencing test (KT) to identify infectious etiologies of FN and its impact on antimicrobial management.

Methods: This prospective study (ClinicalTrials.

Detection of microbial cell-free DNA in maternal and umbilical cord plasma in patients with chorioamnionitis using next generation sequencing.

Background: Chorioamnionitis has been linked to spontaneous preterm labor and complications such as neonatal sepsis. We hypothesized that microbial cell-free (cf) DNA would be detectable in maternal plasma in patients with chorioamnionitis and could be the basis for a non-invasive method to detect fetal exposure to microorganisms.

Objective: The purpose of this study was to determine whether next generation sequencing could detect microbial cfDNA in maternal plasma in patients with chorioamnionitis.

Plasma Cell-Free DNA Next-Generation Sequencing to Diagnose and Monitor Infections in Allogeneic Hematopoietic Stem Cell Transplant Patients.

Allogeneic hematopoietic stem cell transplant patients are at risk for common and atypical infections. Superior diagnostics can decrease infection-related morbidity and mortality. A novel plasma cell-free DNA next-generation sequencing test detected an uncommon presentation of and recurrent and metastatic complications of bacteremia before standard microbiology.

Correlation between dengue-specific neutralizing antibodies and serum avidity in primary and secondary dengue virus 3 natural infections in humans.

Although heterotypic secondary infection with dengue virus (DENV) is associated with severe disease, the majority of secondary infections are mild or asymptomatic. The mechanisms of antibody-mediated protection are poorly understood. In 2010, 108 DENV3-positive cases were enrolled in a pediatric hospital-based study in Managua, Nicaragua, with 61 primary and 47 secondary infections.

Convergent antibody signatures in human dengue.

Dengue is the most prevalent mosquito-borne viral disease in humans, and the lack of early prognostics, vaccines, and therapeutics contributes to immense disease burden. To identify patterns that could be used for sequence-based monitoring of the antibody response to dengue, we examined antibody heavy-chain gene rearrangements in longitudinal peripheral blood samples from 60 dengue patients. Comparing signatures between acute dengue, postrecovery, and healthy samples, we found increased expansion of B cell clones in acute dengue patients, with higher overall clonality in secondary infection.

Dominant cross-reactive B cell response during secondary acute dengue virus infection in humans.

The four serotypes of dengue virus (DENV) cause dengue fever (DF) and dengue hemorrhagic fever/dengue shock syndrome (DHF/DSS). Severe disease has been associated with heterotypic secondary DENV infection, mediated by cross-reactive antibodies (Abs) and/or cross-reactive T cells. The role of cross-reactive immunity in mediating enhanced disease versus cross-protection against secondary heterotypic DENV infection is not well defined.

Animal models of dengue virus infection.

The development of animal models of dengue virus (DENV) infection and disease has been challenging, as epidemic DENV does not naturally infect non-human species. Non-human primates (NHPs) can sustain viral replication in relevant cell types and develop a robust immune response, but they do not develop overt disease. In contrast, certain immunodeficient mouse models infected with mouse-adapted DENV strains show signs of severe disease similar to the 'vascular-leak' syndrome seen in severe dengue in humans.

Protection from secondary dengue virus infection in a mouse model reveals the role of serotype cross-reactive B and T cells.

The four dengue virus (DENV) serotypes cause dengue fever and dengue hemorrhagic fever/dengue shock syndrome. Although severe disease has been associated with heterotypic secondary DENV infection, most secondary DENV infections are asymptomatic or result in classic DF. The role of cross-reactive immunity in mediating cross-protection against secondary heterotypic DENV infection is not well understood.

A mouse model for studying dengue virus pathogenesis and immune response.

A small animal model for studying dengue disease is of critical importance to furthering many areas of dengue research, including host immunity, disease pathogenesis, and drug and vaccine development. Recent characterization of the AG129 mouse model has demonstrated it to be one of the only models at this time that permits infection by all four serotypes of dengue virus (DENV), supports replication in relevant cell and tissue types comparable to human infection, and allows antibody-mediated protection and enhancement of DENV infection. Thus, this model enables testing hypotheses arising from epidemiological observations and in vitro experiments in an in vivo system with a functional adaptive immune response.

Phospholipase C-gamma2 is essential for NK cell cytotoxicity and innate immunity to malignant and virally infected cells.

Phospholipase C-gamma2 (PLC-gamma2) is a key component of signal transduction in leukocytes. In natural killer (NK) cells, PLC-gamma2 is pivotal for cellular cytotoxicity; however, it is not known which steps of the cytolytic machinery it regulates. We found that PLC-gamma2-deficient NK cells formed conjugates with target cells and polarized the microtubule-organizing center, but failed to secrete cytotoxic granules, due to defective calcium mobilization.

The absence of Grb2-associated binder 2 (Gab2) does not disrupt NK cell development and functions.

Scaffolding molecules bind simultaneously and link together various components of signal-transduction pathways. Grb2-associated binder 2 (Gab2) is a scaffolding protein required for FcgammaR-initiated allergic responses in mast cells and FcgammaR-mediated phagocytosis in macrophages, where it links IgE and IgG receptors to the phosphatidylinositol-3 kinase (PI-3K) pathway. The FcgammaR expressed by natural killer (NK) cells triggers antibody-dependent cellular cytotoxicity (ADCC).

Clonality analysis of alveolar B lymphocytes contributes to the diagnostic strategy in clinical suspicion of pulmonary lymphoma.

The diagnostic procedure of chronic pulmonary opacities may envisage the search for non-Hodgkin lymphoma (NHL). Previous retrospective studies have shown that clonality analysis of bronchoalveolar B lymphocytes could reflect the clonality of pulmonary lymphocytes. Our objective was to define the diagnostic usefulness of bronchoalveolar lavage (BAL) B-lymphocyte clonality analysis in the setting of a clinical suspicion of both primary and secondary pulmonary lymphoma.

P-glycoprotein and multidrug resistance associated protein-1 activity in 132 acute myeloid leukemias according to FAB subtypes and cytogenetics risk groups.

Background And Objectives: We studied the function of both Pgp and MRP1 to identify subgroups of patients who could benefit from Pgp reversion, and to clarify in different FAB subtypes and in cytogenetic risk groups their expression and function.

Design And Methods: We examined 132 adults with de novo acute myeloid leukemia (AML) for Pgp and MRP1 expression and function. We correlated our finding with the FAB subtypes and the cytogenetics, and clinical data of our patients.

NKG2D triggers cytotoxicity in mouse NK cells lacking DAP12 or Syk family kinases.

In activated mouse natural killer (NK) cells, the NKG2D receptor associates with two intracellular adaptors, DAP10 and DAP12, which trigger phosphatidyl inositol 3 kinase (PI3K) and Syk family protein tyrosine kinases, respectively. Here we show that cytotoxicity, but not cytokine production, is triggered by NKG2D in activated NK cells lacking either DAP12 or the Syk family members Syk and ZAP70. Inhibition of PI3K blocks this cytotoxicity, suggesting that the DAP10-PI3K pathway is sufficient to initiate NKG2D-mediated killing of target cells.

Therapy-related acute myeloid leukemia and myelodysplasia after successful treatment of acute promyelocytic leukemia.

The incidence of therapy-related myelodysplasia (t-MDS) and therapy-related acute myeloid leukemia (t-AML). following a high-dose chemotherapy for a prior cancer, is progressively increasing. Here we review patients treated by conventional therapy for acute promyelocytic leukemia (APL) who developed a t-MDS or t-AML in the course of their disease.