Evaluation of a Multiplex Bead Assay against Single-Target Assays for Detection of IgG Antibodies to SARS-CoV-2.

Serological assays for SARS-CoV-2 antibodies must be validated for performance with a large panel of clinical specimens. Most existing assays utilize a single antigen target and may be subject to reduced diagnostic specificity. This study evaluated a multiplex assay that detects antibodies to three SARS-CoV-2 targets.

Evaluation of anti-factor VIII antibody levels in patients with haemophilia A receiving immune tolerance induction therapy or bypassing agents.

Introduction: Bleeding episodes in patients who have haemophilia A (HA), a hereditary bleeding disorder caused by a deficiency in factor VIII (FVIII), are treated or prophylactically prevented with infusions of exogenous FVIII. Neutralizing antibodies, referred to as inhibitors, against infusion products are a major complication experienced by up to 30% of patients who have severe HA. Bypassing agents (BPA), a class of therapeutics given to patients who have inhibitors, bypass the need for FVIII in the coagulation cascade, and long-term inhibitor eradication is accomplished using immune tolerance induction therapy (ITI).

An Observational Study from Long-Term AAV Re-administration in Two Hemophilia Dogs.

Adeno-associated virus (AAV) vectors have been successfully applied in hemophilia clinical trials. However, this approach is limited to patients without AAV-neutralizing antibodies (NAbs). In this study, we explored the feasibility of AAV re-administration in hemophilia A dogs treated initially 8 years ago with AAV8.

Complete correction of hemophilia B phenotype by FIX-Padua skeletal muscle gene therapy in an inhibitor-prone dog model.

Skeletal muscle–directed expression of FIX-Padua resulted in complete correction of HB phenotype in an inhibitor-prone dog model. Long-term immune tolerance to FIX is sustained over years upon multiple challenges with recombinant FIX protein in 2 HB models.

AAV liver expression of FIX-Padua prevents and eradicates FIX inhibitor without increasing thrombogenicity in hemophilia B dogs and mice.

Emerging successful clinical data on gene therapy using adeno-associated viral (AAV) vector for hemophilia B (HB) showed that the risk of cellular immune response to vector capsid is clearly dose dependent. To decrease the vector dose, we explored AAV-8 (1-3 × 10(12) vg/kg) encoding a hyperfunctional factor IX (FIX-Padua, arginine 338 to leucine) in FIX inhibitor-prone HB dogs. Two naïve HB dogs showed sustained expression of FIX-Padua with an 8- to 12-fold increased specific activity reaching 25% to 40% activity without antibody formation to FIX.

Decreased hematopoietic progenitor cell mobilization in pearl mice.

Neutropenia is common to both Hermansky-Pudlak syndrome type 2 and canine cyclic hematopoiesis (CH) which are caused by mutations in the AP3B1 gene. The purpose of this study was to determine if pearl mice were neutropenic. Complete blood counts (CBCs) and bone marrow differential counts, colony forming unit (CFU) assay, bone marrow lineage negative (lin(-)), Sca(+) and c-kit(+) cells (LSK cells), bone marrow elastase, myeloperoxidase, and cathepsin G enzyme activity were compared in C57Bl6 (Bl/6) and pearl mice.

Neutrophil elastase-processing defect in cyclic hematopoietic dogs.

Objective: Canine cyclic hematopoiesis (CH), a model of human cyclic neutropenia and severe congenital neutropenia, is characterized by a periodic reduced neutrophil count and decreased neutrophil elastase (NE) enzymatic activity. Canine CH is caused by a mutation of AP3B1 encoding the beta3A subunit of adaptor protein complex-3 (AP-3). It has been proposed that trafficking of elastase is affected by AP-3.

Long-term correction of inhibitor-prone hemophilia B dogs treated with liver-directed AAV2-mediated factor IX gene therapy.

Preclinical studies and initial clinical trials have documented the feasibility of adenoassociated virus (AAV)-mediated gene therapy for hemophilia B. In an 8-year study, inhibitor-prone hemophilia B dogs (n = 2) treated with liver-directed AAV2 factor IX (FIX) gene therapy did not have a single bleed requiring FIX replacement, whereas dogs undergoing muscle-directed gene therapy (n = 3) had a bleed frequency similar to untreated FIX-deficient dogs. Coagulation tests (whole blood clotting time [WBCT], activated clotting time [ACT], and activated partial thromboplastin time [aPTT]) have remained at the upper limits of the normal ranges in the 2 dogs that received liver-directed gene therapy.

Hematopoietic chimerism induces renal and skin allograft tolerance in DLA-identical dogs.

Objective: Hematopoietic chimerism, a state where donor and recipient bone marrow cells coexist, is associated with donor-specific tolerance. Nonmyeloablative bone marrow transplantation (BMT) has been shown to induce stable mixed hematopoietic chimerism in dog leukocyte antigen (DLA)-matched dogs. The potential for inducing renal and skin allograft tolerance with nonmyeloablative BMT was investigated in DLA-identical and DLA-haploidentical dogs in this study.

Renal allograft histopathology in dog leukocyte antigen mismatched dogs after renal transplantation.

Objective: To evaluate allograft histopathology in dog leukocyte antigen (DLA)-mismatched dogs undergoing renal transplantation, with transient immunosuppression.

Study Design: Prospective study.

Animals: Ten healthy adult mongrel dogs.

Correction of a large animal model of type I Glanzmann's thrombasthenia by nonmyeloablative bone marrow transplantation.

Objective: The purpose of this study was to determine if nonmyeloablative bone marrow transplantation would induce stable hematopoietic chimerism that would correct the bleeding diathesis associated with type I Glanzmann's thrombasthenia (GT).

Methods: Three young dogs (less than 12 weeks of age) with GT were transplanted with DLA-matched bone marrow from littermates. Recipients received a sublethal dose (200 cGy) of total-body irradiation (TBI) prior to infusion with bone marrow (1-4 x 10(8) cells/kg).

Isolation and characterization of multipotential mesenchymal stem cells from feline bone marrow.

Objective: Although several types of stem cells have been isolated from rodent and human tissues, very few data exist on stem cell isolation from nonrodent animals, which seriously limits the advancement of stem cell biology and its ultimate translation to human clinical applications. Domestic cats are used frequently in biomedical research and are the preferred species for studies of normal physiology and disease, particularly in neuroscience. Therefore, the objective of this study was to characterize mesenchymal stem cells (MSC) from feline bone marrow for use in research on the application of stem cells to human health problems for which cats are the preferred model.