Use of Low-Dose Platelets in Actively Bleeding Patients: A Retrospective Analysis of a Cardiac Surgery Cohort.

CONTEXT.­: During platelet shortages, many hospitals produce low-dose platelets by splitting a standard platelet unit (>3 × 1011 platelets in the United States) in 2, then providing these low-dose units to patients. While low-dose units were previously found to be effective for prophylactic purposes in patients undergoing chemotherapy in the Prophylactic Platelet Dose (PLADO) trial, their use in actively bleeding patients has not yet been assessed. OBJECTIVE.­: To assess the use and safety of low-dose platelets in actively bleeding patients. DESIGN.­: We performed a retrospective review of cardiac surgery cases receiving platelet units for 18 months at 1 hospital. Two cohorts, those receiving only whole-dose platelets (37 cases) and those receiving only low-dose platelets (38 cases), were compared during the intraoperative and the 24-hour perioperative period. Mean number of platelet transfusions, dose of other blood products, estimated blood loss, bleeding complications in index cases, and all-cause mortality within 30 days of discharge were compared. RESULTS.­: There was no significant difference in mean number of intraoperative platelet transfusions between the cohorts (1.61 versus 1.53, P = .57). There was no significant increase in the transfusion of other blood products, estimated blood loss, bleeding complications in index cases, or all-cause mortality within 30 days of discharge in the low-dose platelet cohort, apart from a small increase in requirement for fresh frozen plasma in the perioperative period. CONCLUSIONS.­: These results suggest that low-dose platelets are tentatively equivalent to whole-dose platelets in cardiac surgery during shortages, with similar transfusion requirements and clinical outcomes between groups. Future multicenter studies are needed to confirm these findings.

Therapeutic plasma exchange for the treatment of refractory necrotizing autoimmune myopathy.

INTRODUCTION: Necrotizing autoimmune myopathy (NAM) is strongly associated with pathognomonic autoantibodies targeting 3-hydroxy-3-methylglutaryl-coenzyme A reductase (HMGCR) or signal recognition particle (SRP), whose levels in turn are correlated with serum creatine kinase (CK) and necrosis. Thus, NAM may be amenable to therapeutic plasma exchange (TPE) to remove pathogenic antibodies and improve patient symptoms. METHODS: A retrospective case series and literature review of patients presenting with NAM and undergoing treatment with TPE was performed. Clinical data including patient demographics, symptoms, physical exam findings, muscle biopsy, lower extremity imaging, prior therapy, and duration from diagnosis to TPE initiation were collected retrospectively for adult patients with NAM treated with TPE after failing to respond to immunomodulatory therapy. Laboratory data including change in CK levels and myositis-specific antibody titers from baseline were measured in some patients. RESULTS: Six patients (median age at diagnosis 52.5 years, interquartile range [IQR] 35.8-64.5 years, four male/two female) underwent a median of 7.5 (IQR: 5-10) TPE procedures with 5% albumin as replacement. All patients exhibited a statistically significant reduction in CK level from pre-TPE baseline (range: 43.0%-58.7% reduction). Responses in this cohort were best in patients with antibodies targeting HMGCR and SRP, which are most strongly associated with NAM. These results compare favorably to a literature review of NAM patients (n = 19) treated with TPE, who also exhibited positive clinical and laboratory responses across varying treatment lengths. CONCLUSION: TPE can play a role in the management of NAM, particularly in patients with HMGCR or SRP antibodies who are refractory to pharmacologic immunosuppression.

Endoscopic-mediated, biliary hydrodynamic injection mediating clinically relevant levels of gene delivery in pig liver.

BACKGROUND AND AIMS: Gene therapy could provide curative therapies to many inherited monogenic liver diseases. Clinical trials have largely focused on adeno-associated viruses (AAVs) for liver gene delivery. These vectors, however, are limited by small packaging size, capsid immune responses, and inability to redose. As an alternative, nonviral, hydrodynamic injection through vascular routes can successfully deliver plasmid DNA (pDNA) into mouse liver but has achieved limited success in large animal models. METHODS: We explored hydrodynamic delivery of pDNA through the biliary system into the liver of pigs using ERCP and a power injector to supply hydrodynamic force. Human factor IX (hFIX), deficient in hemophilia B, was used as a model gene therapy. RESULTS: Biliary hydrodynamic injection was well tolerated without significant changes in vital signs, liver enzymes, hematology, or histology. No off-target pDNA delivery to other organs was detected by polymerase chain reaction. Immunohistochemistry revealed that 50.19% of the liver stained positive for hFIX after hydrodynamic injection at 5.5 mg pDNA, with every hepatic lobule in all liver lobes demonstrating hFIX expression. hFIX-positive hepatocytes were concentrated around the central vein, radiating outward across all 3 metabolic zones. Biliary hydrodynamic injection in pigs resulted in significantly higher transfection efficiency than mouse vascular hydrodynamic injection at matched pDNA per liver weight dose (32.7%-51.9% vs 18.9%, P < .0001). CONCLUSIONS: Biliary hydrodynamic injection using ERCP can achieve higher transfection efficiency into hepatocytes compared with AAVs at magnitudes of less cost in a clinically relevant human-sized large animal. This technology may serve as a platform for gene therapy of human liver diseases.

A hepatitis B virus transgenic mouse model with a conditional, recombinant, episomal genome.

BACKGROUND & AIMS: Development of new and more effective therapies against hepatitis B virus (HBV) is limited by the lack of suitable small animal models. The HBV transgenic mouse model containing an integrated overlength 1.3-mer construct has yielded crucial insights, but this model unfortunately lacks covalently closed circular DNA (cccDNA), the episomal HBV transcriptional template, and cannot be cured given that HBV is integrated in every cell. METHODS: To solve these 2 problems, we generated a novel transgenic mouse (HBV1.1X), which generates an excisable circular HBV genome using Cre/LoxP technology. This model possesses a HBV1.1-mer cassette knocked into the ROSA26 locus and is designed for stable expression of viral proteins from birth, like the current HBV transgenic mouse model, before genomic excision with the introduction of Cre recombinase. RESULTS: We demonstrated induction of recombinant cccDNA (rcccDNA) formation via viral or transgenic Cre expression in HBV1.1X mice, and the ability to regulate HBsAg and HBc expression with Cre in mice. Tamoxifen-inducible Cre could markedly downregulate baseline HBsAg levels from the integrated HBV genome. To demonstrate clearance of HBV from HBV1.1X mice, we administered adenovirus expressing Cre, which permanently and significantly reduced HBsAg and core antigen levels in the murine liver via rcccDNA excision and a subsequent immune response. CONCLUSIONS: The HBV1.1X model is the first Cre-regulatable HBV transgenic mouse model and should be of value to mimic chronic HBV infection, with neonatal expression and tolerance of HBV antigens, and on-demand modulation of HBV expression. LAY SUMMARY: Hepatitis B virus (HBV) can only naturally infect humans and chimpanzees. Mouse models have been developed with the HBV genome integrated into mouse chromosomes, but this prevents mice from being cured. We developed a new transgenic mouse model that allows for HBV to be excised from mouse chromosomes to form a recombinant circular DNA molecule resembling the natural circular HBV genome. HBV expression could be reduced in these mice, enabling curative therapies to be tested in this new mouse model.

Isohemagglutinin titering performed on an automated solid-phase and hemagglutinin-based analyzer is comparable to results obtained by manual gel testing.

BACKGROUND: Isohemagglutinins (anti-A and anti-B) mediate hemolytic transfusion reactions, antibody-mediated rejection of solid-organ transplants, and delayed engraftment after stem cell transplant. However, quantification of isohemagglutinins is often labor intensive and operator dependent, limiting availability and interfacility comparisons. We evaluated an automated, solid-phase and agglutination-based antibody titer platform versus manual gel testing. STUDY DESIGN AND METHODS: Plasma samples were obtained from 54 randomly selected patients. Titers were determined by our laboratory's standard assay (manual dilution followed by manual gel testing) and were compared to results obtained on a fully automated blood bank analyzer (Galileo NEO, Immucor). The analyzer determined immunoglobulin G (IgG) antibodies using solid-phase and immunoglobulin M (IgM) antibodies by direct hemagglutination. RESULTS: Isohemagglutinin titers obtained by manual gel versus the automated assay generally (>80%) agreed within one doubling dilution, and always (100%) agreed within two dilutions. Among O samples, the gel titer and the highest titer obtained with the automated assay (either IgG or IgM) were similar in paired, nonparametric analysis (p = 0.06 for anti-A; p = 0.13 for anti-B). Gel titers from group A and group B patients were slightly higher than the highest titer obtained using the automated assay (p = 0.04 for group A; p = 0.009 for group B), although these differences were within the accepted error of measurement. CONCLUSION: Manual and automated methodologies yielded similar isohemagglutinin titers. Separate quantification of IgM and IgG isohemagglutinins via automated titration may yield additional insight into hemolysis, graft survival after ABO-incompatible transplantation, and red blood cell engraftment after ABO-incompatible stem cell transplant.

Strategies for enhancing adoptive T-cell immunotherapy against solid tumors using engineered cytokine signaling and other modalities.

INTRODUCTION: Cancer therapy has been transformed by the demonstration that tumor-specific T-cells can eliminate tumor cells in a clinical setting with minimal long-term toxicity. However, significant success in the treatment of leukemia and lymphoma with T-cells using native receptors or redirected with chimeric antigen receptors (CARs) has not been recapitulated in the treatment of solid tumors. This lack of success is likely related to the paucity of costimulatory and cytokine signaling available in solid tumors, in addition to a range of inhibitory mechanisms. AREAS COVERED: We summarize the latest developments in engineered T-cell immunotherapy, describe the limitations of these approaches in treating solid tumors, and finally highlight several strategies that may be useful in mediating solid tumor responses in the future, while also ensuring safety of engineered cells. EXPERT OPINION: CAR-T therapies require further engineering to achieve their potential against solid tumors. Facilitating cytokine signaling in CAR T-cells appears to be essential in achieving better responses. However, the engineering of T-cells with potentially unchecked proliferation and potency raises the question of whether the simultaneous combination of enhancements will prove safe, necessitating continued advancements in regulating CAR-T activity at the tumor site and methods to safely switch off these engineered cells.

HBsAg-redirected T cells exhibit antiviral activity in HBV-infected human liver chimeric mice.

BACKGROUND: Chronic hepatitis B virus (HBV) infection remains incurable. Although HBsAg-specific chimeric antigen receptor (HBsAg-CAR) T cells have been generated, they have not been tested in animal models with authentic HBV infection. METHODS: We generated a novel CAR targeting HBsAg and evaluated its ability to recognize HBV+ cell lines and HBsAg particles in vitro. In vivo, we tested whether human HBsAg-CAR T cells would have efficacy against HBV-infected hepatocytes in human liver chimeric mice. RESULTS: HBsAg-CAR T cells recognized HBV-positive cell lines and HBsAg particles in vitro as judged by cytokine production. However, HBsAg-CAR T cells did not kill HBV-positive cell lines in cytotoxicity assays. Adoptive transfer of HBsAg-CAR T cells into HBV-infected humanized mice resulted in accumulation within the liver and a significant decrease in plasma HBsAg and HBV-DNA levels compared with control mice. Notably, the fraction of HBV core-positive hepatocytes among total human hepatocytes was greatly reduced after HBsAg-CAR T cell treatment, pointing to noncytopathic viral clearance. In agreement, changes in surrogate human plasma albumin levels were not significantly different between treatment and control groups. CONCLUSIONS: HBsAg-CAR T cells have anti-HBV activity in an authentic preclinical HBV infection model. Our results warrant further preclinical exploration of HBsAg-CAR T cells as immunotherapy for HBV.

In Situ Liver Expression of HBsAg/CD3-Bispecific Antibodies for HBV Immunotherapy.

Current therapies against hepatitis B virus (HBV) do not reliably cure chronic infection, necessitating new therapeutic approaches. The T cell response can clear HBV during acute infection, and the adoptive transfer of antiviral T cells during bone marrow transplantation can cure patients of chronic HBV infection. To redirect T cells to HBV-infected hepatocytes, we delivered plasmids encoding bispecific antibodies directed against the viral surface antigen (HBsAg) and CD3, expressed on almost all T cells, directly into the liver using hydrodynamic tail vein injection. We found a significant reduction in HBV-driven reporter gene expression (184-fold) in a mouse model of acute infection, which was 30-fold lower than an antibody only recognizing HBsAg. While bispecific antibodies triggered, in part, antigen-independent T cell activation, antibody production within hepatocytes was non-cytotoxic. We next tested the bispecific antibodies in a different HBV mouse model, which closely mimics the transcriptional template for HBV, covalently closed circular DNA (cccDNA). We found that the antiviral effect was noncytopathic, mediating a 495-fold reduction in HBsAg levels at day 4. At day 33, bispecific antibody-treated mice exhibited 35-fold higher host HBsAg immunoglobulin G (IgG) antibody production versus untreated groups. Thus, gene therapy with HBsAg/CD3-bispecific antibodies represents a promising therapeutic strategy for patients with HBV.

Constitutive Signaling from an Engineered IL7 Receptor Promotes Durable Tumor Elimination by Tumor-Redirected T Cells.

Successful adoptive T-cell immunotherapy of solid tumors will require improved expansion and cytotoxicity of tumor-directed T cells within tumors. Providing recombinant or transgenic cytokines may produce the desired benefits but is associated with significant toxicities, constraining clinical use. To circumvent this limitation, we constructed a constitutively signaling cytokine receptor, C7R, which potently triggers the IL7 signaling axis but is unresponsive to extracellular cytokine. This strategy augments modified T-cell function following antigen exposure, but avoids stimulating bystander lymphocytes. Coexpressing the C7R with a tumor-directed chimeric antigen receptor (CAR) increased T-cell proliferation, survival, and antitumor activity during repeated exposure to tumor cells, without T-cell dysfunction or autonomous T-cell growth. Furthermore, C7R-coexpressing CAR T cells were active against metastatic neuroblastoma and orthotopic glioblastoma xenograft models even at cell doses that had been ineffective without C7R support. C7R may thus be able to enhance antigen-specific T-cell therapies against cancer.Significance: The constitutively signaling C7R system developed here delivers potent IL7 stimulation to CAR T cells, increasing their persistence and antitumor activity against multiple preclinical tumor models, supporting its clinical development. Cancer Discov; 7(11); 1238-47. ©2017 AACR.This article is highlighted in the In This Issue feature, p. 1201.

In vivo reduction of hepatitis B virus antigenemia and viremia by antisense oligonucleotides.

BACKGROUND & AIMS: Current treatment of chronic hepatitis B virus infection (CHB) includes interferon and nucleos(t)ide analogues, which generally do not reduce HBV surface antigen (HBsAg) production, a constellation that is associated with poor prognosis of CHB. Here we evaluated the efficacy of an antisense approach using antisense oligonucleotide (ASO) technology already in clinical use for liver targeted therapy to specifically inhibit HBsAg production and viremia in a preclinical setting. METHODS: A lead ASO was identified and characterized in vitro and subsequently tested for efficacy in vivo and in vitro using HBV transgenic and hydrodynamic transfection mouse and a cell culture HBV infection model, respectively. RESULTS: ASO treatment decreased serum HBsAg levels ⩾2 logs in a dose and time-dependent manner; HBsAg decreased 2 logs in a week and returned to baseline 4 weeks after a single ASO injection. ASO treatment effectively reduced HBsAg in combination with entecavir, while the nucleoside analogue alone did not. ASO treatment has pan-genotypic antiviral activity in the hydrodynamic transfection system. Finally, cccDNA-driven HBV gene expression is ASO sensitive in HBV infected cells in vitro. CONCLUSION: Our results demonstrate in a preclinical setting the efficacy of an antisense approach against HBV by efficiently reducing serum HBsAg (as well as viremia) across different genotypes alone or in combination with standard nucleoside therapy. Since the applied antisense technology is already in clinical use, a lead compound can be rapidly validated in a clinical setting and thus, constitutes a novel therapeutic approach targeting chronic HBV infection.

Development and rescue of human familial hypercholesterolaemia in a xenograft mouse model.

Diseases of lipid metabolism are a major cause of human morbidity, but no animal model entirely recapitulates human lipoprotein metabolism. Here we develop a xenograft mouse model using hepatocytes from a patient with familial hypercholesterolaemia caused by loss-of-function mutations in the low-density lipoprotein receptor (LDLR). Like familial hypercholesterolaemia patients, our familial hypercholesterolaemia liver chimeric mice develop hypercholesterolaemia and a 'humanized' serum profile, including expression of the emerging drug targets cholesteryl ester transfer protein and apolipoprotein (a), for which no genes exist in mice. We go on to replace the missing LDLR in familial hypercholesterolaemia liver chimeric mice using an adeno-associated virus 9-based gene therapy and restore normal lipoprotein profiles after administration of a single dose. Our study marks the first time a human metabolic disease is induced in an experimental animal model by human hepatocyte transplantation and treated by gene therapy. Such xenograft platforms offer the ability to validate human experimental therapies and may foster their rapid translation into the clinic.

Clinical outcomes of hepatitis B virus coinfection in a United States cohort of hepatitis C virus-infected patients.

UNLABELLED: The effect of hepatitis B virus (HBV) coinfection in patients with hepatitis C virus (HCV) remains unclear. We used the National Veterans Affairs HCV Clinical Case Registry to identify patients with confirmed HCV viremia during 1997-2005. We defined HBV coinfection as a positive test for hepatitis B surface antigen, HBV DNA, or hepatitis B e antigen. We defined cirrhosis and hepatocellular carcinoma (HCC) based on the validated ICD-9 codes and determined mortality through the end of 2009. We performed Cox proportional hazard regression analyses to examine the effect of HBV coinfection stratified by HBV DNA status (positive or negative) on the risk of cirrhosis, HCC, and death adjusting for patients' age, gender, race, human immunodeficiency virus (HIV) infection, alcohol or drug use, Deyo Score, and antiviral treatment. Among 99,548 patients with HCV infection, 1,370 patients (1.4%) had HBV coinfection. Of the coinfected patients, 677 (49.4%) patients had at least one HBV DNA test done and 303 patients (44.7%) tested positive for HBV DNA. The incidence rates of cirrhosis, HCC, and death were significantly higher in patients with HBV coinfection and detectable HBV DNA compared to HCV monoinfection (36.8, 6.9, and 41.7 versus 17.4, 3.6, and 31.4 per 1,000 person-years, respectively; P < 0.05 for all comparisons). After adjustment for demographic, clinical, and treatment factors, patients with detectable HBV DNA had a significantly higher risk for cirrhosis (hazard ratio [HR] = 1.89 95% confidence interval [CI] = 1.46-2.45), HCC (HR = 2.12, 95% CI = 1.26-3.60), and death (HR = 1.62, 95% CI = 1.33-1.99) compared to HCV monoinfected patients. There were no differences in the risk of cirrhosis, HCC, or overall mortality between coinfected patients with undetectable HBV DNA and those with HCV monoinfection (HR = 1.18, 95% CI = 0.90-1.55; 1.54, 95% CI = 0.93-2.56; 1.08, 95% CI = 0.88-1.33, respectively). CONCLUSION: We found that while only a small number of HCV patients were coinfected with HBV, patients with documented HBV viremia were at a significantly higher risk for cirrhosis, HCC, and overall death than HCV monoinfected patients. Absence of HBV replication was associated with a clinical course similar to that of HCV monoinfected patients.

Medium-term results of total knee arthroplasty using a medially pivoting implant: a multicenter study.

A multicenter study was conducted to determine the durability and performance of a medially pivoting knee prosthesis in total knee arthroplasty (TKA). Between February 1999 and June 2001, 276 patients underwent 298 primary TKAs at five centers. There were 189 patients (204 knees) available for clinical evaluation after surgery, with an average follow-up of 5.4 years (range, 5.0-7.6 years). The mean age at follow-up was 69 years (range, 39-87 years). The posterior cruciate ligament was resected in 65% of the procedures. Knee Society scores (KSS) and radiographs were assessed for patients who returned for follow-up evaluation. Patients unwilling or unable to return were asked their status via telephone. There were a total of five revisions, and 5-year survivorship using Kaplan-Meier analysis was 97.2%. All radiographs exhibited well-fixed implants with no signs of gross migration or pending failure. Preoperative mean KSS and flexion were 33 and 107°, respectively, improving at latest follow-up to 90 and 121°, respectively. The medial-pivot prosthesis resulted in excellent survivorship with good functional results at medium-term follow-up.