Response to a Vaccination Schedule With 4 Doses of 40 μg Against Hepatitis B Virus in Cirrhotic Patients Evaluated for Liver Transplantation

We conducted a retrospective study to evaluate the response to recombinant hepatitis B vaccine after 4 intramuscular doses (40 μg) administered at 0, 1, 2, and 6 months in 157 cirrhotic patients who were liver transplant candidates. Seventeen nonresponders were revaccinated with the same schedule. We studied the association between the following variables and the vaccine response: age, gender, etiology of cirrhosis, diabetes, severity of liver disease (Child-Pugh class and Model for End-Stage Liver Disease [MELD] score), and the number of administered doses. The response rates were: 1 dose, 40% (2/5); 2 doses, 0% (0/7); 3 doses, 32.7% (16/49); and 4 doses, 31.3% (30/96) of patients. The median hepatitis B surface antibody (anti-HBs) titer was 45 mU/mL (range, 11-620 mU/mL). The response rate to revaccination was 41.2% (median anti-HBs titer, 88 mU/mL; range, 18-190 mU/mL). Diabetics showed a lower response rate than nondiabetic patients (17.2% vs 35.3%; P = .046). No association was observed between the response rate to vaccine and the other variables. In conclusion, the response rate to hepatitis B vaccine reached a little more than 30% in cirrhotic patients who received 3 or 4 doses. No higher response rate was observed among patients who received 4 doses. Diabetes was associated with a lower response rate. Anti-HBs seroconversion rates were not associated with the other variables. Revaccination may significantly increase the response rate to hepatitis B vaccine in cirrhotic patients, and may be considered in nonresponders after the third dose. Early vaccination against HBV should be considered in such patients.     

An Efficacy and Cost-Effectiveness Analysis of Combination Hepatitis B Immune Globulin and Lamivudine to Prevent Recurrent Hepatitis B After Orthotopic Liver Transplantation Compared With Hepatitis B Immune Globulin Monotherapy

Orthotopic liver transplantation (OLT) for hepatitis B virus (HBV) infection was limited until recently by poor graft and patient outcomes caused by recurrent HBV. Long-term immunoprophylaxis with hepatitis B immune globulin (HBIG) dramatically improved post-OLT survival, but recurrent HBV still occurred in up to 36% of the recipients. More recently, combination HBIG and lamivudine has been shown to effectively prevent HBV recurrence in patients post-OLT. The aim of the current study is to determine long-term outcome and cost-effectiveness of using combination HBIG and lamivudine compared with HBIG monotherapy in patients who undergo OLT for HBV. A retrospective chart review identified 59 patients administered combination HBIG and lamivudine and 12 patients administered HBIG monotherapy as primary prophylaxis against recurrent HBV. Lamivudine, 150 mg/d, was administered orally indefinitely. HBIG was administered under a standard protocol (10,000 IU intravenously during the anhepatic phase, then 10,000 IU/d intravenously for 7 days, then 10,000 IU intravenously monthly) indefinitely. A decision-analysis model was developed to evaluate the potential economic impact of prophylaxis against HBV with combination therapy compared with monotherapy. Recurrent HBV was defined as the reappearance of hepatitis B surface antigen (HBsAg) after its initial disappearance post-OLT. In the combination-therapy group, no patient redeveloped serum HBsAg or HBV DNA during mean follow-ups of 459 and 416 days, respectively. In the monotherapy group, 3 patients (25%) had reappearance of HBsAg in serum during a mean follow-up of 663 days. Combination therapy resulted in a dominant, cost-effective strategy with an average cost-effectiveness ratio of $252,111/recurrence prevented compared with $362,570/recurrence prevented in the monotherapy strategy. Combination prophylaxis with HBIG and lamivudine is highly effective in preventing recurrent HBV, may protect against the emergence of resistant mutants, and is significantly more cost-effective than HBIG monotherapy with its associated rate of recurrent HBV. (Liver Transpl 2000;6:741-748.)     

Immune Response to Persistent Staphyloccocus Aureus Periprosthetic Joint Infection in a Mouse Tibial Implant Model

Staphyloccocus aureus is one of the major pathogens in orthopedic periprosthetic joint infection (PJI), a devastating complication of total joint arthroplasty that often results in chronic and persistent infections that are refractory to antibiotics and require surgical interventions. Biofilm formation has been extensively investigated as a reason for persistent infection. The cellular composition, activation status, cytokine profile, and role of the immune response during persistent S. aureus PJI are incompletely understood. In this study, we used histology, multiparametric flow cytometry, and gene expression analysis to characterize the immune response in a clinically relevant orthopedic PJI model. We tested the hypothesis that persistent S. aureus infection induces feedback mechanisms that suppress immune cell activation, thereby affecting the course of infection. Surprisingly, persistent infection was characterized by strikingly high cytokine gene expression indicative of robust activation of multiple components of innate and adaptive immunity, along with ongoing severe neutrophil-dominated inflammation, in infected joint and bone tissues. Activation and expansion of draining lymph nodes and a bone marrow stress granulopoiesis reaction were also maintained during late phase infection. In parallel, feedback mechanisms involving T-cell inhibitory receptors and exhaustion markers, suppressive cytokines, and regulatory T cells were activated and associated with decreased T-cell proliferation and tissue infiltration during the persistent phase of infection. These results identify the cellular and molecular components of the mouse immune response to persistent S. aureus PJI and indicate that neutrophil infiltration, inflammatory cytokine responses, and ongoing lymph node and bone marrow reactions are insufficient to clear infection and that immune effector mechanisms are suppressed by feedback inhibitory pathways. These immune-suppressive mechanisms are associated with diminished T-cell proliferation and tissue infiltration and can be targeted as part of adjuvant immunotherapeutic strategies in combination with debridement of biofilm, antibiotics, and other therapeutic modalities to promote eradication of infection. © 2021 American Society for Bone and Mineral Research (ASBMR).     

Analysis of Human Biologics With a Mouse Skin Transplant Model in Humanized Mice

Preclinical testing of human therapeutic monoclonal antibodies has been limited in murine models due to species differences in pharmacokinetics and biologic responses. To overcome these constraints we developed a murine skin transplant model in humanized mice and used it to test human monoclonal antibody therapy. Neonatal NOD/SCID/IL2Rγc^null mice (NSG) were reconstituted with human CD34⁺ hematopoietic stem cells (hNSG). When adult, these mice rejected MHC mismatched murine C57BL/6J skin grafts. Rejection required adequate reconstitution with human cells. There was diffuse infiltration of the epidermis and dermis with hCD8 and hCD4 cells in rejected grafts by immunohistochemistry. Studies with B6/MHC class I and II knockout mice donors indicated that neither is required for rejection. Graft rejection was associated with the development of effector and central memory T cells and an increase in serum immunoglobulins. We also tested the effects of teplizumab (anti‐CD3 mAb) and found it could delay skin graft rejection, whereas ipilimumab (anti‐CTLA‐4 [cytotoxic T‐lymphocyte antigen‐4] mAb) treatment accelerated rejection. These findings demonstrate that hNSG mice reliably and predictably reject a xenogenic mouse skin graft by a human T cell mediated mechanism. The model can be utilized to investigate the ability of human immunotherapies to enhance or suppress functional human immune responses.     

Induction With and Without Antithymocyte Globulin Combined With Cyclosporine/Tacrolimus-Based Immunosuppression in Renal Transplantation: A Meta-analysis of Randomized Controlled Trials

Objective

The objective of this study was to conduct a meta-analysis of randomized controlled trials (RCT) to compare the effectiveness and safety of induction with and without antithymocyte globulin (ATG) combined with cyclosporine/tacrolimus-based immunosuppression in renal transplantation.

Methods

Trials were identified through a computerized literature search of PubMed, EMBASE, Cochrane controlled trials register, Cochrane Renal Group Specialized Register of RCTs, and Chinese Biomedical database. Two independent reviewers assessed trials for eligibility and quality, and then extracted data. Data were extracted for patient and graft survival, acute rejection, the incidence of Banff, cytomegalovirus (CMV) infection, leukopenia, and thrombocytopenia. Dichotomous outcomes were reported as relative risk (RR) with 95% confidence intervals (CI).

Results

Four RCTs (892 patients) were identified. The data showed that induction with ATG was more beneficial than no induction with ATG to reduce the incidence of chronic rejection (RR 0.70; 95% CI, 0.57-0.84) and acute rejection within 6 months (RR 0.68; 95% CI, 0.49-0.96) and at 12 months (RR 0.67; 95% CI, 0.50-0.89) as well as Banff II episodes (RR 0.53; 95% CI, 0.30-0.91), but increased the incidences of CMV infection (RR 1.61; 95% CI, 1.27-2.04) and leukopenia (RR 3.88; 95% CI, 2.80-5.38) and thrombocytopenia (RR 2.92; 95% CI, 1.77-4.04). There was no statistical difference between patient or graft survival rates at 6 and 12 months, as well as the incidences of Banff III or Banff I after transplantation.

Conclusion

Based on available data induction with ATG was more efficient to reduce the rate of acute rejection episodes and chronic rejection responses after renal transplantation, but was associated with increased side effects, particularly CMV infections. It is important to provide the most benefit for an individual patient.     

Exogenous Lipocalin 2 Ameliorates Acute Rejection in a Mouse Model of Renal Transplantation

Lipocalin 2 (Lcn2) is rapidly produced by damaged nephron epithelia and is one of the most promising new markers of renal injury, delayed graft function and acute allograft rejection (AR); however, the functional importance of Lcn2 in renal transplantation is largely unknown. To understand the role of Lcn2 in renal AR, kidneys from Balb/c mice were transplanted into C57Bl/6 mice and vice versa and analyzed for morphological and physiological outcomes of AR at posttransplantation days 3, 5, and 7. The allografts showed a steady increase in intensity of interstitial infiltration, tubulitis and periarterial aggregation of lymphocytes associated with a substantial elevation in serum levels of creatinine, urea and Lcn2. Perioperative administration of recombinant Lcn2:siderophore:Fe complex (rLcn2) to recipients resulted in functional and morphological amelioration of the allograft at day 7 almost as efficiently as daily immunosuppression with cyclosporine A (CsA). No significant differences were observed in various donor–recipient combinations (C57Bl/6 wild‐type and Lcn2^?/?, Balb/c donors and recipients). Histochemical analyses of the allografts showed reduced cell death in recipients treated with rLcn2 or CsA. These results demonstrate that Lcn2 plays an important role in reducing the extent of kidney AR and indicate the therapeutic potential of Lcn2 in transplantation.

     

Response to Allopurinol Pretreatment in a Swine Model of Heart-Lung Transplantation

The role of allopurinol in the prevention of ischemia-reperfusion injury was assessed in a model of heart-lung transplantation. Fourteen swine were divided into two groups (seven donors and seven recipients). All heart and lung blocks were placed in hypothermic storage after perfusion with cold iso-osmolar cardioplegic solution and modified Collins solution, respectively (t = 8–10°C for heart and t = 16–18°C for lungs). The total ischemic time including the orthotopic transplantation was 6 h. Animals (donors and recipients) were pretreated with allopurinol given orally at a dosage of 50 mg/kg for 4 days. Animals were assessed by monitoring heart and lung function, including extravascular lung water at three time intervals, which included pretransplantation (donor), and 30 min and 2 h posttransplantation (recipient). Erythrocyte peroxidation susceptibility was assessed for 3 days, and surgery was performed on day 4. The malondialdehyde levels determined from erythrocyte exposure to in vitro peroxidative challenge classified three paired donor and recipient animals as responders and four paired donor and recipient animals as nonresponders to the allopurinol pretreatment. A persistent deterioration of lung function was observed over time in nonresponders (p > 05) (increase of lung water, decrease of partial pressure of oxygen, increase in alveolar-arterial gradient, and decrease in arterial-alveolar tension ratio). Responders showed no significant alterations in lung function. This study in swine, a species devoid of myocardial xanthine oxidase activity, indicates that allopurinol may have a mechanism of action other than xanthine oxidase inhibition in the prevention of ischemia-reperfusion injury. The parallelism between protection of lung function and of red blood cells suggests the involvement of a generalized increase in tissue antioxidant capacity.     

Predictive Factors of Lack of Response to Antiviral Therapy Among in Patients With Recurrent Hepatitis C After Liver Transplantation

The current therapy for hepatitis C recurrence after liver transplantation OLT is based on interferon (IFN) and ribavirin (RBV) in monotherapy or combination. The rate of sustained virological response (SVR) varies between 10% and 45%. We have retrospectively analyzed factors that could predict SVR after antiviral therapy. We analyzed 42 patients who completed a cycle of therapy with natural or pegylated IFN plus RBV. There were 15 (35.7%) patients who obtained an SVR. The following factors were significantly associated with a lack of SVR: donor age ≥50 years (P = .046); donor body mass index (BMI) > 27 (P = .016); genotype 1 versus 2 to 3 (P = 0.010), aspartate transferase (AST) before therapy ≥ 140 U/L (P = .046), alanine transferase before therapy ≥ 280 U/L (P = .055), use of natural IFN versus pegylated IFN (P = .016). The only factors remaining after multivariate analysis were: donor BMI, AST before therapy and genotype. Our data confirmed that genotype 1 was associated with poorer outcomes; other additional parameters can influence the response to antiviral therapy.     

LIGHT/HVEM/LTβR Interaction as a Target for the Modulation of the Allogeneic Immune Response in Transplantation

The exchange of information during interactions of T cells with dendritic cells, B cells or other T cells regulates the course of T, B and DC‐cell activation and their differentiation into effector cells. The tumor necrosis factor superfamily member LIGHT (homologous to lymphotoxin, exhibits inducible expression and competes with HSV glycoprotein D for binding to herpesvirus entry mediator, a receptor expressed on T lymphocytes) is transiently expressed upon T cell activation and modulates CD8 T cell‐mediated alloreactive responses upon herpes virus entry mediator (HVEM) and lymphotoxin β receptor (LTβR) engagement. LIGHT‐deficient mice, or WT mice treated with LIGHT‐targeting decoy receptors HVEM‐Ig, LTβR‐Ig or sDcR3‐Ig, exhibit prolonged graft survival compared to untreated controls, suggesting that LIGHT modulates the course and severity of graft rejection. Therefore, targeting the interaction of LIGHT with HVEM and/or LTβR using recombinant soluble decoy receptors or monoclonal antibodies represent an innovative therapeutic strategy for the prevention and treatment of allograft rejection and for the promotion of donor‐specific tolerance.     

TLR9 Deficiency in B Cells Promotes Immune Tolerance via Interleukin-10 in a Type 1 Diabetes Mouse Model

Toll-like receptor 9 (TLR9) is highly expressed in B cells, and B cells are important in the pathogenesis of type 1 diabetes (T1D) development. However, the intrinsic effect of TLR9 in B cells on β-cell autoimmunity is not known. To fill this knowledge gap, we generated NOD mice with a B-cell–specific deficiency of TLR9 (TLR9^fl/fl/CD19-Cre+ NOD). The B-cell–specific deletion of TLR9 resulted in near-complete protection from T1D development. Diabetes protection was accompanied by an increased proportion of interleukin-10 (IL-10)–producing B cells. We also found that TLR9-deficient B cells were hyporesponsive to both innate and adaptive immune stimuli. This suggested that TLR9 in B cells modulates T1D susceptibility in NOD mice by changing the frequency and function of IL-10–producing B cells. Molecular analysis revealed a network of TLR9 with matrix metalloproteinases, tissue inhibitor of metalloproteinase-1, and CD40, all of which are interconnected with IL-10. Our study has highlighted an important connection of an innate immune molecule in B cells to the immunopathogenesis of T1D. Thus, targeting the TLR9 pathway, specifically in B cells, may provide a novel therapeutic strategy for T1D treatment.     

Increased Risk of Severe Hepatitis C Virus Recurrence After Liver Transplantation in Patients With a T Allele of IL28B rs12979860

BACKGROUND: Polymorphisms of the IL28B gene (encoding interferon-λ3) determine the spontaneous course of hepatitis C virus (HCV) infection and its response to antiviral therapy. We investigated the influence of the IL28B rs12979860 (C>T) polymorphism on the risk of severe HCV recurrence after liver transplantation. METHODS: Ninety patients who underwent transplantation because of HCV cirrhosis were retrospectively analyzed; forty-one (45.6%) of them with severe HCV recurrence. Forty-eight of their paired donors were available and were also analyzed. IL28B rs12979860 was genotyped by real-time polymerase chain reaction, and evaluated for association with severe HCV recurrence, along with other variables, by univariate and multivariate analyses. RESULTS: The risk allele rs12979860-T was more common in transplanted patients (66.7%) than reported in healthy whites, and it was significantly overrepresented among patients with severe HCV recurrence, in comparison with patients without it (82.9% vs. 53.1%, odds ratio [OR]=4.30, etiologic fraction=63.6%; P=0.0028). Furthermore, separate analysis of the recipients' genotypes indicated that the risk of severe HCV recurrence increased with the dose of the T allele (linear trend, P=0.0068). Multiple logistic regression analysis confirmed the contribution of the IL28B genotype to the risk of severe HCV recurrence (OR=4.27; P=0.014), independently of other associated factors. Allele IL28B T in the donor seemed to have an opposite effect than that in the recipient (OR=0.46), but the study was underpowered to demonstrate this unforeseen effect (P=0.1995). CONCLUSIONS: The recipient IL28B rs12979860 genotype has a major influence on the posttransplantation course of HCV infection, being a valuable biomarker for patient care in liver transplantation.     

The HIF-PHI BAY 85-3934 (Molidustat) Improves Anemia and Is Associated With Reduced Levels of Circulating FGF23 in a CKD Mouse Model

Fibroblast growth factor-23 (FGF23) is a critical factor in chronic kidney disease (CKD), with elevated levels causing alterations in mineral metabolism and increased odds for mortality. Patients with CKD develop anemia as the kidneys progressively lose the ability to produce erythropoietin (EPO). Anemia is a potent driver of FGF23 secretion; therefore, a hypoxia-inducible factor prolyl hydroxylase inhibitor (HIF-PHI) currently in clinical trials to elevate endogenous EPO to resolve anemia was tested for effects on iron utilization and FGF23-related parameters in a CKD mouse model. Mice were fed either a casein control diet or an adenine-containing diet to induce CKD. The CKD mice had markedly elevated iFGF23 and blood urea nitrogen (BUN), hyperphosphatemia, and anemia. Cohorts of mice were then treated with a patient-equivalent dose of BAY 85-3934 (BAY; Molidustat), which elevated EPO and completely resolved aberrant complete blood counts (CBCs) in the CKD mice. iFGF23 was elevated in vehicle-treated CKD mice (120-fold), whereas circulating iFGF23 was significantly attenuated (>60%) in the BAY-treated CKD mice. The BAY-treated mice with CKD also had reduced BUN, but there was no effect on renal vitamin D metabolic enzyme expression. Consistent with increased EPO, bone marrow Erfe, Transferrin receptor (Tfrc), and EpoR mRNAs were increased in BAY-treated CKD mice, and in vitro hypoxic marrow cultures increased FGF23 with direct EPO treatment. Liver Bmp-6 and hepcidin expression were downregulated in all BAY-treated groups. Femur trabecular parameters and cortical porosity were not worsened with BAY administration. In vitro, differentiated osteocyte-like cells exposed to an iron chelator to simulate iron depletion/hypoxia increased FGF23; repletion with holo-transferrin completely suppressed FGF23 and normalized Tfrc1. Collectively, these results support that resolving anemia using a HIF-PHI during CKD was associated with lower BUN and reduced FGF23, potentially through direct restoration of iron utilization, thus providing modifiable outcomes beyond improving anemia for this patient population. © 2021 American Society for Bone and Mineral Research (ASBMR).     

Reactivation of Hepatitis B Virus Infection With Reverse Seroconversion Following Umbilical Cord Allogeneic Hematopoietic Cell Transplantation in a Hepatitis-B-Immune Patient: A Case Report

Hepatitis B virus (HBV) reactivation in patients with prior exposure to HBV and protective levels of hepatitis B surface antibody (HBsAb) is a rare phenomenon and is termed reverse seroconversion. We describe a case of reactivation of HBV infection following reverse seroconversion in a patient who underwent umbilical cord allogeneic hematopoietic cell transplantation (UHCT). The patient developed acute hepatitis with positive hepatitis B surface antigen (HBsAg) and HBV DNA in the context of prior strongly positive HBsAb. The patient was treated with oral tenofovir and liver function tests returned to normal 3 months later. Long-term monitoring for HBV reactivation should be considered in patients with prior exposure to HBV undergoing UHCT regardless of HBsAb status.     

Overexpression of Fibrinogen‐Like Protein 2 Promotes Tolerance in a Fully Mismatched Murine Model of Heart Transplantation

Fibrinogen‐like protein 2 (FGL2) is an immunomodulatory protein that is expressed by regulatory T cells (Tregs). The objective of this study was to determine if recombinant FGL2 (rFGL2) treatment or constitutive FGL2 overexpression could promote transplant tolerance in mice. Although rFGL2 treatment prevented rejection of fully mismatched cardiac allografts, all grafts were rejected after stopping treatment. Next, we generated FGL2 transgenic mice (fgl2^Tg) that ubiquitously overexpressed FGL2. These mice developed normally and had no evidence of the autoimmune glomerulonephritis seen in fgl2^?/? mice. Immune characterization showed fgl2^Tg T cells were hypoproliferative to stimulation with alloantigens or anti‐CD3 and anti‐CD28 stimulation, and fgl2^Tg Tregs had increased immunosuppressive activity compared with fgl2^+/+ Tregs. To determine if FGL2 overexpression can promote tolerance, we transplanted fully mismatched cardiac allografts into fgl2^Tg recipients. Fifty percent of cardiac grafts were accepted indefinitely in fgl2^Tg recipients without any immunosuppression. Tolerant fgl2^Tg grafts had increased numbers and proportions of Tregs and tolerant fgl2^Tg mice had reduced proliferation to donor but not third party antigens. These data show that tolerance in fgl2^Tg recipients involves changes in Treg and T cell activity that contribute to a higher intragraft Treg–to–T cell ratio and acceptance of fully mismatched allografts.     

Inflammatory Response to Implant Particulates in a Macrophage/Osteoblast Coculture Model

The purpose of this study was to further define the cellular response to titanium and polymethylmethacrylate (PMMA) particles in aseptic loosening, and to determine if the use of pamidronate may be effective in inhibiting bone resorption associated with this response. Macrophages and osteoblasts were cocultured to simulate the environment around an aseptically loose prosthesis. Macrophages were plated on the bottom of six well plates and osteoblasts were plated on culture dish inserts, and placed into the wells with the macrophages. Incubation of macrophages with PMMA in this system led to release of prostaglandin E (PGE₂), granulocyte macrophage-colony stimulating factor (GM-CSF), and interleukin-6 (IL-6). Incubation with titanium led to release of tumor necrosis factor (TNF) and IL-6. Exposure of calvaria to media from cells exposed to either PMMA or titanium led to release of calcium 45. Incubation of calvaria with pamidronate was able to inhibit release of calcium 45 associated with exposure to the macrophage/osteoblast/particle conditioned medium. Bone resorption at the interface between implant and bone is a consistent feature leading to loosening of orthopedic implants. By inhibiting bone resorption associated with the inflammatory response to implant particulates, pamidronate or other bisphosphonates may have clinical utility in the treatment or prevention or aseptic loosening. Received: 22 December 1995 / Accepted: 3 May 1996     

Cyclosporine Does Not Prevent Microvascular Loss in Transplantation but Can Synergize With a Neutrophil Elastase Inhibitor,Elafin, to Maintain Graft Perfusion During Acute Rejection

The loss of a functional microvascular bed in rejecting solid organ transplants is correlated with fibrotic remodeling and chronic rejection; in lung allografts, this pathology is predicted by bronchoalveolar fluid neutrophilia which suggests a role for polymorphonuclear cells in microcirculatory injury. In a mouse orthotopic tracheal transplant model, cyclosporine, which primarily inhibits T cells, failed as a monotherapy for preventing microvessel rejection and graft ischemia. To target neutrophil action that may be contributing to vascular injury, we examined the effect of a neutrophil elastase inhibitor, elafin, on the microvascular health of transplant tissue. We showed that elafin monotherapy prolonged microvascular perfusion and enhanced tissue oxygenation while diminishing the infiltration of neutrophils and macrophages and decreasing tissue deposition of complement C3 and the membrane attack complex, C5b‐9. Elafin was also found to promote angiogenesis through activation of the extracellular signal‐regulated kinase (ERK) signaling pathway but was insufficient as a single agent to completely prevent tissue ischemia during acute rejection episodes. However, when combined with cyclosporine, elafin effectively preserved airway microvascular perfusion and oxygenation. The therapeutic strategy of targeting neutrophil elastase activity alongside standard immunosuppression during acute rejection episodes may be an effective approach for preventing the development of irreversible fibrotic remodeling.