Immune Prophylaxis Research Articles

Antibody Prophylaxis Against Dengue Virus 2 Infection in Non-Human Primates.

Passive immunization with anti-dengue virus (DENV) immune serum globulin (ISG) or monoclonal antibodies (Mabs) may serve to supplement or replace vaccination for short-term dengue immune prophylaxis. In the present study, we sought to establish proof-of-concept by evaluating several DENV-neutralizing antibodies for their ability to protect rhesus macaques against viremia following live virus challenge, including human anti-dengue ISG, and a human Mab (Mab11/wt) and its genetically engineered variant (Mab11/mutFc) that is unable to bind to cells with Fc gamma receptors (FcγR) and potentiate antibody-dependent enhancement (ADE). In the first experiment, groups of animals received ISG or Mab11/wt at low doses (3-10 mg/kg) or a saline control followed by challenge with DENV-2 at day 10 or 30. After passive immunization, only low-titered circulating virus-neutralizing antibody titers were measured in both groups, which were undetectable by day 30. After challenge at day 10, a reduction in viremia duration compared with the control was seen only in the ISG group (75%). However, after a day 30 challenge, no reduction in viremia was observed in both immunized groups. In a second experiment to test the effect of higher antibody doses on short-term protection, groups received either ISG, Mab11/wt, Mab11/mutFc (each at 25 mg/kg) or saline followed by challenge with DENV-2 on day 10. Increased virus-neutralizing antibody titers were detected in all groups at day 5 postinjection, with geometric mean titers (GMTs) of 464 (ISG), 313 (Mab11/wt), and 309 (Mab11/mutFc). After challenge, there was complete protection against viremia in the group that received ISG, and a reduction in viremia duration of 89% and 83% in groups that received Mab11/wt and Mab11/mutFc, respectively. An in vitro ADE assay in Fcγ receptor-bearing K562 cells with sera collected immediately before challenge showed increased DENV-2 infection levels in the presence of both ISG and Mab11/wt, which peaked at a serum dilution of 1:90, but not in Mab11/mutFc containing sera. The results suggest that antibody prophylaxis for dengue might be beneficial in eliminating or reducing viral loads thereby minimizing disease progression. Our results also suggest that blocking FcγR interactions through Mab11 Fc engineering may further prevent ADE.

Human embryonic stem cell-derived mesenchymal stromal cells ameliorate collagen-induced arthritis by inducing host-derived indoleamine 2,3 dioxygenase

BackgroundThe immunosuppressive and anti-inflammatory properties of mesenchymal stromal cells (MSC) have prompted their therapeutic application in several autoimmune diseases, including rheumatoid arthritis. Adult MSC are finite and their clinical use is restricted by the need for long-term expansion protocols that can lead to genomic instability. Inhibition of Smad2/3 signaling in human pluripotent stem cells (hPSC) provides an infinite source of MSC that match the phenotype and functional properties of adult MSC. Here, we test the therapeutic potential of hPSC-MSC of embryonic origin (embryonic stem cell-derived mesenchymal stromal cells, hESC-MSC) in the experimental model of collagen-induced arthritis (CIA).MethodsCIA was induced in DBA/1 mice by immunization with type II collagen (CII) in Complete Freund’s Adjuvant (CFA). Mice were treated with either a single dose (106 cells/mouse) of hESC-MSC on the day of immunization (prophylaxis) or with three doses of hESC-MSC every other day starting on the day of arthritis onset (therapy). Arthritis severity was evaluated daily for six weeks and ten days, respectively. Frequency of Treg (FoxP3+), Th1 (IFNγ+) and Th17 (IL17+) CD4+ T cells in inguinal lymph nodes (ILN) was quantified by flow cytometry. Serum levels of anti-CII antibodies were determined by ELISA. Detection of hESC-MSC and quantification of murine and human indoleamine 2,3 dioxygenase (IDO1) expression was performed by quantitative real-time PCR. Statistical differences were analyzed by ANOVA and the Mann-Whitney U test.ResultsAdministration of hESC-MSC to mice with established arthritis reduced disease severity compared to control-treated mice. Analysis of CD4 T cell populations in treated mice showed an increase in FoxP3+ Treg and IFNγ+ Th1 cells but not in Th17 cells in the ILN. Anti-CII antibody levels were not affected by treatment. Migration of hESC-MSC to the ILN in treated mice was associated with the induction of murine IDO1.ConclusionTreatment with hESC-MSC ameliorates CIA by inducing IFNγ+ Th1 cells and IDO1 in the host. Thus, hESC-MSC can provide an infinite cellular source for treatment of rheumatoid arthritis.

Prevalence of Rhesus D-negative blood type and the challenges of Rhesus D immunoprophylaxis among obstetric population in Ogbomoso, Southwestern Nigeria

Background: Rhesus incompatibility could pose a major problem in pregnancy, and it could be the cause of obstetric failure in a handful of women. Implementation of programs for antenatal and postnatal (Rhesus D) RhD immune globulin prophylaxis has led to a significant reduction in the frequency of maternal RhD alloimmunization and associated fetal and neonatal complications. Aims: To determine the prevalence of RhD negative among the pregnant population attending the antenatal clinic of a young tertiary health institution in Ogbomoso, a semi-urban town in southwestern Nigeria, and also the challenges faced by this sub-population of pregnant women. Materials and Methods: A retrospective review of the antenatal and labour records of obstetric patient attending Ladoke Akintola University of Technology Teaching Hospital (LTH), Ogbomoso, Nigeria. Variables were expressed as percentages. Result: Of the 596 booked patient who had their blood group systems determined, 563 women (94.5%) were RhD-positive, and 33(5.5%) women were RhD-negative. Almost 50% of the Rh-negative pregnant women were primipara. Twenty-three (69.7%) of the study population had a previous delivery or abortion, but only 9 (39.1%) of these had the Rhesus anti-D immunoglobulin following the delivery or the abortion. One of the RhD-negative women had been sensitized to the RhD positive antigen from the previous delivery at the time of booking the index pregnancy. Of the study population that delivered in our facility, only 11 (33.3%) received the anti-D immunoglobulin after the delivery, and financial inability to purchase the anti-D immunoglobulin was a major reason for refusing the immunoprophylaxis. Conclusion: Although the prevalence of RhD negative still remains low, and the rate of Rh-immunoprophylaxis remains quite low in our obstetric population, the risk of haemolytic disease of the newborn with its attendant perinatal morbidity and mortality is real in our community. The anti-D immunoglobulin should be made available and affordable.

Comprehensive review of telbivudine in pregnant women with chronic hepatitis B.

To achieve an evidence-based conclusion regarding the safety and efficacy of telbivudine during pregnancy. A pooled analysis of data from a literature search reported 1739 pregnancy outcomes (1673 live births) from 1725 non-overlapping pregnant women treated with telbivudine. The prevalence of live birth defects (3.6/1000) was similar to that of the non-antiviral controls (3.0/1000) and not increased as compared with overall prevalence (14.5 to 60/1000). No target organ toxicity was identified. The prevalence of spontaneous abortion in pregnant women treated with telbivudine (4.2/1000) was not increased compared with the overall prevalence (16/1000). The mother-to-child transmission rate was significantly reduced in pregnant women treated with telbivudine (0.70%) compared to those treated with the non-antiviral controls (11.9%; P < 0.0001) or compared to the historical rates of hepatitis B virus (HBV)-infected population without antiviral treatment (10%-15%). Cumulatively 489 pregnancy cases have been reported in the telbivudine pharmacovigilance database (with a cut-off date 31 August 2014), of those, 308 had known pregnancy outcomes with 249 cases of live births (239 cases of live birth without congenital anomaly and 10 cases of live birth with congenital anomaly). In the latest antiretroviral pregnancy registry report (1 January 1989 through 31 January 2015) of 27 patients exposed to telbivudine during pregnancy (18, 6 and 3 during first, second and third trimester, respectively) 19 live births were reported and there were no cases of birth defects reported. Telbivudine treatment during pregnancy presents a favorable safety profile without increased rates of live birth defects, spontaneous abortion or elective termination, or fetal/neonatal toxicity. Exposure to telbivudine in the first, second and third trimester of pregnancy has been shown to significantly reduce the risk of HBV transmission from mother to child on the basis of standard immune prophylaxis procedure.

The Functional Distance Between Mismatched HLA-DPB1 Increases Risks of Relapse and Mortality after Unrelated Donor Hematopoietic Cell Transplantation for AML, ALL and MDS: A Refinement of the T Cell Epitope Group Algorithm for Permissive Mismatches

Background: We and others have previously shown that non-permissive T cell epitope (TCE) group mismatches at HLA-DPB1 are associated with the risks of mortality after hematopoietic cell transplantation (HCT) from 10/10 HLA-matched unrelated donors (Fleischhauer et al, Lancet Oncol 2012; Pidala et al, Blood 2014). Moreover, we recently reported that TCE groups are reflected by a numerical score assignable to each HLA-DPB1 allele based on the combined median impact of 12 naturally occurring amino acid substitutions (AAS) on allorecognition of HLA-DPB1*09:01 as reference, termed functional distance (FD) (Crivello et al, Biol Blood Marrow Transplant 2015). Here we studied the association between the Delta in FD scores of HLA-DPB1 alleles present in the patient and in the donor (Delta-FD), and the clinical outcome of unrelated HCT.Methods: 417 consecutive adult patients transplanted from a 10/10 HLA-matched unrelated donor AML (n=302 [72%]), ALL (n=58 [8%]), or MDS (n=57 [14%]) at the University Hospital Essen between the years 2005 and 2014 were included in the analysis. 37 pairs were matched for both HLA-DPB1 alleles (12/12 HLA matches) while the remaining 380 pairs were HLA-DPB1 mismatched. Among the latter, Delta-FD scores were calculated as the absolute number of [FDpatient-FDdonor] on the basis of previously described FD scores for each HLA-DPB1 allele (Crivello et al, Biol Blood Marrow Transplant 2015).Results: The median Delta-FD score of HLA-DPB1 mismatched pairs was 1.64 (0.01-7.46). Receiver Operator Curves indicated stratification into 2 subgroups with Delta-FD scores <=2.665 (n=253 [66%]) and >2.665 (n=127 [34%]) as the best predictor of overall survival (OS). The 2 subgroups showed no significant differences for the distribution of major variables including diagnosis, disease status at transplant, immune prophylaxis and conditioning regimen, except for the percentage of permissive HLA-DPB1 TCE mismatches which was significantly higher in the subgroup with Delta-FD scores <=2.665 (p<0.0001).With a median follow-up of 4 yrs for surviving pts, the 5-yrs OS in the entire HLA-DPB1 mismatched cohort was 48%. In the 2 Delta-FD subgroups, the Kaplan-Meier (KM) probabilities of OS were 52% for Delta-FD <=2.665 and 38% for Delta-FD >2.665 (p<0.008), compared to 50% and 44% (p=0.31) for permissive and non-permissive TCE mismatches, respectively. In multivariate analysis, independent predictors of OS were time-dependent acute GvHD (HR 3.41, p<0.0001) and chronic GvHD (HR 0.41, p<0.0001), the use of anti-thymocyte globulin (HR 0.58, p=0.0006), disease status at transplant (HR 1.27, p<0.007), patient age (HR 1.63 p<0.007), and the stratified Delta-FD score (HR 1.51, p<0.007). Moreover, Delta-FD scores >2.665 were associated with lower probability of event-free survival (HR 1.48, p<0.007), due to significantly higher risks of disease relapse (HR 1.52, p<0.03) and NRM (HR 1.50, p<0.045), but not of acute or chronic GvHD. No significant differences were observed for any of the endpoints between 12/12 HLA-matched and 10/10 HLA-matched pairs with Delta-FD <=2.665.Conclusion: Stratification of HLA-DPB1 mismatches according to Delta-FD scores between donor and recipient represents a refinement of our previously published TCE algorithm of non-permissive mismatches with significant overlaps. In comparison to the latter, Delta-FD scores showed improved associations with the risks of mortality and relapse after 10/10 HLA-matched unrelated HCT in the patient cohort analyzed. If confirmed, these findings could provide a refined tool for donor-recipient matching for HLA-DPB1, and suggest that the combined impact of key AAS on T-cell alloreactivity, rather than AAS at individual positions, are relevant parameters for risk prediction in HLA-DPB1 mismatched HCT. DisclosuresNo relevant conflicts of interest to declare.

New broadly reactive neutralizing antibodies against hepatitis B virus surface antigen

Hepatitis B virus (HBV) surface antigen (HBsAg) is considered to be the most important target for the diagnosis and immune prophylaxis of HBV infection. HBsAg-specific monoclonal antibodies (MAbs) are extensively used for studying the complex structure of the HBsAg, mapping the neutralizing epitopes and development of HBV diagnostic tests. However, the efficiency of anti-HBV binding strongly depends on the epitope structure and MAb capability to recognize different HBV variants. In the current study, 9 MAbs against yeast-expressed HBsAg of ayw2 serotype were generated and 7 of them were shown to recognize a linear epitope comprising amino acid (aa) residues 119-GPCRTCT-125 within the main antigenic “a” determinant of HBsAg. One MAb of the highest affinity (clone HB1) was selected for detailed cross-reactivity studies, generation of recombinant single-chain antibody (scFv) and molecular modelling of antibody-epitope interaction. The importance of each aa residue within the identified MAb epitope was determined by alanine substitution study that revealed aa residues C(121), T(123), C(124) and T(125) as essential for binding. These aa residues are highly conserved among HBV variants. In contrast, alanine substitution of G119, P120 and R122 had no or minor influence on the reactivity with the MAb. Certain aa residues at position 122 (either R or K) define different HBV serotypes (either d or y), therefore, the affinity of the MAb HB1 for the epitope with R122K substitution was determined to evaluate its diagnostic potential. The MAb recognized both epitope variants with high affinity. Sequence alignment of the MAb epitope within different HBV strains demonstrated that the shortest peptide recognized by the MAb 121-CR(K)TCT-125 is identical among different human HBV genotypes (HBV A-F, H) and monkey HBV species (HBVCP, HBVGO, HBVGB, WMHBV). In line with these data, the MAb HB1 was cross-reactive in Western blot with a large panel of antigens derived from different HBV genotypes. Recombinant scFv consisting of immunoglobulin VH and VL regions joined by a 20 aa-long linker was generated by cloning the respective cDNA sequences from hybridoma HB1. The recombinant scFv generated in Escherichia coli recognized the same epitope as the parental MAb HB1. Cloning of HB1 VH and VL regions allowed determination of their primary structure and subsequent computer modeling of antibody–epitope interaction. The generated molecular models of HB1 variable region with its target peptides were in accordance with experimental data showing the importance of certain aa residues in antibody binding. In conclusion, the current study describes new HBsAg-specific antibodies with HBV-neutralizing potency and a broad cross-reactivity against different HBV strains. The generated MAb HB1 will be of great value in diagnostic and research settings, while the recombinant HB1-derived scFv represents a promising “building block” for producing anti-HBV tools with a potential biopharmaceutical application.

The Diagnosis and Treatment of Optic Neuritis

Typical optic neuritis is often the presenting manifestation of multiple sclerosis (MS). Its incidence in central Europe is 5 cases per 100 000 persons per year. This review is based on articles retrieved by a selective search of the PubMed database, on the pertinent guidelines, and on the authors' clinical experience. The diagnosis of optic neuritis is based on a constellation of symptoms and signs. The onset is usually with pain on eye movement in one eye and subacute visual loss. In unilateral optic neuritis, the direct pupillary light reflex is weaker in the affected eye. One-third of patients with optic neuritis have a mildly edematous optic disc. The visual disturbance resolves in 95% of cases. A less favorable course may be evidence of neuromyelitis optica, and macular involvement may be evidence of neuroretinitis. High-dosed intravenous methylprednisolone therapy speeds recovery but does not improve the final outcome. The risk that a patient with optic neuritis will later develop multiple sclerosis can be assessed with an MRI scan of the brain. Optic neuritis is easy to distinguish from otherv diseases affecting the optic nerve. Atypical forms of this disease and other optic nerve diseases require special treatment. For patients judged to be at high risk of developing multiple sclerosis, immune prophylaxis with beta- interferon or glatiramer acetate is recommended.

Immunogenic Activity of Secreted Protein-Based Compounds Staphylococcus aureus № 6

Difficulties in the therapy of infection, caused by S. aureus, depends on the resistance of staphylococci to antibiotics, proceeding to chronicity of the diseases and the development on that background the depression of innate immunity functions and decreasing of the host resistance to the infection. In spite of tremendous efforts of researchers, up to date there are no commercial antistaphylococcal vaccine the efficacy of which would be proved in the completed clinical trials. Aim: obtaining secreted protein-based substances of the S. aureus № 6 and investigation their immunogenicity. Material and methods. Secreted protein-based substances (SPS) were obtain as: «initial» – from the filtrates of the culture fluid of the S. aureus № 6, grown to the end of the exponential phase according to the technology described previously [9], and I SPS and II SPS – after the ion-exchange chromatography of the «initial» SPS on the columns with Q-Sepharose and DEAE-Sepharose. The level of specific IgG antibodies in sera of immunized rabbits and mice determined in ELISA, the immunogenic activity evaluated in experiments of active and passive protection from the challenge performed on BALB/с mice and also by the determination of the bacterial content in organs and in the test of abscesses formation in kidneys. Results. Investigated SBS possessed the antigenic activity (the level of specific IgG antibodies in sera of immunized animals increased 2.2 – 7.5 times compared to the control groups), that is favor of the activation of the adaptive immunity system and significant protective activity revealed in experiments of active (index of efficacy 2.63 – 4.28) and passive protection. The immunization of mice with the «initial» and II SPS led to significant decrease of the number of colonyforming units of S. aureus and formation of abscesses in kidneys of mice. It is evidently, that investigated SPS, influence on the severity of staphylococcal infection and possesses the therapeutic effect. Conclusion. The preformed complex analysis at the current stage allowed to reveal perspectives of the further study of «initial» and II SPS in pre-clinical trials, as candidates, possessing the high protective facilities, for including them in the drug composition for immune prophylaxis and immunotherapy of diseases, caused by S. aureus.

Anti‐D alloimmunisation in pregnant women with DEL phenotype in China

To analyse anti-D alloimmunisation in pregnant women with D-elute (DEL) phenotype in China, for developing a predictive model to evaluate whether a person with the DEL phenotype can receive RhD-positive blood. Alloanti-D acquired by pregnancy or transfusion is one of the major causes of both haemolytic disease among newborns and haemolytic transfusion reactions. To date, there is little data available about the antigenic properties and immunogenicity of extremely weak D variants known as DEL. RHD genotyping and D epitope mapping were performed using gene sequencing and comprehensive immunohaematological methods, respectively. DEL pregnant women carrying an RhD-positive fetus were tested for the presence of alloanti-D. A total of 130 of 142 (91·5%) pregnant women with a DEL phenotype were confirmed to carry the RHD (K409K) allele. Among 12 DEL women who appeared to have RHD-CE-D hybrid alleles, there were 1 RHD-CE (4-7)-D, 7 RHD-CE(4-9)-D, and 4 RHD-CE (2-5)-D alleles. Alloanti-D antibodies were detected in 6 of 142 DEL women, and all the six women had the partial DEL phenotype. The data indicate that partial DEL women appear at risk of alloimmunization to the D antigen. RhD immune globulin prophylaxis is necessary for partial DEL women. Partial DEL patients should receive only RhD-negative RBCs, whereas DEL patients with complete expression of antigen can safely receive RhD-positive RBCs.

Characterization of Tunga penetrans antigens in selected epidemic areas in Murang'a county in Kenya.

Tunga penetrans are fleas that cause tungiasis, a condition characterized by high transmission rate due to poor housing conditions, social neglect and inadequate health care in economically disadvantaged communities in developing countries. This study therefore aimed at characterizing jiggers antigens to identify immunodominant ones to help understand immunological behavior of the parasite that would otherwise be important in future control of the parasite. Samples were gravid fleas and blood samples from infested individuals in Kahuro and Murang’a East district in Murang’a County. Freeze and thaw was used to extract soluble proteins from the fleas. Ouchterlony Double immunodiffusion was used to assess antigen-antibody reactions between extracted soluble protein and the serum from immunized rats, Rattus norvegicus prior to analysis of human sera. These results were comparable to results of immunoelectrphoresis. Jigger protein isolates were analyzed in Sodium Dodecyl Sulfate Polyacrylamide Gel Electrophoresis technique (SDS—PAGE), against Pharmacia standard protein markers. Further analysis of jigger antigens against pooled human sera from infested victims in Western blot revealed three immunodominant antigens. Using simple regression analysis molecular weights of the three immunodominant antigens were estimated as 51.795, 23.395 and 15.38 kDa respectively. These results are important since they would help understand immunological behavior of the parasites. This would help to create basis for designing and improving approaches against jiggers such as development of immune prophylaxis to complement social science approaches that is mainly concerned with maintenance of high standards of hygiene.

Factor VIII alloantibody inhibitors: cost analysis of immune tolerance induction vs. prophylaxis and on-demand with bypass treatment.

Development of inhibitors (alloantibodies to exogenous factor VIII) is the most significant treatment complication in patients with haemophilia A. The only proven way to eradicate inhibitors is through immune tolerance induction (ITI), while bypassing agents are typically employed to treat or prevent bleeds in patients with high titre inhibitors. Costs of these approaches have not been well studied. The aim of this study was to compare lifetime costs of treating patients with severe haemophilia A with inhibitors using on-demand or prophylaxis treatment with bypassing agents and ITI. A decision-analytic model was developed to compare the treatment costs and outcomes. Quantitation of the reduction in bleeding events for patients on prophylaxis and after eradication of inhibitors when on ITI and relapse of inhibitors was derived from published studies. Costs were obtained from standard US costing sources and are reported in 2014 US dollars. Costs and outcomes were discounted 3% per annum. Lifetime costs of treating patients with inhibitors are lower for ITI vs. on-demand or prophylaxis. Patients are also projected to live longer, have greater quality-adjusted life-years, and have fewer bleeding events than patients treated on-demand. Treating patients via ITI to eradicate inhibitors may result in lower lifetime costs and greater life-years and quality-adjusted life-years than treating with bypassing agents.

Hepatitis B Immune Globulin Prophylaxis of Viral Reactivation during Stem Cell Transplant

Hepatitis B Immune Globulin Prophylaxis of Viral Reactivation during Stem Cell Transplant

Assessment of humoral immune response of a Cytomegalovirus DNA-vaccine candidate in BALB/c mice

Introduction: Glycoprotein B (gB) is the major antigen for induction of humoral responses against human cytomegalovirus (HCMV) making it an attractive candidate for immune prophylaxis. In the present study, the humoral immune response of BALB/c mice to a truncated HCMV gB protein fused with GFP was evaluated.:The truncated gB coding sequence was synthesized and cloned in pEGFPN1 eukaryotic expression vector and expr essed in HEK 293T cell line. After optimization, expression of the recombinant truncated HCMV gB was verified using HRP - conjugated polyclonal antibody specific for HCMV gB.The level of humoral immune responses was assessed in mice using DNA/DNA, peptide/peptide, and DNA/ peptide (prime -boost) immunization strategies. Results:Cloning of the truncated gB coding sequence in the pEGFPN1 was verified by restriction enzyme analysis and sequencing. After optimizing the transfection procedure the number of the GFP positive cells reached 32%. Western blot analysis confirmed theinvitroexpression of the truncated HCMV gB protein with an appa rent molecular weight of approximately 70 kDa.In vivoprime-boost immunization using HCMV gB DNA/peptide regimen showed significantly higher humoral immune responses compared to the control groups. Conclusion:This study demonstrated that thepEGFPN1 eukaryotic expression vector could be usedto optimize and evaluate the expression of this truncated protein.The results also showed that the DNA/peptide vaccination could induce a significant antibody response in animal model.

Management Strategies for Posterior Reversible Encephalopathy Syndrome (PRES) in Patients Receiving Calcineurin-Inhibitor or Sirolimus Therapy for Hematologic Disorders and Allogeneic Transplantation

▪Background: Posterior reversible encephalopathy syndrome (PRES) is a potentially life-threatening complication of therapy with calcineurin inhibitors (CNI). Medications in this class include tacrolimus (Tac) and cyclosporine A (CSA). Sirolimus (Siro), an inhibitor of the mammalian target of rapamycin (mTOR) complex, may also be associated with PRES. These therapies are generally used in the management of patients with severe aplastic anemia (SAA), to prevent or treat graft-versus-host disease following allogeneic hematopoietic cell transplantation (alloHCT), or to prevent rejection of solid organ allografts. PRES is associated with hypertension and symptomatic features include headaches, seizures, and occasionally, intracranial hemorrhage or ischemic strokes. Classical findings on magnetic resonance imaging (MRI) studies include leukoencephalopathy with vasogenic edema in the occipital cerebrum. Diffusion restriction is observed on diffusion-weighted imaging. Management of CNI/Siro-associated PRES has not been well-studied.Methods: We performed a single-institution retrospective review of all patients identified to have possible PRES on MRI between October 2000 and February 2014. Patients were identified by searching a database of all neuroimaging studies performed at our institution during this time period for the terms: PRES, posterior reversible encephalopathy, or reversible posterior leukoencephalopathy. Radiography studies were reevaluated for this study to uniformly collect data regarding imaging features. Medical chart review was conducted to determine patient features at diagnosis, management decisions with focus on medication changes, and outcomes.Results: Our review identified 191 patients who underwent 236 MRI studies that demonstrated findings suggesting a possible diagnosis of PRES. On medical record review, pertinent clinical data were available for 167 patients, of whom 93 (56%) were deemed to have a clinical diagnosis consistent with PRES. Amongst this cohort, 27 patients (29%) were diagnosed with PRES while taking a CNI or Siro – 22 (81%) were receiving Tac, 4 (15%) were receiving CSA, and 1 patient (3.7%) was receiving Siro at diagnosis. The median age at PRES diagnosis was 52 (range 7 - 68), with no apparent association between age and the occurrence of CNI/Siro-associated PRES. Indications for CNI/Siro therapy included: alloHCT (19%), SAA (3.7%), systemic lupus erythematosus (7.4%), and solid organ transplantation (70%). Symptomatic features and physical signs at diagnosis of CNI/Siro-associated PRES included: hypertension (74%), seizure (52%), headache (44%), intracranial hemorrhage (22%), and cerebrovascular accident (15%). Presentation with these symptoms was not significantly different between CNI/Siro-associated PRES and other forms of PRES (p = 0.36, 0.48, 0.88, 0.97, and 0.44, respectively). The median time from initiation of CNI/Siro therapy to onset of PRES was 22 days (range 1 - 1924). Only 3 patients (11%) discontinued CNI/Siro therapy at PRES diagnosis and did not resume, whereas 12 (44%) continued the same medication, 10 (37%) were changed to alternative CNI (Tac-to-CSA or CSA-to-Tac) therapy, and 2 (7.4%) were changed from CNI to Siro. Two patients experienced recurrent PRES following these initial management decisions. All other patients continued therapy without recurrence.Conclusions: CNI/Siro therapy, mostly in the setting of allogeneic hematopoietic cell or solid organ transplantation, was associated with roughly one-third of PRES cases at our institution. Management of CNI/Siro-associated PRES has not been well studied, and the low incidence of this complication is prohibitive to the implementation of prospective studies. In this retrospective review, we evaluated the management strategies and outcomes of patients who developed PRES while receiving CNI/Siro therapy. The vast majority of patients (77%) tolerated continuation of the same CNI or changing to alternative CNI therapy. An additional 11% tolerated conversion from CNI to Siro. The recurrence rate with continuation of CNI/Siro therapy was low at 2/24 (8.3%) and no patients experienced fatal complications of PRES, suggesting this management strategy is safe. Additional analyses are underway to determine whether clinical or radiographic features may help predict the recurrence of PRES in patients who continue CNI/Siro therapy. DisclosuresOff Label Use: Off-label use of tacrolimus, cyclosporine, and sirolimus for immune prophylaxis in hematopoietic cell transplant patients is discussed..

Effect of size and temperature at vaccination on immunization and protection conferred by a live attenuated Francisella noatunensis immersion vaccine in red hybrid tilapia

Francisella noatunensis subsp. orientalis (Fno) is a pleomorphic, facultative intracellular, Gram-negative, emerging bacterial pathogen of marine and fresh water fish with worldwide distribution. In this study, the efficacy of an attenuated Fno intracellular growth locus C (iglC) mutant was evaluated for use as a live immersion vaccine, when administered to hybrid tilapia at two different stages of growth (5 g fry and 10 g fingerlings) and at two temperatures (25 °C and 30 °C). To determine vaccine efficacy, mortality, days to first death, and Fno genome equivalents (GE) in the spleens of survivors, as well as serum and mucus antibody levels, were evaluated after 30 d in fish challenged with a wild type virulent strain. Both size and temperature at vaccination played an important role in immunization and protection. Fry vaccinated at 25 °C were not protected when compared to non-vaccinated fry at 25 °C (p = 0.870). In contrast, 5 g fry vaccinated at 30 °C were significantly protected compared to non-vaccinated fry at 30 °C (p = 0.038). Although lower mortalities occurred, 10 g fingerlings vaccinated at 25 °C were not protected, compared to non-vaccinated fingerlings at 25 °C (p = 0.328), while, 10 g fingerlings vaccinated at 30 °C were significantly protected, compared to non-vaccinated fingerlings at 30 °C (p = 0.038). Additionally, overall mortality of 5 g fish was significantly higher than in 10 g fish. Mortality was also significantly higher in fish subjected to a 30 to 25 °C temperature change one week prior to challenge, than in fish maintained at the same temperature during vaccination and challenge. This information demonstrates that both temperature and size at vaccination are important factors when implementing immunization prophylaxis in cultured tilapia.

Discrete conformations of epitope II on the hepatitis C virus E2 protein for antibody-mediated neutralization and nonneutralization.

The X-ray crystal structure of epitope II on the E2 protein of hepatitis C virus, in complex with nonneutralizing antibody mAb#12, has been solved at 2.90-Å resolution. The spatial arrangement of the essential components of epitope II (ie, the C-terminal α-helix and the N-terminal loop) was found to deviate significantly from that observed in those corresponding complexes with neutralizing antibodies. The distinct conformations are mediated largely by the flexibility of a highly conserved glycine residue that connects these components. Thus, it is the particular tertiary structure of epitope II, which is presented in a spatial and temporal manner, that determines the specificity of antibody recognition and, consequently, the outcome of neutralization or nonneutralization.

Noninvasive fetal RhD genotyping

Immunization against RhD is the major cause of hemolytic disease of the fetus and newborn (HDFN), which causes fetal or neonatal death. The introduction of postnatal immune prophylaxis in the 1960s drastically reduced immunization incidents in pregnant, D-negative women. In several countries, antenatal prophylaxis is combined with postnatal prophylaxis to further minimize the immunization risk. Due to lack of knowledge of the fetal RhD type, antenatal prophylaxis is given to all D-negative women. In the European population, approximately 40% of pregnant women carry a D-negative fetus and are thus at no risk of immunization. Noninvasive fetal RhD genotyping enables antenatal prophylaxis to be targeted to only those women carrying a D-positive fetus to avoid unnecessary treatment. Based on an analysis of cell-free fetal DNA from the plasma of pregnant women, this approach has recently undergone technical improvements and rapid clinical implementation. As a screening assay, the sensitivity is >99.3% from a gestational age of approximately 10-11 weeks. In addition, fetal RhD genotyping is widely used to assess the risk of HDFN in anti-D immunized women.

An iron-acquisition-deficient mutant of Corynebacterium pseudotuberculosis efficiently protects mice against challenge

Caseous lymphadenitis (CLA) is a chronic disease that affects sheep and goats worldwide, and its etiological agent is Corynebacterium pseudotuberculosis. Despite the economic losses caused by CLA, there is little information about the molecular mechanisms of bacterial pathogenesis, and current immune prophylaxis against infection has been unable to reduce the incidence of CLA in goats. Recently, 21 different mutant strains of C. pseudotuberculosis were identified by random mutagenesis. In this study, these previously generated mutants were used in mice vaccination trials to develop new immunogens against CLA. Based on this analysis, CZ171053, an iron-acquisition-deficient mutant strain, was selected. After challenge with a virulent strain, 80% of the animals that were immunized with the CZ171053 strain survived. Furthermore, this vaccination elicited both humoral and cellular responses. Intracellular survival of the bacterium was determined using murine J774 cells; in this assay, the CZ171053 had reduced intracellular viability. Because iron acquisition in intracellular bacteria is considered one of their most important virulence factors during infection, these results demonstrate the immunogenic potential of this mutant against CLA.

Risk factors for intrauterine infection with hepatitis B virus

ObjectiveTo investigate risk factors for hepatitis B virus (HBV) intrauterine infection. MethodsPeripheral blood samples and clinical data were collected from 174 pregnant women who were positive for hepatitis B surface antigen (HBsAg). Their 176 neonates received an active–passive immunization schedule at 0, 1, and 6months. Blood samples from the infants, collected before immune prophylaxis administration, were tested for HBV markers and HBV DNA. ResultsThe intrauterine infection rate at 6months after birth was 5.1%. Maternal HBV DNA positivity (OR 11.362; 95% CI, 1.389–92.931), hepatitis B e antigen (HBeAg) positivity (OR 7.278; 95% CI, 1.734–30.538), and thalassemia minor (OR 15.619; 95% CI, 2.239–108.964) were associated with intrauterine infection. The intrauterine infection rate for mothers with 105 copies/mL of serum HBV DNA or more was 18.2%, compared with 0.8% for mothers with less than 105 copies/mL. ConclusionA positive HBsAg test at 24hours and/or 1month of age followed by a positive test at 6months is an objective and comprehensive criterion for the diagnosis of HBV intrauterine infection. Maternal HBV DNA positivity (especially 105 copies/mL of HBV DNA or more), HBeAg positivity, and thalassemia minor are risk factors for HBV intrauterine infection.

Telbivudine during the second and third trimester of pregnancy interrupts HBV intrauterine transmission: a systematic review and meta-analysis.

BECKGROUND: Evaluate the efficacy and safety of telbivudine during the 2nd and 3rd trimester of pregnancy in intrauterine transmission of hepatitis B virus (HBV). Based on the principle of Cochrane systematic reviews, a database was constructed from Medline, EMBASE, Cochrane Library, the US National Science Digital Library (NSDL), the China Biological Medicine Database (CBM-disc), and contact with Chinese experts in the field from November 2006 to February 2013. The Critical Appraisal Skills Programme (CASP) of Oxford, Cochrane Collaboration's tool, and Review Manager Version 5.0 (Rev-Man 5.0) for assessing the quality of clinical trials, risk of bias, and statistical analysis was used. We analyzed the effects and safety of telbivudine treatment on intrauterine mother-to-child transmission (MTCT) of HBV from HBsAg and HBV-DNA positive mothers. All newborns received an immune prophylaxis schedule consisting of simultaneous hepatitis B virus vaccine and hepatitis B immunoglobulin (HBIG) postpartum. Of 32 studies, 7 studies fulfilled the inclusion criteria in the study. Either the Mantel-Haenszel or Inverse Variance fixed-effects model or Mantel-Haenszel or Inverse Variance random-effects model was applied for all analyses indicated by odds ratio (OR) and 95% confidence interval (CI). The meta-analysis based on new onset of HBsAg seropositivity of infants at 6-12 months postpartum revealed that the control group had an intrauterine transmission rate of 8.25-42.31%. This rate was reduced to 0-14.29% in the telbivudine treatment group (OR 0.09, 95% CI 0.04-0.22, including seven trials, p < 0.001). The rates of intrauterine transmission based on new onset of HBV DNA seropositivity of infants at 6-12 months postpartum were 8.25-19.23% in the control group and 0 - 3.57% in the treatment group (OR 0.07, 95% CI 0.02-0.22, p < 0.001, including only five trials, since two trials had no data on HBV DNA in infants). With the exception of CK elevations, adverse effect frequencies were similar in both groups. Telbivudine is an effective and safe drug for preventing intrauterine transmission of HBV.