Michal Mandelboim

The Effect of Infliximab and Timing of Vaccination on the Humoral Response to Influenza Vaccination in Patients with Rheumatoid Arthritis and Ankylosing Spondylitis

OBJECTIVESnTo assess the effect of the timing of vaccination in relation to administration of infliximab on the efficacy and safety of influenza vaccine in patients with rheumatoid arthritis (RA) and ankylosing spondylitis (AS).nnnMETHODSnThe study population comprised 38 patients treated with infliximab at a mean dosage of 3 mg/kg (20 RA patients; 18 AS patients; 23 RA controls (treated with disease modifying antirheumatic drugs other than anti-tumor necrosis factor-alpha; and 17 healthy controls). Split-virion inactivated vaccine containing 15 mug hemagglutinin/dose of each of A/New Caledionan/20/1999 (H1N1), A/Wisconsin/67/2005 (H3N2), and B/Malaysia/2506/2004 (M) was used. Patients treated with infliximab were divided into 2 groups: 22 were vaccinated on the day of administration of infliximab, while 16 received the vaccine 3 weeks after infliximab. Baseline and 4- to 6-week clinical assessment of disease activity included erythrocyte sedimentation rate and C-reactive protein for all patients, the 28-joint disease-activity score for RA patients, and Bath Ankylosing Spondylitis Disease Activity Index for AS patients. Hemagglutination inhibition (HI) antibodies were tested by a standard World Health Organization procedure. Response was defined as >or=4-fold rise in HI antibodies 4 to 6 weeks after vaccination, or seroconversion in patients with a nonprotective baseline level of antibodies (<1/40). Geometric mean titers (GMT) were calculated to assess the immunity of the whole group.nnnRESULTSnAt baseline, RA patients and controls had similar occurrence of protective levels of HI antibodies and GMT, while AS patients had lower levels reflecting lower rates of previous vaccination. Four weeks after vaccination, a significant and similar increase in GMT for each antigen was observed in all groups (P < 0.004) except in the RA-infliximab group, vaccinated 3 weeks after administration of infliximab, in whom the increase in GMT was not significant for H1N1 (P = 0.12) and H3 (P = 0.06). AS patients demonstrated an increase in GMT, independently of the time of vaccination. The percentage of responders was similar in all groups. The response was not affected by variables such as age, gender, methotrexate, or prednisone use. Parameters of disease activity remained unchanged. No adverse effects other than injection site pain were recorded.nnnCONCLUSIONSnInfluenza virus vaccine generated a good humoral response in RA and AS patients treated with infliximab.

Identification of the Brucella melitensis Vaccine Strain Rev.1 in Animals and Humans in Israel by PCR Analysis of the PstI Site Polymorphism of Its omp2 Gene

ABSTRACT Adverse effects of strain persistence and secretion in milk have been encountered with the Brucella melitensis vaccine strain Rev.1. Field isolates obtained from vaccinated animals and from a human resembled the vaccine strain Rev.1 by conventional bacteriological tests. The lack of a specific molecular marker that could specifically characterize the commercial vaccine strain prevented confirmation of the homology of the Rev.1-like field isolates to the vaccine strain. The composition of the omp2 locus from two gene copies with differences in their PstI restriction endonuclease sites was used to establish an epidemiologic fingerprint for the omp2 gene in the Rev.1 vaccine strain. Primers designed to amplify DNA sequences that overlap the PstI site revealed a single 282-bp DNA band common to all Brucella spp. Agarose gel electrophoresis of the PstI digests of the PCR products from strains 16M and the vaccine strain Rev.1 revealed a distinctive profile that included three bands: one band for the intact 282-bp fragment amplified from omp2a and two bands resulting from the digestion of the amplified omp2b gene fragment, 238- and 44-bp DNA fragments, respectively. Amplified fragments of 37 Rev.1-like isolates, including 2 human isolates, also exhibited this pattern. In contrast, DNA digests of all other Israeli field isolates, including atypical B. melitensis biotype 1 and representatives of the biotype 2 and 3 isolates, produced two bands of 238 and 44 bp, respectively, corresponding with the digestion of both omp2a and omp2b genes. This method facilitates identification of the Rev.1 vaccine strain in both animals and humans in Israel.

The cellular immune response to influenza vaccination is preserved in rheumatoid arthritis patients treated with rituximab

OBJECTIVESnYearly vaccination against influenza is currently recommended to patients with rheumatoid Arthritis (RA). Antibody and cell-mediated responses are both involved in the defense against influenza. Humoral responses to influenza vaccine are impaired in RA patients treated with rituximab (RTX). The objectives of this study were to comparatively assess cell mediated and humoral responses to influenza vaccination in RA patients with or without RTX-induced CD20 B-cell depletion.nnnMETHODSnTrivalent influenza subunit vaccine was administered to 46 RA patients and to 16 healthy controls. The RA group included 29 patients treated by RTX and 17 on conventional disease-modifying anti-rheumatic drugs (DMARDs), mostly methotrexate. Peripheral blood mononuclear cells and sera were obtained immediately before and 4-6 weeks after vaccination. Cell-mediated response to influenza antigens was evaluated by flow cytometry for activated CD4 T-cells. Humoral response was evaluated by haemagglutination inhibition assay.nnnRESULTSnCellular response: Cell-mediated responses were comparable in RTX-treated vs. DMARDs-treated patients. The recall postvaccination CD4+ cellular response was similar in RA patients and healthy controls. A positive correlation was found between CD19+ cell count on the day of vaccination and cellular response in RTX-treated RA patients. Humoral response: The antibody response rate was significantly impaired in the RTX group: being 26.4%, 68.4% and 47.1% in RTX-treated, DMARDs-treated and controls, respectively.nnnCONCLUSIONnCellular immunity to influenza vaccination in RTX-treated patients was similar to DMARDs-treated patients and healthy controls, while humoral immunity was severely impaired. The preservation of cellular immunity may explain the relatively low rate of infection among B-cell depleted patients.

Efficacy and safety of vaccination against pandemic 2009 influenza A (H1N1) virus among patients with rheumatic diseases.

To assess the efficacy and safety of vaccination against pandemic H1N1 virus in patients with rheumatoid arthritis (RA), systemic lupus erythematosus (SLE), psoriatic arthritis (PsA), and ankylosing spondylitis (AS) compared with healthy controls.

Onset of a pandemic: characterizing the initial phase of the swine flu (H1N1) epidemic in Israel

BackgroundThe swine influenza H1N1 first identified in Mexico, spread rapidly across the globe and is considered the fastest moving pandemic in history. The early phase of an outbreak, in which data is relatively scarce, presents scientific challenges on key issues such as: scale, severity and immunity which are fundamental for establishing sound and rapid policy schemes. Our analysis of an Israeli dataset aims at understanding the spatio-temporal dynamics of H1N1 in its initial phase.MethodsWe constructed and analyzed a unique dataset from Israel on all confirmed cases (between April 26 to July 7, 2009), representing most swine flu cases in this period. We estimated and characterized fundamental epidemiological features of the pandemic in Israel (e.g. effective reproductive number, age-class distribution, at-risk social groups, infections between sexes, and spatial dynamics). Contact data collected during this stage was used to estimate the generation time distribution of the pandemic.ResultsWe found a low effective reproductive number (Re= 1.06), an age-class distribution of infected individuals (skewed towards ages 18-25), at-risk social groups (soldiers and ultra Orthodox Jews), and significant differences in infections between sexes (skewed towards males). In terms of spatial dynamics, the pandemic spread from the central coastal plain of Israel to other regions, with higher infection rates in more densely populated sub-districts with higher income households.ConclusionsAnalysis of high quality data holds much promise in reducing uncertainty regarding fundamental aspects of the initial phase of an outbreak (e.g. the effective reproductive number Re, age-class distribution, at-risk social groups). The formulation for determining the effective reproductive number Reused here has many advantages for studying the initial phase of the outbreak since it neither assumes exponential growth of infectives and is independent of the reporting rate. The finding of a low Re(close to unity threshold), combined with identification of social groups with high transmission rates would have enabled the containment of swine flu during the summer in Israel. Our unique use of contact data provided new insights into the differential dynamics of influenza in different ages and sexes, and should be promoted in future epidemiological studies. Thus our work highlights the importance of conducting a comprehensive study of the initial stage of a pandemic in real time.

Evaluation of Simplexa Flu A/B & RSV for Direct Detection of Influenza Viruses (A and B) and Respiratory Syncytial Virus in Patient Clinical Samples

ABSTRACT We evaluated the performance of the Simplexa Flu A/B & RSV kit on 170 prospective respiratory samples using a modified protocol, supplied by the manufacturer, that eliminates the RNA extraction step. Overall, compared against our laboratory-developed assay, the assays sensitivity, specificity, and positive and negative predictive values were 95.1%, 99.6%, 98.7%, and 98.6%, respectively.

Relationships between A(H1N1)pdm09 influenza infection and infections with other respiratory viruses

A(H1N1)pdm09, a new influenza pandemic virus emerged in 2009. The A(H1N1)pdm09 infection had several unique characteristics which included rapid transmissibility and high morbidity in obese individuals, pregnant women and individuals suffering from chronic diseases.

Polymerase-chain-reaction-based diagnosis of viral pulmonary infections in immunocompromised children.

Viral pneumonia is a serious complication in immunocompromised children. Its aetiology is difficult to identify owing to the limitations of conventional microbiological tests. The aim of this study was to determine whether polymerase chain reaction (PCR) assays for respiratory viruses increase the diagnostic yield of bronchoalveolar lavage (BAL) in immunocompromised children.

Epidemiological changes of respiratory syncytial virus (RSV) infections in Israel.

RSV is the leading cause of lower respiratory-tract infections in infants and therefore demands in-depth epidemiological characterization. We investigated here the distribution of RSV types in Israel between the years 2005–2012. Clinical samples were collected from 11,018 patients hospitalized due to respiratory illnesses and were evaluated for the presence of various respiratory viruses, including RSV A and RSV B. Until 2008, each year was characterized by the presence of one dominant type of RSV. However, from 2008, both RSV A and B types were detected at significant levels, particularly among infants aged 0–2 years. Furthermore, significant changes in the RSV A and RSV B subtypes circulating in Israel since 2008 were observed. Finally, we demonstrate that, irrespectively of the changes observed in RSV epidemiology, when the pandemic H1N1pdm09 influenza virus appeared in 2009, RSV infections were delayed and were detected when infection with H1N1pdm09 had declined.

Effective multi-strain inhibition of influenza virus by anionic gold nanoparticles

The fight against highly contagious influenza infection is often hampered by the appearance of drug resistant strains and the inadequacy of vaccines targeted only against specific variants. In this article, we report a novel route to inhibit influenza using anionic gold nanoparticles, which show effective inhibition properties against several influenza strains. The inhibition of influenza, achieved through gold nanoparticles with different anionic groups, suggested that blocking of viral attachment to cell surface could be the primary mechanism of inhibition, although viral fusion inhibition could not be excluded. At the same time, variation in the degree of inhibition with the anionic groups indicated that the antiviral activity of the nanoparticles is not merely governed by the charge density but the functional group itself has a role to play.