Safety and immunogenicity of a combined diphtheria-tetanus-acellular pertussis-inactivated polio vaccine-Haemophilus influenzae type b vaccine administered at 2-4-6-13 or 3-5-12 months of age

METHODS

In an open randomized study we compared the safety and immunogenicity of two schedules for priming and booster vaccinations of infants. A pentavalent combination vaccine, including a lyophilized Haemophilus influenzae type b-tetanus toxoid conjugate vaccine reconstituted with a liquid diphtheria, tetanus, acellular pertussis (pertussis toxoid and filamentous hemagglutinin) and inactivated polio vaccine (DTaP-IPV/Act-HIB; Pasteur Mérieux Connaught, Lyon, France) was administered to 236 Swedish infants either at 2, 4 and 6 months or at 3 and 5 months, and a booster dose was administered 7 months after the last primary dose. Adverse events were monitored by diaries for 3 days after each vaccination and by questions at the ensuing visits. Antibodies against the different vaccine components were analyzed after the primary series of vaccinations, before and after the booster injections.

RESULTS

There were no serious adverse reactions, and the rates of febrile events and local reactions were low in both groups. The three dose primary schedule induced higher geometricmean concentrations for all antigens than did the two dose schedule, but there were no differences between the groups in proportions with protective antibody titers against diphtheria, tetanus, Hib and polio or in proportions with certain defined levels of pertussis antibodies. Prebooster results showed a similar pattern, with the exception that the group primed with three injections showed higher proportions of infants with detectable antibodies against polio-virus types 1 and 3. After booster vaccinations there were no differences between the two schedules in geometric mean or in proportions with antibodies above defined antibody concentrations, indicating effective priming from both primary series of vaccinations. Conclusion. The combined vaccine DTaP-IPV/ Act-HIB vaccine was equally safe and immunogenic when administered according to both time schedules studied.

Type I Helicobacter pylori shows Lewis(b)-independent adherence to gastric cells requiring de novo protein synthesis in both host and bacteria

Type I Helicobacter pylori strains frequently recognize the Lewisb (Leb) blood group antigen. This binding property and expression of the Leb oligosaccharide were required for adherence to fixed normal or pathologic gastric tissue. In contrast, both type I and type II strains adhered to cultured cells in the absence of the Leb epitope. For the gastric cell line AGS, adherence was significantly higher when viable type I strains were allowed to interact with viable AGS cells compared with fixed cells. The observation that chloramphenicol and cycloheximide, inhibitors of bacterial and eukaryotic protein synthesis, respectively, significantly reduced adherence of type I but not type II isolates suggests that in type I strains, adherence depends on the up-regulation of one or more host cell receptors triggered by the bacterium.

Capture EIA for determination of IgE to diphtheria and tetanus toxins in comparison to RIA

A capture IgE assay in EIA with diphtheria toxin and tetanus toxoid as model systems was developed and evaluated in relation to RIA in a DT booster study. The EIA and the RIA gave very similar results, although the EIA determined IgE over a wider range of concentrations, without interference by other subclasses. The comparison to the capture EIA indicated that the RIA gave more reliable results when a toxin as antigen. Weak correlations between local side effects and IgE responses and differences between vaccine groups were noted by RIA but not by EIA, which correlated better with the clinical findings.

The European Union Concerted Action World Wide Web site for Lyme borreliosis

This web site (URL http://www.dis.strath.ac.uk/vie/LymeEU/) provides information on Lyme borreliosis for physicians, scientists, health care workers, veterinarians and students. It consists of a review of the spirochaetes, vectors, reservoir hosts, diagnosis, treatment, epidemiology and prevention of the disease, as well as an account of the activities of EUCALB.

European Lyme borreliosis clinical spectrum

At a series of meetings, involving 27 clinicians from 11 countries, case definitions for the diagnosis of Lyme borreliosis in Europe were agreed and are presented here, with appropriate serological criteria, as a diagnostic guide. In a separate study questionnaires directed to clinicians were used to collect information on clinical aspects and risk factors of Lyme borreliosis. Data on the number of Lyme borreliosis patients seen by physicians indicated a low prevalence of the disease in western Europe and a relatively high prevalence in eastern Europe. The most commonly encountered symptom was erythema migrans, followed by neurological manifestations. Cardiac problems were rare. Tick bite was strongly associated with Lyme borreliosis, but the only other significantly associated risk factor was the pastime of gardening.

Epidemiology of European Lyme borreliosis

Lyme borreliosis occurs throughout Europe and is particularly prevalent in the east. In a small proportion of untreated cases serious sequelae may occur, but Lyme borreliosis alone does not cause death. Clinical and serological diagnosis can still be problematic and the various genomospecies may cause different disease manifestations as well as differing immunological responses. However, considerable progress has been made in standardising case definitions and serological testing and interpretation. Few countries have official reporting systems for Lyme borreliosis and most figures on incidence are extrapolated from serodiagnosis data and seroprevalence studies. Geographical variations in incidence seem to correlate with the prevalence of infected ticks, which are mainly associated with varied deciduous forest. The complex ecology of Lyme borreliosis makes it difficult to implement preventive measures, so improving public knowledge of risk factors and methods for personal protection remain the best option at present.

Lyme borreliosis awareness

A Lyme borreliosis information leaflet has been produced to promote awareness amongst the general public. It was designed to provide a framework for similar material throughout Europe and complements a questionnaire produced to measure awareness of Lyme borreliosis. This questionnaire can be used to determine the impact of educational campaigns using material such as the leaflet. Feasibility studies showed that the questionnaire successfully highlighted predictable differences between sample groups and also that the leaflet performed well in increasing knowledge in low-awareness groups.

Immunoglobulin E and G responses to pertussis toxin in children immunised with adsorbed and non-adsorbed whole cell pertussis vaccines

The IgE and IgG responses to pertussis toxin were measured in blood samples from 70 children (age 1.5-2.9 years) after primary immunisation with either a non-aluminium adsorbed, whole cell vaccine (n = 34) or an aluminium adsorbed whole cell vaccine (n = 36). Two years later, they received a booster immunisation with either the non-adsorbed (n = 24) or the aluminium adsorbed vaccine (n = 14). Neutralising antibodies to pertussis toxin were higher (P < 0.05) after the three priming doses of the adsorbed vaccine than of the non-adsorbed vaccine, although both groups showed > 90% seropositives after the third dose. IgE antibodies to PT (PT-IgE) were detected in samples from 11/52 children after completed primary immunisation and the levels were low (median < or = 0.1 PRU ml-1) in both groups. No significant differences between the groups were found. PT-IgE levels did not increase after the booster injection. Thus, the aluminium content of the whole cell vaccines influenced the IgG response but not the IgE responses to pertussis toxin. The high rates of PT-IgE responses noted after a booster dose of acellular or whole cell pertussis vaccine to children primed with acellular vaccine in previous studies can therefore be mainly ascribed to the nature of the priming vaccine rather than the aluminium adjuvant.

Immunoglobulin E and G antibodies two years after a booster dose of an aluminium-adsorbed or a fluid DT vaccine in relation to atopy

Immunoglobulin E and G levels to diphtheria and tetanus toxoids were investigated two years after a DT booster with either an adsorbed or a nonadsorbed, fluid vaccine, given at 10 years of age. Although IgE levels had declined, detectable IgE to diphtheria and tetanus toxoids were still found in 82% and 67% of samples, respectively, to be compared to prebooster levels of 3-14% and postbooster levels of 92-94%. The IgG levels had also declined but remained at equal and high levels in both the adsorbed and the fluid vaccine groups. The prevalence of allergic symptoms was similar in the two vaccination groups. Thus, the study showed an unexpected, long duration of the IgE responses elicited by a booster dose of DT vaccine. The booster dose also induced a durable, high IgG antibody response to both the adsorbed and the fluid vaccine.

A population-based seroepidemiologic study of human granulocytic ehrlichiosis and Lyme borreliosis on the west coast of Sweden

Ehrlichioses are emerging infections in the United States. Human granulocytic ehrlichiosis (HGE) and Lyme borreliosis (LB) are acquired after Ixodes ricinus-complex tick bites. An ongoing seroepidemiologic study of the 185 of the 356 permanent residents of the Koster Islands in Sweden was expanded to include ehrlichioses. Ehrlichial antibodies were measured by IFA using Ehrlichia equi and Ehrlichia chaffeensis. Borrelia burgdorferi IgG ELISA-seropositive subjects were confirmed by Western blot. E. equi and E. chaffeensis antibodies (titer > or = 80) were found in 21 (11.4%) and 2 (1.1%) of 185 samples, respectively. Antibodies to B. burgdorferi were found in 25 (13.5%) of 185. Six persons were seropositive for both HGE and LB. Among data from questionnaires, clinical symptoms, antibiotic treatments, or tick bites were not more frequent in E. equi- or B. burgdorferi-seropositive than -seronegative persons. The seroprevalence of HGE was similar to that of Lyme borreliosis. Prospective studies of European HGE are needed.

Seroepidemiology of Helicobacter pylori infection in a cohort of children monitored from 6 months to 11 years of age

A cohort of Swedish children was monitored from 6 months to 11 years of age. Immunoglobulin G (IgG) and IgA antibodies to Helicobacter pylori were measured in 1,857 serum samples, drawn at the ages of 6, 8, 10, 18 months and 2, 4, and 11 years. Of the 294 children, 40 (13.6%) were found to have been infected at some time. However, at 11 years of age, only 6 of 201 (3%) children were seropositive. The highest seroprevalence of positive results, 10%, was found at 2 years of age, and the highest incidence of 13.3% could be calculated for the period between 18 months and 2 years of age. There were no confirmed additional cases for children between 4 and 11 years of age. Infection with H. pylori thus occurs at an early age in a developed country (as well as in developing countries), and spontaneous clearance seems to be common.

Bordetella pertussis serotype of clinical isolates in Sweden during 1970-1995 and influence of vaccine efficacy studies

During the years 1970 to 1995, the serotypes of collected clinical isolates from the different regions of Sweden were examined. Vaccination using whole-cell pertussis vaccine decreased during the year preceding cessation of general vaccination of children in 1979. Although the total number of clinical isolates examined was limited up to 1978 compared to later years, serotype 1, 2, 3 clinical isolates generally predominated. During periodical pertussis outbreaks, serotype 1, 3 strains were isolated, the proportion of which was about equal to that of serotype 1, 2, 3 isolates. Following cessation of general vaccination in 1979, the proportion of both serotypes 1, 2, 3 and 1, 3 isolates gradually diminished, together contributing about 20 percent of the total number of isolates in 1995. Clinical isolates of serotype 1, 2 were identified in the year 1977, just before cessation of general vaccination in Sweden using whole-cell vaccine. Since then, this serotype has gradually increased to over 80 percent of total isolates in 1995, possibly indicating that the use of whole-cell pertussis vaccine was effective against this serotype or that the vaccine influenced serotype expression. Vaccine efficacy studies conducted in Sweden during 1986-87 using one and two-component vaccines (BIKEN) and in 1994-95 using two-component (SmithKline Beecham Pharmaceuticals) and five-component (Connaught Laboratories, Ltd.) vaccines are examined with the object of studying whether the vaccines showed any influence on the different serotypes of B. pertussis causing disease.

The diagnostic value of enzyme immunoassay and immunoblot in monitoring eradication of Helicobacter pylori

55 patients with severe ulcer disease and H. pylori infection, successfully treated with antimicrobials, were followed-up with repeated blood samples for up to 32 months. Sera were analysed by enzyme immunoassay (EIA) for IgG and IgA antibodies and by IgG immunoblot. The EIA for IgG antibodies showed a high sensitivity (100%), while IgA antibodies above the cut-off level were found in 55% of the patients. At a median of 77 days after onset of treatment, approximately 50% of the patients showed a significant decrease (> or = 50%) of IgG or had titres below the cut-off level. All patients but 1 had a significant decrease of IgG after 6-12 months. The decrease was slower for IgA. The H. pylori-specific 116 kDa and 19.5 kDa bands were found in all pre-treatment samples, but the decrease in median intensity of the bands was slower than for the IgG EIA. In the 32-months post-treatment samples, both bonds had an intensity still above 50% of the pre-treatment value. The study showed that the IgG EIA is a useful method for monitoring eradication of H. pylori. Immunoblot can detect previous H. pylori infection in EIA negative Individuals.

H2O2-driven reduction of the Fe3+-quin2 chelate and the subsequent formation of oxidizing species

The objective of this study was to compare effects of quin2 and EDTA in iron-driven Fenton-type reactions. Seven different assays for detection of strong oxidants were used: the DMSO, deoxyribose, benzoate hydroxylation, and plasmid DNA strand breakage assays, detection of 8-oxo-deoxyguanosine in deoxyguanosine mononucleosides and calf thymus DNA, and electron spin resonance with the spin-trap (4-pyridyl-1-oxide)-N-tert-butylnitrone (4-POBN) in the presence of ethanol or DMSO. With H2O2 and Fe3+, quin2 generally strongly increased the formation of reactive species in all assays, whereas with EDTA the results varied between the assays from barely detectable to highly significant increases compared to H2O2 and unchelated Fe3+. We found that the species produced in the reaction between Fe3+-quin2 and H2O2 behaved like the hydroxyl radical in all assays, whereas with Fe3+-EDTA no clear conclusion could be drawn about the nature of the oxidant. The effect of quin2 on the formation of oxidants on Fe2+ autoxidation, varied from generally inhibiting to slightly promoting, depending on the assay used. EDTA had a promoting effect on the amount of oxidant detected by all but one assay. None of the autoxidation systems produced DMSO or ethanol radical adducts with 4-POBN. In the presence of either chelator, H2O2, and Fe2+ DMSO and ethanol radical adducts of 4-POBN were produced. Using the Fe2+ indicator ferrozine, evidence for direct reduction of Fe3+-quin2 by H2O2 was found. Superoxide anion radical appeared to be less efficient than H2O2 as reductant of Fe3+-quin2 as addition of superoxide dismutase in the ferrozine experiments only decreased the amount of Fe2+ available for Fenton reaction by 10-20%. The main conclusions from our study are that the reduction of Fe3+-quin2 can be driven by H2O2 and that Fe2+ in the following oxidation step produces a species indistinguishable from free hydroxyl radical.

Endotoxemia in febrile patients with hematological malignancies. Relationship of type of bacteremia, clinical findings and serum cytokine pattern

The relation between gram-negative bacteremia, endotoxemia and cytokinemia in patients with hematological malignancies was studied. Serum endotoxin and cytokines (tumor necrosis factor-alpha, interleukin-1 receptor antagonist, interferon-gamma, interleukin-6 and interleukin-10) were determined in 24 patients with hematological malignancies. Patients were included at start of fever (n = 18) or during a temperature peak during continuous fever (n = 6; time = 0). Blood was drawn for cultures at time of inclusion. Additional samples were obtained and grouped in two time intervals (1-5 h and 6-12 h after inclusion). Endotoxin was detected in eight patients. Endotoxemia was more common among patients with bacteremia than among non-bacteremic patients (7/12 versus 1/12; p < 0.05). All studied cytokines showed a tendency to higher mean values at time 0 in patients with endotoxemia than in patients without endotoxemia. Significantly higher mean endotoxin values were seen at time 1-5 h in patients with gram-negative bacteremia (n = 6) than in patients without gram-negative bacteremia, and at time 0 in patients with chills (n = 6) compared to those without chills.

European Union Concerted Action on Risk Assessment in Lyme Borreliosis: clinical case definitions for Lyme borreliosis

The EU Concerted Action on Risk Assessment in Lyme Borreliosis (EUCALB) has consulted other clinicians and scientists in Europe to produce case definitions of the principal manifestations of European Lyme borreliosis. These case definitions will not only be helpful in supporting its own research interests, but are also intended to assist other clinicians in appropriate management and to support further studies aimed at determining the full clinical spectrum of the disease. The case definitions were achieved after a series of meetings organised by EUCALB with other expert clinicians and scientists from twelve European countries. The definitions and the diagnostic criteria presented thus represent the consensus reached at these meetings. The proposed case definitions consider skin, nervous system, cardiac and musculoskeletal presentations and the role of laboratory investigation in supporting diagnosis.

Diphtheria antitoxin titres six years after basic immunization of adults

Diphtheria antitoxin titres were analysed in 160 adults (median age 59 years, range 34-70), who completed basic vaccination with three doses of 7.5 Lf or 15 Lf of diphtheria toxoid (D) in a previous vaccination trial in 1987, in serum samples drawn 6 years later. The median titre had decreased from 3.2 IU ml-1 in the post vaccination samples to 0.2 IU ml-1 after 6 years in the 15 Lf group and 0.1 IU ml-1 in the 7.5 Lf group. An antitoxin titre of < 0.01 IU ml-1, a level usually considered to give no safe protection, was found in 21/73 (29%) individuals, who had received 7.5 Lf and in 12 of 87 (14%), who received 15 Lf diphtheria toxoid (P < 0.05). In the original study, the vaccinees were enrolled as unimmunized based on their own vaccination histories, but many participants had serological evidence of previous immunization. In the subgroup of 48 truly non-immune participants, i.e. without prevaccination titres and without booster response after the first injection, 46% (32% in the 15 Lf group and 58% in the 7.5 Lf group) had antitoxin levels of < 0.01 IU ml-1 6 years after basic vaccination. Therefore, individuals who have received basic vaccination with three doses of diphtheria toxoid need at least one booster injection 5-10 years later.

Enzyme-linked immunosorbent assay-based inhibition test for neutralizing antibodies to polioviruses as an alternative to the neutralization test in tissue culture

A poliovirus-binding inhibition test (PoBI test) was established for the quantitative determination of antibodies to polioviruses and was evaluated in comparison with the conventional neutralization test (NT). The first step of the PoBI test is an incubation of serial dilutions of test samples with inactivated poliovirus followed by the detection of free viral epitopes by a double antibody sandwich enzyme-linked immunosorbent assay with type-specific capture polyclonal antisera and type-specific neutralizing monoclonal indicator antibodies. A comparison of the PoBI test with the conventional NT for antibodies to all three types in 100 human serum samples showed excellent correlations (r > 0.95) over a wide range of antibody concentrations. The PoBI test, not necessitating live virus and tissue culture facilities, could be a simple alternative to the NT, and the principle of the assay is potentially applicable to other microbial systems.

Influence of high titers of maternal antibody on the serologic response of infants to diphtheria vaccination at three, five and twelve months of age

Diphtheria antitoxin was determined in serum from 44 pregnant women, of whom 26 had received one injection of diphtheria toxoid during pregnancy. Their infants were vaccinated with a combined diphtheria-tetanus vaccine at 3, 5 and 12 months of age. This vaccination schedule has been used in Sweden since 1986, replacing the old schedule of vaccination at 3, 4.5 and 6 months of age originally designed for diphtheria-tetanus-pertussis vaccine, which had not been used after cessation of general vaccination against pertussis in 1979. Serum samples from the infants were obtained at 3, 7 and 18 months of age. After 2 injections infants of mothers with high antitoxin titers, > or = 0.1 IU/ml, tended to have lower antitoxin titers than infants of mothers with low antitoxin concentrations (P = 0.067). All children had, however, antitoxin above the minimum protective level of 0.01 IU/ml. Median antitoxin titers were 1.6 IU/ml in both groups after the third booster injection. Four infants of mothers who had been vaccinated during pregnancy and who had titers of > or = 0.4 IU/ml did not reach the 0.1 IU/ml level after 2 injections: all 4 responded with high antitoxin titers after the third dose. Thus all infants were primed by 2 doses of vaccine, irrespective of maternal antibody concentration. The repressive effect of maternal antibody on titers noted after 2 doses was no longer observed after the third, booster dose.

Immunoglobulin E responses to diphtheria and tetanus toxoids after booster with aluminium-adsorbed and fluid DT-vaccines

Immunoglobulin E responses to diphtheria and tetanus toxoids were investigated in pre- and postbooster samples of 104 children given, at 10 years of age, a DT booster with either an adsorbed (n = 51) or a non-adsorbed, fluid vaccine (n = 53). Vaccination with adsorbed DT is part of a national immunisation programme and represents the first regular booster given to these children, primarily immunised with three doses of adsorbed DT at age 3-6 months. The vaccines, with a content of 30 Lf of diphtheria toxoid and 7.5 Lf of tetanus toxoid per millilitre, were given for booster in a dose of 0.25 ml as a deep subcutaneous injection. In the prebooster samples, 3 and 14% had measurable IgE to diphtheria and tetanus, respectively. These rates rose to 94 and 92% in the postbooster samples, respectively. The median (range) of IgE to tetanus among recipients of the adsorbed vaccine was 0.59 PRU ml-1 (< 0.1-17.5), as compared to 0.27 (< 0.1-8.22) in the recipients of the fluid vaccine (p = 0.027). The median IgE response to diphtheria toxoid in the whole group was 1.8 (< 0.1-17.5), with no significant difference between the two vaccines (p = 0.76). There was no correlation between the IgE and IgG responses (r < 0.07, p > 0.5) but the two IgE responses as well as the ratios of IgG/IgE showed strong correlations (r > 0.7, p < 0.001). The study thus revealed unexpectedly high rates of IgE responses to diphtheria and tetanus toxoids in a regular DT booster vaccination programme, which were associated to high rates of local side effects.(ABSTRACT TRUNCATED AT 250 WORDS)

Monitoring of endotoxin, interleukin-6 and C-reactive protein serum concentrations in neutropenic patients with fever

Serum endotoxin, interleukin-6 (IL-6) and C-reactive protein (CRP) were serially determined in 26 patients with hematological malignancies and chemotherapy-induced neutropenia who developed fever. Endotoxin in serum was detected in 69% of the patients, with the highest values being recorded in patients with gram-negative (Gr-) bacteremia. High levels of IL-6 were found after start of fever, and in 6/9 patients with Gr- bacteremia levels exceeded 200 ng/l in samples drawn within the first 72 hours. However, only in 2/17 patients with gram-positive bacteremias and blood culture-negative fever episodes did IL-6 exceed this concentration (p < 0.05). High CRP values (exceeding 100 mg/l) did not discriminate between Gr- and non-Gr- episodes (7/9 versus 10/17, respectively). In patients with fever at day 3-5 (n = 15), IL-6 values > 100 ng/l were associated with fever continuing for more than 7 days after start of the episode; contrarily, CRP values did not indicate the persistence of fever. Determination of IL-6 may be a better test than CRP in monitoring the acute response to infection in the neutropenic patient. A combination of high endotoxin and IL-6 values may indicate a Gr- bacteremia. This could have therapeutic implications before results of blood cultures are obtained.