Immunoglobulin E response to pertussis toxin in whooping cough and after immunization with a whole-cell and an acellular pertussis vaccine

Whole-cell pertussis vaccine in early infancy for the prevention of allergy in children

BACKGROUND

Atopic diseases are the most common chronic conditions of childhood. The apparent rise in food anaphylaxis in young children over the past three decades is of particular concern, owing to the lack of proven prevention strategies other than the timely introduction of peanut and egg. Due to reported in vitro differences in the immune response of young infants primed with whole-cell pertussis (wP) versus acellular pertussis (aP) vaccine, we systematically appraised and synthesised evidence on the safety and the potential allergy preventive benefits of wP, to inform recommendation for future practice and research.

OBJECTIVES

To assess the efficacy and safety of wP vaccinations in comparison to aP vaccinations in early infancy for the prevention of atopic diseases in children.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials, Ovid MEDLINE, Embase, and grey literature. The date of the search was 7 September 2020.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) and non-randomised studies of interventions (NRSIs) that reported the occurrence of atopic diseases, and RCTs only to assess safety outcomes. To be included studies had to have at least six months follow-up, and involve children under 18 years old, who received a first dose of either wP (experimental intervention) or aP (comparator) before six months of age.

DATA COLLECTION AND ANALYSIS

Two review authors independently screened studies for eligibility, extracted the data, and assessed risk of bias using standard Cochrane methods. We assessed the certainty of the evidence using GRADE. Our primary outcomes were diagnosis of IgE-mediated food allergy and all-cause serious adverse events (SAEs). Secondary outcomes included: diagnosis of not vaccine-associated anaphylaxis or urticaria, diagnosis of asthma, diagnosis of allergic rhinitis, diagnosis of atopic dermatitis and diagnosis of encephalopathy. Due to paucity of RCTs reporting on the atopic outcomes of interest, we assessed a broader outcome domain (cumulative incidence of atopic disease) as specified in our protocol. We summarised effect estimates as risk ratios (RR) and 95% confidence intervals (CI). Where appropriate, we pooled safety data in meta-analyses using fixed-effect Mantel-Haenszel methods, without zero-cell corrections for dichotomous outcomes.

MAIN RESULTS

We identified four eligible studies reporting on atopic outcomes, representing 7333 children. Based on a single trial, there was uncertain evidence on whether wP vaccines affected the risk of overall atopic disease (RR 0.85, 95% CI 0.62 to 1.17) or asthma only (RR 1.04, 95% CI 0.59 to 1.82; 497 children) by 2.5 years old.Three NRSIs were judged to be at serious or critical risk of bias due to confounding, missing data, or both, and were ineligible for inclusion in a narrative synthesis.  We identified 21 eligible studies (137,281 children) that reported the safety outcomes of interest. We judged seven studies to be at high risk of bias and those remaining, at unclear risk.  The pooled RR was 0.94 for all-cause SAEs (95% CI 0.78 to 1.15; I² = 0%; 15 studies, 38,072 children). For every 1000 children primed with a first dose of wP, 11 had an SAE. The corresponding risk with aP was 12 children (95% CI 9 to 13). The 95% CI around the risk difference ranged from three fewer to two more events per 1000 children, and the certainty of the evidence was judged as moderate (downgraded one level for imprecision). No diagnoses of encephalopathy following vaccination were reported (95% CI around the risk difference - 5 to 12 per 100,000 children; seven primary series studies; 115,271 children). The certainty of the evidence was judged as low, since this is a serious condition, and we could not exclude a clinically meaningful difference.

AUTHORS' CONCLUSIONS

There is very low-certainty evidence that a first dose of wP given early in infancy, compared to a first dose of aP, affects the risk of atopic diseases in children. The incidence of all-cause SAEs in wP and aP vaccinees was low, and no cases of encephalopathy were reported. The certainty of the evidence was judged as moderate for all-cause SAEs, and low for encephalopathy. Future studies should use sensitive and specific endpoints of clinical relevance, and should be conducted in settings with high prevalence of IgE-mediated food allergy. Safety endpoints should prioritise common vaccine reactions, parental acceptability, SAEs and their potential relatedness to the dose administered.

A cross-sectional study of the relationship between reported human papillomavirus vaccine exposure and the incidence of reported asthma in the United States

Objectives:

Asthma is a chronic disorder that affects persons of all ages impacting the quality of their lives. This cross-sectional hypothesis-testing study evaluated the relationship between human papillomavirus vaccine and the risk of an incident asthma diagnosis in a defined temporal period post-vaccination.

Methods:

The 2015–2016 National Health and Nutrition Examination Survey data were examined for a group of 60,934,237 weighted persons between 9 and 26 years old in Statistical Analysis Software.

Results:

Reported incident asthma significantly clustered in the year of reported human papillomavirus vaccination. When the data were separated by gender, the effects observed remained significant for males but not females.

Conclusion:

The results suggest that human papillomavirus vaccination resulted in an excess of 261,475 asthma cases with an estimated direct excess lifetime cost of such persons being US$42 billion. However, it is unclear what part of the vaccine and/or vaccine medium may have increased an individual’s susceptibility to an asthma episode, whether the asthma diagnosis represented one asthma episode or if it is chronic, and how much therapeutic support was needed (if any) and for how long, which would impact cost. Despite the negative findings in this study, routine vaccination is an important public health tool, and the results observed need to be viewed in this context.

Bordetella pertussis

Pertussis is a highly infectious vaccine-preventable cough illness that continues to be a significant source of morbidity and mortality around the world. The majority of human illness is caused by Bordetella pertussis, and some is caused by Bordetella parapertussis. Bordetella is a Gram-negative, pleomorphic, aerobic coccobacillus. In the past several years, even countries with high immunization rates in early childhood have experienced rises in pertussis cases. Reasons for the resurgence of reported pertussis may include molecular changes in the organism and increased awareness and diagnostic capabilities, as well as lessened vaccine efficacy and waning immunity. The most morbidity and mortality with pertussis infection is seen in infants too young to benefit from immunization. Severe infection requiring hospitalization, including in an intensive care setting, is mostly seen in those under 3 months of age. As a result, research and public health actions have been aimed at better understanding and reducing the spread of Bordetella pertussis. Studies comparing the cost benefit of cocooning strategies versus immunization of pregnant women have been favorable towards immunizing pregnant women. This strategy is expected to prevent a larger number of pertussis cases, hospitalizations, and deaths in infants <1 year old while also being cost-effective. Studies have demonstrated that the source of infection in infants usually is a family member. Efforts to immunize children and adults, in particular pregnant women, need to remain strong.

Transiently increased IgE responses in infants and pre-schoolers receiving only acellular Diphtheria-Pertussis-Tetanus (DTaP) vaccines compared to those initially receiving at least one dose of cellular vaccine (DTwP) - Immunological curiosity or canary in the mine?

BACKGROUND

Several previous studies have highlighted the strong Th2-polarising and IgE-promoting activity of the DTaP vaccine, but there is no evidence that this has pathological consequences and accordingly there is no current interest amongst vaccine developers in reformulating DTaP to attenuate these properties. In light of an apparent resurgence in pertussis in many countries, and emerging evidence from other areas of paediatric immunology of IgE-mediated interference with host defence mechanisms, this issue requires more detailed clarification.

METHODS

We have re-evaluated the impact of DTaP-only versus mixed DTwP/DTaP vaccination on Th2-dependent "bystander" IgE responses in three cohorts of children under different priming conditions, encompassing both vaccine-targeted and unrelated antigens including food allergens.

RESULTS

We confirm the generalised IgE-trophic activity of the DTaP vaccine in pre-schoolers and demonstrate similar (albeit transient) effects in infants. We additionally demonstrate that use of an alternative mixed infant priming schedule encompassing an initial dose of DTwP significantly attenuates this property.

INTERPRETATION

Central to our interpretation of these findings are studies demonstrating: (i) mixed DTwP/DTaP priming improves resistance to pertussis disease and attenuates the IgE-stimulatory component of long term vaccine-specific memory; (ii) IgE-mediated mechanisms can interfere with innate antiviral immunity and accordingly exacerbate airway symptoms in infected children. These observations, taken together with the data presented here, suggest a plausible mechanistic link between baseline pertussis-specific IgE titres in DTaP vaccinees and susceptibility to pertussis disease, which merits testing. Retrospective IgE analyses on sera collected from children at the time of presentation with pertussis could resolve this issue.

Vaccine allergy

Overdiagnosis of vaccine allergy is considered a major public health problem. This article discusses the different types of allergic reactions after immunization based on the timing (immediate vs nonimmediate) and the extent of the reaction (local vs systemic). The vaccine components potentially responsible for an allergic reaction are discussed, as well as the management of patients with a history of reaction to a specific vaccine and those with a history of allergy to one of the vaccine components.

DPT vaccine-induced lipoatrophy: an observational study

INTRODUCTION

Diphtheria Pertussis Tetanus (DPT) vaccine is universally used in infants and children. It is generally safe and well tolerated. Local reactions such as erythema, induration, palpable nodules, and injection site abscess are well known. Injection site lipoatrophy has not been reported earlier.

PATIENTS AND METHODS

Retrospective review of all cases presenting with lipoatrophy developing at injection site following DPT administration between 2000-2005 in 3 hospitals in New Delhi, India was performed. In each case, the patients were extensively evaluated for other possible causes of lipoatrophy.

RESULTS

8 infants (2 boys & 6 girls), age range 4-12 months, had presented with injection site lipoatrophy following DPT vaccination. The duration between the last injection and lipoatrophy ranged from 4 to 8 weeks. All had been administered the vaccine in the buttock instead of the thigh, as generally recommended in infants. Majority (6/8) developed lipoatrophy after the second dose. No systemic causes were found.

CONCLUSION

DPT vaccine may, in rare instances, lead to injection site lipoatrophy. Inadvertent administration into the subcutaneous fat of the buttock may have been causative. Other possible mechanisms are discussed. Paramedics and general practitioners need to be educated to administer intramuscular vaccines in the thigh in infants and young children.

Do vaccines modify the prevalence of asthma and allergies?

Epidemiological studies suggest the hypothesis that the increase in asthma and allergies in the industrialized world can be explained by a decline in the number of infectious diseases occurring during childhood. In the context of this 'hygiene hypothesis', is immunization in early life a risk factor for promoting allergic diseases? The majority of studies, especially those conducted with more extensive populations, have not found an increased risk, and although 'not finding an increased risk' is not the same as 'the non-existence of any risk at all', it seems that the evidence is tipped in favor of the absence of risk. Conversely, although some surveys have described a protective effect of vaccination, the majority refuted this result. If there is any effect, it is probably a weak one.

Vaccines, antibiotics, and atopy

PURPOSE

Early exposure to vaccines and antibiotics may increase the risk of developing atopy by protecting against infectious agents and reducing duration and severity of infections (the hygiene hypothesis). It may also shift the developing immune system towards a more allergic response. We assess possible associations in young allergy clinic patients.

METHODS

We conducted a case-control study of 6- to 16-year-old new allergy clinic patients who were skin tested for inhalant allergens during 1987-2001 and enrolled in KPNW since birth (n = 1074). Atopic cases had positive tests for at least one inhalant allergen. Non-atopic controls had negative tests for all inhalant allergens. Using logistic regression analysis, we estimated atopy odds ratios for vaccine and antibiotic exposure variables and associations between vaccine and antibiotic exposures during the first 2 years of life and subsequent new allergy diagnoses.

RESULTS

Atopy was not significantly associated with numbers of vaccine and antigen doses, or number of different antigens during the first 2 years of life. Number of antibiotic prescriptions was negatively associated with atopy risk. Neither exposure was significantly associated with risk of new allergy diagnoses in atopic children.

CONCLUSIONS

Atopy development appears to be unrelated to early vaccine exposure. Frequency of antibiotic prescriptions during early life, a proxy for infection frequency, appears to protect against allergic sensitization. Neither vaccines nor antibiotics appear to induce subsequent allergic reactions in atopic children.

Is childhood immunisation associated with atopic disease from age 7 to 32 years?

BACKGROUND

There is ongoing conjecture over whether childhood immunisation leads to an increased risk of developing atopic diseases.

OBJECTIVE

To examine associations between childhood immunisation and the risk of atopic disease.

METHOD

Immunisation histories of 8443 Tasmanian children born in 1961 obtained from school medical records were linked to the Tasmanian Asthma Study. Associations between immunisation status and atopic diseases were examined while adjusting for possible confounders using multiple logistic regression.

RESULTS

Diphtheria immunisation was weakly associated with an increased risk of asthma by age 7 years (odds ratio (OR) 1.3, 95% confidence interval (CI) 1.1 to 1.7), but there was no evidence of any association for four other vaccinations studied. An increased risk of eczema by age 7 years was associated with immunisation against diphtheria (OR 1.5, 95% CI 1.1 to 2.1), tetanus (OR 1.5, 95% CI, 1.1 to 2.0), pertussis (OR 1.5, 95% CI 1.1 to 1.9) and polio (OR 1.4, 95% CI 1.0 to 1.9) but not small pox. Similar but slightly weaker patterns of association were observed between the risk of food allergies and immunisation against diphtheria (OR 1.5, 95% CI 1.0 to 2.1), pertussis (OR 1.4, 95% CI 1.1 to 1.9), polio (OR 1.4, 95% CI 1.00 to 2.1) and tetanus (OR 1.30 95% CI 0.99 to 1.70), but not with small pox. There was no evidence of associations between immunisation history and hay fever, or incidence of later-onset atopic outcomes.

CONCLUSIONS

The few effects seen in this study are small and age-dependent, and nearly all our findings support numerous previous studies of no effect of vaccines on asthma. Based on these findings, the fear of their child developing atopic disease should not deter parents from immunising their children, especially when weighed against the benefits.

Acellular pertussis vaccine protects against exacerbation of allergic asthma due to Bordetella pertussis in a murine model

The prevalence of asthma and allergic disease has increased in many countries, and there has been speculation that immunization promotes allergic sensitization. Bordetella pertussis infection exacerbates allergic asthmatic responses. We investigated whether acellular pertussis vaccine (Pa) enhanced or prevented B. pertussis-induced exacerbation of allergic asthma. Groups of mice were immunized with Pa, infected with B. pertussis, and/or sensitized to ovalbumin. Immunological, pathological, and physiological changes were measured to assess the impact of immunization on immune deviation and airway function. We demonstrate that immunization did not enhance ovalbumin-specific serum immunoglobulin E production. Histopathological examination revealed that immunization reduced the severity of airway pathology associated with sensitization in the context of infection and decreased bronchial hyperreactivity upon methacholine exposure of infected and sensitized mice. These data demonstrate unequivocally the benefit of Pa immunization to health and justify selection of Pa in mass vaccination protocols. In the absence of infection, the Pa used in this study enhanced the interleukin-10 (IL-10) and IL-13 responses and influenced airway hyperresponsiveness to sensitizing antigen; however, these data do not suggest that Pa contributes to childhood asthma overall. On the contrary, wild-type virulent B. pertussis is still circulating in most countries, and our data suggest that the major influence of Pa is to protect against the powerful exacerbation of asthma-like pathology induced by B. pertussis.

Acellular pertussis vaccines for adolescents

BACKGROUND

The epidemiology of pertussis is changing, with a clear increase in the number of cases diagnosed in adolescents and adults. This development has spurred studies and anticipated licensure of safer diphtheria, tetanus, acellular pertussis combined (Tdap) vaccines for this older population.

METHODS

Literature review.

RESULTS

Tdap vaccines are safe and immunogenic when administered to adolescents and adults. Correlates of immunity to pertussis after Tdap vaccination have not been established, but various combinations of antibody to pertussis antigens (pertussis toxin, filamentous hemagglutinin, pertactin, and fimbriae) provide protection. The importance of the number of antigens in Tdap vaccines for protection against mild pertussis disease is unclear. Pertussis vaccination establishes herd immunity after sufficient uptake within communities and countries. As experience with TdaP vaccines has accumulated, a 1-2% occurrence of large, local injection-site reactions with all TdaP vaccine products have been observed for booster doses in children 4-6 years of age. The frequency of large local reactions appears lower in adolescents and adults. The pathophysiologic mechanisms for the local reactions are not established, but a majority appears to be immunoglobulin E-mediated-reactive edema, and a minority appears to be immunoglobulin G-mediated Arthus-type reactions.

CONCLUSIONS

Tdap vaccines appear safe and immunogenic. The economic impact of pertussis provides a cost-benefit justification for widespread use of Tdap vaccine boosting in adolescents.

Acellular Pertussis Vaccine Safety and Efficacy in Children, Adolescents and Adults

This review offers a perspective on the acellular pertussis vaccine efficiency trials concluded in the 1990s and presents the main conclusions of a meta-analysis of 52 studies that assessed the safety and efficacy of the diphtheria-tetanus (DT)-whole cell pertussis (DTwP) and DT-acellular pertussis (DTaP) vaccines administered to children. A clear serological correlate of immunity to pertussis following DTaP vaccination was not identified despite an intensive analysis. It can be speculated that this may be because various combinations of antibody to agglutinogens (pertussis toxin, filamentous haemagglutinin, pertactin and fimbriae) provide protection, or because serum antibody levels and responses do not uniformly reflect mucosal IgA antibody levels.Long-term efficacy following DTaP vaccination is becoming characterised and cell-mediated immunity (T-cell memory) may have importance. DTaP vaccination appears to establish herd immunity after sufficient uptake within communities and countries. As experience with DTaP vaccine safety has accumulated, a 1-2% occurrence of large, local injection reactions with all products has been defined for booster doses. The pathophysiological mechanisms for the reactions are not established but a majority appear likely to be IgE-mediated reactive oedema and a minority to be IgG-mediated reactive Arthus-type reactions. DTwP and DTaP combinations with other vaccines have been studied and licensed; the most controversial combination products are the DTaP/Haemophilus influenzae type B polysaccharide conjugate vaccines. Pertussis epidemiology is changing with a clear increase in occurrence in adolescents and adults. This development has spurred studies and licensure of safer DTaP vaccines for this older population. The economic impact of pertussis and transmission from adults to vulnerable infants provides a cost-benefit justification for widespread use of DTaP vaccines in all age groups with routine boosting every 10 years.

Immunization and atopy: possible implications of ethnicity

The possible effects of immunization on subsequent development of asthma and atopy remains a matter of controversy. Although some studies have suggested that immunization might increase the risk for atopic disease, a number of studies have found no association or have even reported a protective effect for immunization against atopy. Recent studies have provided evidence that ethnicity might affect the susceptibility to the immunomodulatory effects of vaccination. In this review the association between immunization and atopy and the effect of ethnicity on this association are briefly outlined. The focus will be particularly on BCG vaccination.

Extensive swelling reactions occurring after booster doses of diphtheria-tetanus-acellular pertussis vaccines

Extensive local reactions are recognized to occur after administration of the fourth and fifth booster doses of diphtheria-tetanus-acellular pertussis (DTaP) vaccines. The incidence of these reactions is being delineated by prospective studies. Retrospective evaluations suggest that entire proximal limb swelling occurs in 2 to 6 percent of children given booster doses of DTaP vaccines. The reactions subside without sequelae, but they may be misdiagnosed as cellulitis and lead to unnecessary medical intervention. The pathogenesis of these reactions probably is multifactorial. Evidence suggests that both antigen content and prevaccination immunity have roles. Important, unanswered questions are the safety of revaccinating a child who previously has had an extensive local reaction and the safety of introducing further DTaP boosters into the adolescent and adult populations.

Childhood vaccinations and risk of asthma

BACKGROUND

A few previous studies have suggested that childhood vaccines, particularly whole cell pertussis vaccine, may increase the risk of asthma. We evaluated the suggested association between childhood vaccinations and risk of asthma.

METHODS

Cohort study involving 167,240 children who were enrolled in 4 large health maintenance organizations during 1991 to 1997, with follow-up from birth until at least 18 months to a maximum of 6 years of age. Vaccinations were ascertained through computerized immunization tracking systems, and onset of asthma was identified through computerized data on medical care encounters and medication dispensings.

RESULTS

In the study 18,407 children (11.0%) developed asthma, with a median age at onset of 11 months. The relative risks (95% confidence intervals) of asthma were: 0.92 (0.83 to 1.02) for diphtheria, tetanus and whole cell pertussis vaccine; 1.09 (0.9 to 1.23) for oral polio vaccine; 0.97 (0.91 to 1.04) for measles, mumps and rubella (MMR) vaccine; 1.18 (1.02 to 1.36) for Haemophilus influenzae type b (Hib); and 1.20 (1.13 to 1.27) for hepatitis B vaccine. The Hib result was not consistent across health maintenance organizations. In a subanalysis restricted to children who had at least 2 medical care encounters during their first year, the relative risks decreased to 1.07 (0.71 to 1.60) for Hib and 1.09 (0.88 to 1.34) for hepatitis B vaccine.

CONCLUSION

There is no association between diphtheria, tetanus and whole cell pertussis vaccine, oral polio vaccine or measles, mumps and rubella vaccine and the risk of asthma. The weak associations for Hib and hepatitis B vaccines seem to be at least partially accounted for by health care utilization or information bias.

Lack of consistent relationship between quantity of aluminum in diphtheria-tetanus-acellular pertussis vaccines and rates of extensive swelling reactions

The precise role that aluminum plays in local reactogenicity is not clear. We explored the relationship between rates of severe local reactions following the fourth and fifth booster doses of several diphtheria-tetanus-acellular pertussis vaccines (DTaP) and the quantity of aluminum contained in the different vaccines. Although there was a significant relationship between higher aluminum contents and swelling reactions >50 mm after dose 5, no relationship was seen with entire thigh swelling or with swelling >50 mm after dose 4. Because of the inconsistency of the data, a dose response between local reactogenicity and aluminum is questionable.

Wheezing lower respiratory disease and vaccination of full-term infants

PURPOSE

There have been speculations that increases in vaccinations have caused recent increases in wheezing lower respiratory disease during infancy. We assess possible associations between vaccines and incidence of wheezing in full-term infants.

METHODS

We conducted a matched case-control study of full-term infants born into the Kaiser Permanente Northwest health plan during 1991-1994 and continuously enrolled for at least 12 months (n = 1366 case-control pairs). Potential cases of wheeze were ascertained from medical care databases and verified by chart review. Vaccinations, demographic factors, and wheeze risk factors were abstracted from charts. Adjusted relative risks of first onset of wheeze during post-vaccination exposure windows were estimated by conditional logistic regression. We also conducted case-series analyses of wheeze onsets.

RESULTS

We found no evidence that risk of wheeze during infancy is associated with recency of vaccination with whole-cell pertussis (DTP), hepatitis b (HBV), Haemophilus influenzae type b (HIB), oral polio (OPV), or measles, mumps and rubella (MMR) vaccines. We also found no evidence that risk of first wheeze is associated with exposure to HBV or MMR.

CONCLUSIONS

Recent increases in wheezing during infancy do not appear to be related to increases in vaccinations of full-term infants.

Do early childhood immunizations influence the development of atopy and do they cause allergic reactions?

Concerns about allergic side-effects of vaccines and about a possible promotion of allergic diseases contribute to incomplete vaccination rates in childhood. This article reviews the current understanding of these issues. There is evidence that pertussis and diphtheria/tetanus antigens elicit immunoglobulin E (IgE) antibody formation as part of the immune response. In murine models, pertussis toxin is an effective adjuvant for IgE formation against simultaneously administered antigens. In children, however, sensitization to unrelated antigens or development of allergic diseases do not seem to be augmented. In contrast, bacille Calmette-Guérin (BCG) and measles vaccination have been proposed as suppressors of allergy because of their T helper 1 (Th1)-fostering properties. In the murine system, BCG inhibits allergic sensitization and airway hyper-reactivity. Some epidemiological studies in humans suggest an inhibitory effect of tuberculosis on allergy. BCG vaccination in children, however, has no or merely a marginal suppressive effect on atopy. Other vaccine components such as egg proteins, gelatin, and antibiotics are a potential hazard to children with severe clinical reactions to these allergens. These rare children should be vaccinated under special precautions. In conclusion, vaccination programs do not explain the increasing prevalence of allergic diseases, but individual children may uncommonly develop an allergic reaction to a vaccine. The risks of not vaccinating children, however, far outweigh the risk for allergy. Therefore, childhood vaccination remains an essential part of child health programs and should not be withheld, even from children predisposed for allergy.

Modulation of inhaled antigen-induced IgE tolerance by ongoing Th2 responses in the lung

The normal response to inhaled Ag is the absence of Ag-specific IgE and cytokine production to later Ag challenges. Although the mechanism of this aerosol-induced IgE tolerance is not completely understood, it may prevent sensitization to inhaled Ags, which could otherwise lead to allergy and asthma. We examined the consequences of ongoing Th1 and Th2 responses in the lungs of mice during OVA inhalation to mimic conditions that may subvert tolerance and lead to sensitization. We found that concurrent, secondary Th2 lung responses to keyhole limpet hemocyanin or primary responses to Nippostrongylus larvae or Asperigillus fumagatus extract prevented establishment of IgE tolerance to aerosolized OVA. Intranasal rIL-4 given before OVA aerosolization also prevented establishment of tolerance, whereas concurrent Th1 responses to influenza virus or Mycobacterium bovis bacillus Calmette-Guérin had no effect. However, once established, aerosol tolerance to OVA could not be completely broken by OVA rechallenge concurrent with a secondary Th2 response to keyhole limpet hemocyanin or A. fumagatus extract, or by intranasal rIL-4. These data suggest that the immune status of the lung of an individual may profoundly influence the initial response to inhaled Ag, and that aerosol-induced IgE tolerance may not be appropriately established in individuals undergoing concurrent, Th2-mediated responses to Ags or pathogens.

Booster immunization of children with an acellular pertussis vaccine enhances Th2 cytokine production and serum IgE responses against pertussis toxin but not against common allergens

Acellular pertussis vaccines (Pa) protect against severe pertussis in children. However, serum antibody responses decline quickly after immunization. Studies in animal models suggest that cell-mediated immunity also contributes to protection against Bordetella pertussis, and it has already been demonstrated that Pa induce T cells that secrete type-1 and type-2 cytokines in children. In this study we examined the persistence of the T cell response and the effect of booster immunization in 4-6-year-old children. Cell-mediated immunity to B. pertussis antigens was detected in a high proportion of children more than 42 months after their last immunization. Peripheral blood mononuclear cells (PBMC) from the majority of children secreted interferon-gamma (IFN-gamma) and a smaller proportion IL-5, in response to specific antigen stimulation in vitro. However, following booster immunization, significantly higher concentrations of IL-5, but not IFN-gamma, were produced by PBMC in response to B. pertussis antigens. Furthermore, plasma IL-4 and IL-5 concentrations were increased, whereas IFN-gamma concentrations were reduced following booster immunization. It has been suggested that childhood immunization with Th2-inducing vaccines may predispose some children to atopic disease. Although we found that pertussis toxin (PT)-specific IgE was significantly increased after booster immunization in both atopic and non-atopic children, the levels of IgE to common allergens and the prevalence of positive skin prick test were unaffected by the booster vaccination. Thus, despite the enhancement of type-2 responses to B. pertussis antigens, booster vaccination with Pa does not appear to be a risk factor for allergy.

Extensive swelling after booster doses of acellular pertussis-tetanus-diphtheria vaccines

BACKGROUND

Diphtheria and tetanus toxoid combined with acellular pertussis (DTaP) vaccines are less reactogenic than diphtheria and tetanus toxoid combined with whole cell pertussis (DTwP) vaccines. However, local reactions increase in rate and severity with each successive DTaP dose, and swelling of the entire injected limb has been reported after booster doses.

METHODS

We reviewed reports of swelling of the entire thigh or upper arm after the fourth and fifth dose, respectively, of DTaP vaccines administered in the National Institutes of Health multicenter comparative DTaP studies. Relationships were explored among reports of severe swelling, rates of other reactions, quantity of vaccine contents, and prevaccination and postvaccination antibody levels to pertussis toxin, tetanus toxin, and diphtheria toxin.

RESULTS

Entire thigh swelling was an unsolicited reaction reported in 20 (2%) of the 1015 children who received 4 consecutive doses of the same DTaP vaccine. The reaction was associated with 9 of the 12 DTaP vaccines evaluated. Although there were no reports of swelling of the entire upper arm in 121 children given a fifth dose of the same DTaP, 4 (2.7%) of 146 recipients of 5 doses of a mixed schedule of DTaP vaccines experienced such swelling. Rates of other reactions were higher in children with entire thigh swelling than in those without. Of the children with entire thigh swelling, 60% had local pain, and 60% had erythema. All swelling subsided spontaneously without sequelae. There was a significant linear association between the rates of entire thigh swelling after dose 4 and diphtheria toxoid content in the DTaP products. Lesser degrees of swelling (>50 mm but less than entire limb) correlated with pertussis toxoid content after dose 4 and aluminum content after dose 5. No relationship was established between levels of serum antibody to diphtheria, tetanus, or pertussis toxin and rates of swelling of the whole thigh.

CONCLUSIONS

Booster doses of DTaP vaccines can cause entire limb swelling, which is usually associated with redness and pain. Our data suggest that this extensive swelling reaction may be more common with vaccines containing high diphtheria toxoid content.

Comparison of a fifth dose of a five-component acellular or a whole cell pertussis vaccine in children four to six years of age

BACKGROUND AND OBJECTIVES

Acellular pertussis vaccines are now preferred for all five childhood immunization doses; however, there are few data on the safety and immunogenicity of five consecutive doses. This study compared a fifth dose of an acellular and a whole cell pertussis vaccine in 4- to 6-year-old children previously immunized with four doses of acellular or whole cell pertussis vaccine.

STUDY DESIGN

In a double blind, multicenter study, 366 healthy children were randomly allocated to receive a single injection of a 5-component acellular or a whole cell pertussis vaccine, each combined with diphtheria and tetanus toxoids and inactivated poliovirus vaccine.

RESULTS

Although injection site redness > or =50 mm and swelling > or =50 mm were common in children who had received five doses of acellular (50% and 48.1%, respectively) or whole cell (66.2% and 59.7%) pertussis vaccine, limb soreness and limitation of motion were less frequently reported after acellular (1.9% and 0%) than after whole cell (49.2% and 36.3%; P < 0.0001) pertussis vaccine. Pre-fifth dose antipertussis antibody titers were higher in children who previously had received four doses of acellular pertussis vaccine. Postimmunization antibody titers against pertussis toxin, filamentous hemagglutinin, pertactin and tetanus toxin were higher in recipients of five doses of acellular pertussis vaccine, whereas antibody titers to diphtheria toxin, pertussis fimbriae and poliovirus serotypes were higher in recipients of five doses of the whole cell pertussis vaccine (P < 0.05 for all comparisons).

CONCLUSIONS

A regimen consisting of five doses of a five-component acellular pertussis combination vaccine is safe and immunogenic in pre-school children. Local adverse reactions are common but are less painful and activity-limiting than a regimen of five doses of a whole cell pertussis vaccine.

Pertussis IgE and atopic disease

BACKGROUND

Pertussis toxin (PT) stimulates IgE production in animals, and pertussis vaccination and whooping cough may have similar effects in man.

METHODS

We analyzed IgE responses to PT (PT-IgE) in sera from children primarily immunized with three doses of either an acellular 2- or 5-component vaccine, or a whole-cell (Wc) pertussis vaccine, and in children after whooping cough. The study comprised 50 children with both atopic disease and positive skin prick test, 99 nonatopic controls, and 40 children with verified pertussis.

RESULTS

Immunoglobulin E antibodies against PT were demonstrated in 19% and 24% of sera from vaccinated children at 7 and 12 months, respectively, and in 9% at 2.5 years. At 7 months, PT-IgE was more common after vaccination with acellular (24%) than with the Wc vaccine (3%, P = 0.02). PT-IgE was also more common (P = 0.001) after vaccination in children classified as atopic (36%) than in the control group (10%). Thirty percent of the children with pertussis had PT-IgE, more often so in atopic than nonatopic children (P = 0.02).

CONCLUSIONS

Transient production of PT-IgE seems to be common after primary pertussis immunization with acellular vaccines, and after whooping cough, particularly in atopic subjects.

Differences in coughing and other responses to intrabronchial infection with Bordetella pertussis among strains of rats

Four strains of rats were each infected intrabronchially with approximately 10(8) CFU of Bordetella pertussis 18-323 encased in fine agarose beads. After 8 days, Sprague-Dawley rats developed the highest incidence of coughing paroxysms, as monitored with voice-activated tape recorders; Brown Norway, Lewis, and Hooded Lister rats coughed significantly less frequently. Marked leukocytosis, with counts up to four times the normal levels, and retardation of normal weight gain occurred in all four rat strains. Both coughing and leukocytosis were greater in animals that were infected at 4 weeks of age than in those infected at 6 weeks of age. Total serum immunoglobulin E (IgE) rose in all four rat strains 9- to 244-fold by day 8 after infection and returned to near preinfection levels at 6 weeks. Sprague-Dawley and Lewis rats, which had the lowest basal levels of total IgE in serum, showed the greatest degrees of elevation. All four rat strains had IgG to B. pertussis whole-cell sonicate and to filamentous hemagglutinin in 6-week-postinfection sera. However, the strains differed in production of IgG to pertussis toxin, with Sprague-Dawley rats having the highest titers and Hooded Lister and Lewis rats being nonresponders. These studies highlight the importance of rat strain as a variable in the coughing-rat model of pertussis and validate the choice of the Sprague-Dawley rats in previous studies.

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 cellular pertussis vaccine (Infanrix-DTPa; SB-3). A review of its immunogenicity, protective efficacy and tolerability in the prevention of Bordetella pertussis infection

SB-3 (Infanrix-DTPa) is one of a new generation of vaccines for immunisation against pertussis (whooping cough), diphtheria and tetanus. It is a 3-component (pertussis toxin, filamentous haemagglutinin and pertactin) chemically inactivated acellular pertussis pertussis-diphtheria-tetanus toxoid (DTaP) vaccine, and it differs from conventional whole-cell pertussis-diphtheria-tetanus toxoid (DTwP) vaccines in that it comprises inactivated purified Bordetella pertussis antigens rather than whole cells of the bacillus. SB-3, like a number of other DTaP vaccines, elicits a similar or more often, a significantly greater immune response than various DTwP vaccines in healthy infants and young children. initial data from comparative studies indicate that SB-3 also remains immunogenic when given in combination with hepatitis B vaccine or concurrently administered with Haemophilus influenzae type b (HbOC) conjugate vaccine. A combination of SB-3 and H. influenzae type b tetanus (PRP-T) conjugate vaccine results in lower anti-PRP antibody response than when both vaccines are administered concurrently. Data from two large, multicentre, German and Italian studies in infants indicate that the protective efficacy of SB-3 against pertussis was significantly better than one DTwP (DTwP-CON) but similar to another one (DTwP-BW) under investigation. Compared with another DTaP vaccine (BIO-3), SB-3 was just as protective. Overall, the data from these 2 studies indicate that primary vaccination with SB-3 provides effective protection against pertussis, even under the stringent conditions of a household contact with typical pertussis. As the other DTaP vaccines, SB-3 is better tolerated than DTwP vaccines, with a significantly lower incidence of common adverse events such as local reactions (swelling, pain and a erythema), irritability, fever, persistent crying and local tenderness. Clinical experience with SB-3 thus far indicates that, like other DTaP vaccines, it is associated with significantly fewer common (non-serious) adverse events than DTwP vaccines. Less clear is whether it has any advantage over DTwP vaccines with respect to protective efficacy or over other DTaP vaccines with respect to tolerability and protective efficacy. Nevertheless, the available data support the use of SB-3 for infant immunisation, as well as providing a suitable basis for the development of new combination vaccines.

Pertussis toxin enhanced IgG1 and IgE responses to primary tetanus immunization are mediated by interleukin-4 and persist during secondary responses to tetanus alone

Pertussis toxin (Ptx), the major toxin product of Bordetella pertussis, has potent immunologic effect including adjuvant effects on antibody responses and sensitization for anaphylaxis. In order to further define the effect of Ptx on the class and subclass of murine antibody response, we measured total and antigen specific IgG subclasses and IgE in Balb/c mice after primary and secondary immunization with tetanus toxoid (TT). Low doses of Ptx (100 ng) given intravenously at the time of primary immunization increased primary IgG1 and IgE anti-TT antibodies as well as total IgG1 and IgE concentrations compared to controls. The increase in IgG1 subclass and IgE response when Ptx was present during primary immunization was even more pronounced after secondary immunization with TT alone 3 weeks or 3 months later. Similar effects were noted after diphtheria toxoid immunization in the presence of Ptx. Administration of the anti IL-4 monoclonal antibody (11B11) suppressed the enhanced total and TT-specific IgE responses but not the enhanced IgG1 responses. The presence of low concentrations of Ptx during primary immunization primes for induction of IL-4 producing T-cell help which enhances IgGI and IgE responses to the primary exposure as well as to subsequent exposures of the antigen in the absence of Ptx. This phenomenon may have significance for the adjuvant activity of vaccines containing Ptx as well as for the immune response to natural pertussis.

Co-stimulation of T cells via CD28 inhibits human IgE production; reversal by pertussis toxin

In lymphocyte cultures, IgE production was achieved by stimulating T cells with anti-CD2 and IL-2. Here we show that anti-CD28, in the presence or absence of IL-2, reduces this IgE production approximately 10-fold. This inhibition of IgE production was almost completely reversed by Pertussis toxin (PT). PT had no effect on IgE production when the cells were stimulated in the absence of anti-CD28. No major effects of PT were found on IgM production. PT had no effect on purified B cells, stimulated with IL-4 and anti-CD40. In the presence of saturating amounts of rIL-4 similar results were obtained, albeit the absolute amounts of IgE produced were higher in all situations. Furthermore, PT-induced IgE production was still dependent on IL-4, as was evident from experiments in which anti-IL-4 was added to the culture. The IgE enhancing effect was dependent on the adenosine diphosphate (ADP)-ribosyltransferase activity of PT, because a mutant molecule lacking this activity was not able to restore anti-CD28-induced inhibition of IgE synthesis. Thus, we show that co-stimulation with anti-CD28 causes an inhibition of T cell-dependent IgE production by B cells, which inhibition can be specifically overcome by PT. An analysis of the molecular pathways underlying this phenomenon may contribute to our understanding of the regulation of IgE synthesis in (patho)physiological conditions.

Adjuvant properties of aluminum and calcium compounds

It is likely that aluminum compounds will continue to be used with human vaccines for many years as a result of their excellent track record of safety and adjuvanticity with a variety of antigens. For infections that can be prevented by induction of serum antibodies, aluminum adjuvants formulated under optimal conditions are the adjuvants of choice. It is important to select carefully the type of aluminum adjuvant and optimize the conditions of adsorption for every antigen since the degree of adsorption of antigens onto aluminum adjuvants markedly affects immunogenicity. The mechanism of adjuvanticity of aluminum compounds includes formation of a depot at the site of injection from which antigen is released slowly; stimulation of immune-competent cells of the body through activation of complement, induction of eosinophilia, and activation of macrophages; and efficient uptake of aluminum-adsorbed antigen particles by antigen-presenting cells because of their particulate nature and optimal size (< 10 microns). Limitations of aluminum adjuvants include local reactions, production of IgE antibodies, ineffectiveness for some antigens, and inability to elicit cell-mediated immune responses especially cytotoxic T-cell responses. Calcium phosphate, which has adjuvant properties similar to aluminum adjuvants, has the potential advantages of being a natural component of the body and of not increasing IgE production. There is a need for alternative adjuvants, particularly for diseases in which cell-mediated immune responses are important for prevention or cure.

Immunoglobulin E and G responses to pertussis toxin after booster immunization in relation to atopy, local reactions and aluminium content of the vaccines

The role of aluminium for IgG and IgE responses to pertussis toxin (PT), as well as for side effects, was investigated in 49 children with known atopy status. Primary immunization had been given with an adsorbed monocomponent or an adsorbed two-component acellular pertussis vaccine. The children were then randomized to receive a booster immunization with either aluminium-adsorbed or non-adsorbed, whole cell, pertussis vaccine. Both vaccines induced good IgG responses with the adsorbed vaccine giving higher post-booster levels (p < 0.05). The adsorbed vaccine was, however, associated with more local side effects (p < 0.05) and tended to induce higher PT-IgE responses than the non-adsorbed vaccine. Furthermore, individuals who had received the two-component vaccine as primary immunization had higher PT-IgE responses after the booster, compared with individuals initially receiving the monocomponent vaccine (p = 0.041). No correlation between PT-IgE and PT-IgG levels was seen in any of the groups. Total serum IgE levels correlated to PT IgE levels, particularly in children with atopy (r = 0.950, p < 0.001). The addition of aluminium to the pertussis vaccine, was, thus, associated with a stronger IgG antibody response, but tended also to induce a stronger IgE antibody response. The correlation between total IgE and PT-IgE, which was most prominent in children with atopy, indicates that the role of immunization for the development of allergy merits further studies.

Adverse reactions after diphtheria-tetanus booster in 10-year-old schoolchildren in relation to the type of vaccine given for the primary vaccination

This prospective open study investigated adverse reactions in 527 schoolchildren to a diphtheria-tetanus (DT) booster given within a national vaccination programme at 10 years of age. Evaluation was based on those whose immunization records showed that they had received either three doses of an adsorbed DT vaccine (n = 388) or a non-adsorbed DT-pertussis vaccine (DTP) (n = 69) for primary series vaccination. No differences in systemic reactions to the booster between the two groups were observed. Local reactions were significantly (p < 0.001) more common 1 day after vaccination in children who had received DT for primary series vaccination: redness, 73% compared with 23%; swelling, 56% versus 15%; and itching, 47% versus 21%. One and 2 weeks after the booster, itching was still more pronounced in the group who had received DT for primary series vaccination (p < 0.001 and 0.014, respectively). The study indicates that there was a real basis for the increase in spontaneous notifications of local side-effects to the school DT booster in Sweden. The most likely cause for the increase seems to be the aluminium adjuvant in the vaccine given for primary vaccination, a late and unexpected consequence of a change in the infant immunization programme.

Enhancement of interleukin-4 production by pertussis toxin

Pertussis toxin (PT), a protein toxin of Bordetella pertussis, has many biological activities, including potent adjuvant capacity and the ability to up-regulate immunoglobulin E (IgE) production. Interleukin-4 (IL-4) is a cytokine which is essential for the IgE response. Accordingly, we examined the effect of PT on IL-4 production. Spleen and lymph node cell suspensions were prepared from immunized mice and cultured with antigen or polyclonal stimuli in vitro. IL-4 secretion was assessed by bioassay, and IL-4 mRNA expression was assessed by reverse transcription and polymerase chain reaction. Significantly larger amounts of IL-4 protein and mRNA were produced in vitro by cells from mice given PT at the time of immunization than by cells from mice given antigen alone, PT alone, or the combination of antigen with cyclophosphamide. Total and antigen-specific serum IgE levels were significantly elevated in immunized mice given PT, compared with the other groups. Thus, there was a relationship between serum IgE and IL-4 production. The administration of a single dose of an anti-IL-4 monoclonal antibody in vivo, at the time of immunization and treatment with PT, abolished the development of the IgE response. These results indicate that PT is a potent stimulus for the production of IL-4, which is required for the adjuvant effect of PT on IgE formation.

Prediction and detection of allergy development: influence of genetic and environmental factors

The prevalence of atopic diseases is increasing in northwestern Europe and probably also in the rest of the Western world. Detecting cord blood IgE, in combination with obtaining a family history of atopic disease, seems to be the most valuable method of predicting all forms of atopic disease; however, this will identify only a small proportion of children with subsequent development of atopic disease. Determination of cord blood IgE cannot, without modifications, be recommended as a single test for identifying infants for allergy prevention programs. Skin prick reaction to egg white during the first year of life seems to identify a majority of children in whom allergic disease is going to develop during infancy. Other methods, such as genetic markers of an atopic constitution, eventually may facilitate early identification of infants at risk of atopic disease.

Lymphokine secretion and cytotoxic activity of human CD4+ T-cell clones against Bordetella pertussis

Human CD4+ T-cell clones specific for pertussis toxin and other Bordetella pertussis antigens have been tested for their cytotoxic activity, lymphokine production, and capacity to induce immunoglobulin synthesis. Clones specific for the S1 subunit of pertussis toxin were cytotoxic for autologous Epstein-Barr virus-transformed B cells, which had been pulsed with the native antigen, the recombinant S1 subunit of pertussis toxin, or synthetic peptides derived from the S1 amino acid sequence. The killing of antigen-pulsed target cells was class II restricted. All of the T-cell clones produced mostly interleukin-2 and gamma interferon and assisted allogeneic B cells in the production of immunoglobulins M and G but not immunoglobulin E. The potential in vivo role of the cytotoxic activity of these clones is discussed.

Adverse reactions after injection of adsorbed diphtheria-pertussis-tetanus (DPT) vaccine are not due only to pertussis organisms or pertussis components in the vaccine

Reactions to adsorbed diphtheria-pertussis-tetanus (DPT) vaccine have mostly been attributed to the pertussis organisms or pertussis components in the vaccine. Nevertheless reactions may also be due to other factors such as sensitization induced by aluminium adjuvants and impurities present in crude toxoids that cannot be removed by purification of toxoids after formalinization. Aluminium compounds such as aluminium phosphate and aluminium hydroxide are the most commonly used adjuvants with vaccines for human use. Due to the increasing concern about the toxicity of aluminium, other adjuvants like calcium phosphate may be evaluated as an alternative to aluminium adjuvants. To minimize reactions after immunization with DPT vaccine due to impurities in the toxoids, the use of toxoided purified toxins is suggested.

IgE: an immunoglobulin specialized in antigen capture?

IgE bound to the low-affinity receptor for immunoglobulin E (Fc epsilon R) on antigen-presenting cells (APCs) may permit binding of antigens to APCs prior to their processing and presentation. Here, G. C. Mudde and colleagues argue that the unique characteristics of IgE serological responses together with the distribution of Fc epsilon RII (CD23) on APCs are consistent with this novel function of IgE. The concept of IgE involvement in antigen capture is discussed in relation to Langerhans cells, B cells and follicular dendritic cells.