Impact of genetic variants in IL-4, IL-4 RA and IL-13 on the anti-pneumococcal antibody response

BACKGROUND

Significant differences in immune responses upon vaccination have been described, suggesting genetics are important in determining the magnitude of vaccine responses. The interleukin (IL)-4 pathway, including IL-4, IL-13 and the IL-4 receptor alpha chain (IL-4 Ralpha), is central to humoral responses and therefore could have an impact on vaccine responsiveness.

OBJECTIVE

To investigate whether single nucleotide polymorphisms (SNPs) in the IL-4, IL-13 and IL-4 RA genes influence pneumococcal serotype-specific IgG antibody responses.

METHODS

SNPs in the IL-4 gene (C -589T, G2979T), the IL-13 gene (G -1112A, Arg130Gln) and in the IL-4 RA gene (Ile50Val, Gln551Arg) were investigated in isolation and in combination, for their influence on serotype-specific IgG antibody responses upon combined pneumococcal conjugate and polysaccharide vaccinations in children with a history of recurrent otitis media.

RESULTS

Lower antibody responses were observed for alleles previously associated with atopy, IL-4 -589T, IL-4 2979T and IL-4 Ralpha 551Gln. Effects were stronger in gene haplotype combinations or in multiple haplotype combination analyses.

CONCLUSION

This study highlights the importance of host genetic factors in vaccine responses. Furthermore, it supports the approach of studying the effect of combinations of multiple alleles, in haplotypes or in combinations of haplotypes, on complex phenotypes within a biological pathway.

Association of CD14 promoter polymorphism with otitis media and pneumococcal vaccine responses

Innate immunity is of particular importance for protection against infection during early life, when adaptive immune responses are immature. CD14 plays key roles in innate immunity, including in defense against pathogens associated with otitis media, a major pediatric health care issue. The T allele of the CD14 C-159T polymorphism has been associated with increased serum CD14 levels. Our objective was to investigate the hypothesis that the CD14 C-159T allele is protective against recurrent acute otitis media in children. The association between the CD14 promoter genotype and the number of acute otitis media episodes was evaluated both retrospectively and prospectively in a cohort of 300 children. Serotype-specific immunoglobulin G (IgG) antibody responses after pneumococcal vaccinations were examined according to CD14 genotype to compare immune responsiveness across genotypes. An age-dependent association was found: compared with that for CC homozygotes aged between 12 to 24 months, TT homozygotes had fewer episodes of acute otitis media (79 versus 41%, respectively; P = 0.004); this relationship was absent in older children. Additionally, TT homozygotes showed higher serotype-specific anti-pneumococcal IgG antibody levels. Our data suggest that genetic variation in CD14, a molecule at the interface of innate and adaptive immune responses, plays a key role in the defense against middle ear disease in childhood and in pneumococcal vaccine responsiveness. These findings are likely to be important to these and other immune-mediated outcomes in early life.

Primary care management of respiratory tract infections in Dutch preschool children

OBJECTIVE

To determine age-specific antibiotic prescription and referral rates in preschool children diagnosed with acute respiratory tract infection (RTI) in primary care.

DESIGN

Retrospective cohort study.

SETTING

Research database of the Netherlands University Medical Center Utrecht Primary Care Network.

SUBJECTS

All children aged 0-5 years within the database were included, covering 1998 to 2002 (18,801 child-years).

MAIN OUTCOME MEASURES

Antibiotic prescription and referral rates were determined as percentage of children with at least one prescription or referral within a year, as total number of prescriptions per 1000 child-years, and as percentage of all RTI episodes.

RESULTS

Antibiotics, mostly beta-lactam (80%) and macrolides (16%), were prescribed in 35% of RTI episodes. Annually 13% of the children received at least one antibiotic following an RTI. Antibiotics were prescribed in more than half of episodes of LRTI, sinusitis, AOM, and acute tonsillitis, and in 12-15% of episodes of asthma exacerbation, acute laryngitis, influenza acute, and acute upper respiratory infection (including common cold and pharyngitis). Almost 98% of RTIs were managed in primary care. On average 1% of the children were referred to a paediatrician or ENT specialist following RTI per year, especially after AOM (59% of referrals). Compared with older children, those under two years of age were more often treated with antibiotics (relative risk [RR] 1.4, 95% CI 1.3-1.6) and referred (RR 2.3; 95% CI 1.8-3.0).

CONCLUSION

In the Netherlands most episodes of RTIs in preschool children were managed in primary care and this often involves prescription of antibiotics. Children younger than two years of age receive more often antibiotics for RTI and are also referred more, especially for AOM.

Long-term effects of pediatric adenotonsillectomy on serum immunoglobulin levels: results of a randomized controlled trial

BACKGROUND

It remains controversial whether pediatric adenotonsillectomy ultimately results in decreased serum immunoglobulin levels and if so whether such a decrease is associated with increased susceptibility to upper respiratory tract infections (URIs).

OBJECTIVE

To evaluate changes in serum immunoglobulin levels in relation to occurrence of URIs in children participating in a randomized controlled trial on the effectiveness of adenotonsillectomy.

METHODS

A total of 300 children aged 2 to 8 years, with symptoms of recurrent throat infections or tonsillar hypertrophy, were randomly assigned to either adenotonsillectomy or watchful waiting (WW). Serum samples were collected at baseline and at 1-year follow-up. Occurrence of throat infections and other URIs during first-year follow-up was recorded in a diary by the child's parents.

RESULTS

Paired serum samples were available for 123 children (63 in the adenotonsillectomy group and 60 in the WW group). IgG1 and IgG2 levels decreased but remained within the reference range for age in both study arms. IgM and IgA levels decreased as well but remained elevated. The IgA level in the adenotonsillectomy group decreased in significantly greater degree compared with the WW group, but this difference disappeared in cases where children experienced frequent URIs. In general, no relation between immunoglobulin levels and the number of throat infections or URIs at 1-year follow-up was found.

CONCLUSIONS

Immunoglobulin levels of children undergoing adenotonsillectomy decreased from elevated to slightly elevated or reference values for age during 1-year follow-up irrespective of treatment (adenotonsillectomy or WW). IgA showed a greater decrease in the adenotonsillectomy group but rose to levels comparable with the WW group in cases of frequent URIs. This finding indicates that the remaining mucosa-associated lymphoid tissue can compensate for the loss of tonsil and adenoid tissue.

Prediction of asthma in young adults using childhood characteristics: Development of a prediction rule

OBJECTIVE

To develop an easily applicable prediction rule for asthma in young adulthood using childhood characteristics.

METHODS

A total of 1,055 out of 1,328 members of a Dutch birth cohort were followed from 2 to 21 years of age. Univariate and multivariate logistic regression analyses were used to evaluate the predictive value of childhood characteristics on asthma at 21 years of age. A prognostic function was developed, and the area under the receiving operating characteristic (ROC) curve was used to estimate the predictive ability of the prognostic models.

RESULTS

Of the 693 responding subjects, 86 (12%) were diagnosed with asthma. Independent prognostic factors at ages 2 and 4 years were female gender (odds ratios (OR) 1.9 and 2.1; 95% confidence intervals (CI) 1.2-3.2 and 1.3-2.5), smoking mother (OR 1.6 and 1.6; CI 1.0-2.7 and 1.0-2.6), lower respiratory tract illness (OR 1.9 and 2.4; CI 1.0-3.6 and 1.4-4.0), and atopic parents (OR 2.1 and 1.9; CI 1.3-3.4 and 1.2-3.1). The predictive power of both models was poor; area under ROC curve was 0.66 and 0.68, respectively.

CONCLUSION

Asthma in young adulthood could not be predicted satisfactorily based on childhood characteristics. Nevertheless, we propose that this method is further tested as a tool to predict development of asthma.

Recurrent childhood upper respiratory tract infections do not reduce the risk of adult atopic disease

BACKGROUND

Children of large families and those attending day care are at increased risk of respiratory tract infections, which in turn may protect against the development of allergic disease. Longitudinal studies investigating these associations beyond childhood are, however, scarce.

OBJECTIVE

To investigate the association between childhood recurrent upper respiratory tract infections (URTI) and asthma, allergic rhinitis (AR) and eczema in adulthood.

METHODS

A birth cohort of 1055 members followed prospectively from the ages of 2 to 21 years. Detailed information on URTI between the ages of 2 and 4 years was collected at 3 monthly intervals in a standardized interview. At the age of 8 years, a parental questionnaire regarding URTI between the ages of 4 and 8 years was used. The incidence of asthma and atopic disease at the age of 21 years was determined using a standardized questionnaire.

RESULTS

Of the original cohort, 693 (66%) members completed the questionnaire. Children who experienced recurrent URTI before the age of 2 years, between the ages of 2-4 years and between ages of 4 and 8 years were not less likely to have asthma at 21 years of age than children who did not experience recurrent URTI, relative risk (RR) 0.97 (95% confidence interval (CI) 0.65-1.46), RR 1.45 (CI 0.95-2.21) and RR 1.51 (CI 0.97-2.36), respectively. Neither were recurrent URTI associated with a decreased risk of AR, nor eczema at the age of 21 years.

CONCLUSIONS

Recurrent URTI in childhood did not reduce the risk of atopic disease in young adulthood.

Influence of sampling technique on detection of potential pathogens in the nasopharynx

OBJECTIVES

To determine the optimal approach for nasopharyngeal culture and to establish which approach children tolerate best.

DESIGN

Cross-sectional study.

SETTING

A pediatric otolaryngology department of a Dutch tertiary care hospital.

PATIENTS

A cohort of 42 children with chronic suppurative otitis media.

INTERVENTION

Paired nasopharyngeal samples were collected transorally and transnasally and cultured for potential aerobic pathogens.

MAIN OUTCOME MEASURES

The isolation rate of both samples and the amount of discomfort measured by the visual analog scale.

RESULTS

Forty-six (87%) of 53 samples obtained transnasally were culture positive vs 40 (75%) of 53 samples obtained transorally (P = .20). Streptococcus pneumoniae, Haemophilus influenzae, Moraxella catarrhalis, and Staphylococcus aureus were found more frequently with the transnasal than with the transoral approach: 34% vs 13% (P = .003), 62% vs 51% (P = .20), 30% vs 19% (P = .15), and 21% vs 11% (P = .18), respectively. Mean (SD) visual analog scale scores were 5.3 (1.0) and 3.4 (1.7) (P<.001) for the transnasal and transoral approaches, respectively.

CONCLUSIONS

Although the transoral approach is better tolerated in children, the isolation rate of the transnasal approach is higher, especially for S. pneumoniae. The transnasal sampling technique should therefore be the preferred approach for detection of potential pathogens in the nasopharynx in children.

Loss of antibodies and response to (re-)vaccination in children after treatment for acute lymphocytic leukemia: a systematic review

Intensified chemotherapy regimens resulting in improved survival of children with acute lymphocytic leukemia (ALL) lead to concerns about therapy-induced immune damage reflected by the loss of protection of previous immunizations and the efficacy of (re-)vaccination. The severity of secondary immunodeficiency, however, is not clear and knowledge is based on a limited number of studies. We performed a systematic review on literature concerning vaccination data of children with ALL published since 1980. Eight studies fulfilled the inclusion criteria. Regarding antibody titers after treatment, the number of children who had preserved the defined protection level for antibodies differed widely, ranging from 17 to 98% for diphtheria, 27 to 82% for Bordetella pertussis, 20 to 98% for tetanus, 62 to 100% for poliomyelitis, 35 to 100% for Haemophilus influenzae type B (HiB), 29 to 92% for mumps, 29 to 60% for measles and 72 to 92% for rubella. Most patients however responded to revaccination, demonstrating immunological recovery. Although the designs and results of the included studies varied widely, it can be concluded that cytostatic therapy for ALL in children results in a temporarily reduction of specific antibody levels. Memory is preserved but revaccination may be warranted. This is the first systematic review and the best possible current approximation of chemotherapy-induced immune damage in children after ALL treatment.

Mannose-binding lectin and upper respiratory tract infections in children and adolescents: a review

OBJECTIVE

To review the literature on mannose-binding lectin (MBL) polymorphisms and susceptibility for upper respiratory tract infection (URI) in children and adolescents.

DATA SOURCES

We searched PubMed from 1966 and EMBASE from 1974 to July 2005, using the terms respiratory tract infection, respiratory infection, upper respiratory infection, MBL, and mannose-binding lectin.

STUDY SELECTION

Initially, 110 studies were identified. Two reviewers independently screened identified titles and abstracts. Potentially relevant studies were obtained and the full text examined. Inclusion criteria were human subjects, 18 years or younger, URI, and MBL polymorphisms. Seven of the initially identified studies met the inclusion criteria.

DATA EXTRACTION

Information was gathered for each study on study design, population, possible confounders, and outcomes measured.

DATA SYNTHESIS

Because there was significant heterogeneity between the identified studies, we had to describe the identified studies separately. The largest case-control studies (n = 3) as well as the cohort study (n = 1) suggest an association between MBL polymorphisms and URI, especially in young children. Results of the smaller studies (n = 3) are inconsistent.

CONCLUSIONS

The association between MBL polymorphisms and URI in children remains controversial. Large prospective cohort studies with regular documentation of URI and possible confounders such as atopy and environmental factors are required to establish the role of MBL polymorphisms in susceptibility for URI.

Persistence of upper respiratory tract infections in a cohort followed from childhood to adulthood

OBJECTIVE

To assess (1) prevalences of recurrent URTIs (rURTIs) and relapsing/persistent rURTIs and associated medical consumption between 0 and 21 years of age and (2) whether rURTIs experienced in early life predispose to upper airway disease later in life.

METHODS

A cohort of all children born in Nijmegen, The Netherlands, between September 1982 and September 1983, was assessed repeatedly from 2 to 21 years of age with questionnaires regarding infections of the upper respiratory tract (URTIs), use of antibiotics, ENT operations and known risk factors for URTIs.

RESULTS

One hundred and sixty-one of the 693 cohort member (23%) suffered from relapsing rURTIs between 0 and 21 years of age, whereas only 7 (1%) suffered from persistent rURTIs throughout this period. Two hundred and six (30%) had used antibiotics more than once; and 220 (32%) had undergone at least one ENT operation. Of the 166 participants with rURTI between 8 and 21 years, 140 (84%) had had rURTI before.

CONCLUSIONS

rURTIs are highly prevalent throughout early life and associated medical consumption is substantial. The challenge therefore is to develop therapeutic/preventive strategies that will prevent rURTIs in the first years of life.

Functional polymorphisms in the mannan-binding lectin 2 gene: Effect on MBL levels and otitis media

BACKGROUND

Mannan-binding lectin (MBL) can bind to microorganisms, initiating the lectin pathway of complement activation. Aberrant MBL serum levels, caused by MBL2 gene polymorphisms, are a possible risk factor for recurrent infections. Within the 7 common MBL haplotypes, still considerable variation in MBL serum levels exists.

OBJECTIVE

To investigate functional MBL levels and MBL2 polymorphisms in a large cohort of children with recurrent acute otitis media.

METHODS

Twelve genetic variants in the MBL2 gene and functional MBL serum levels were determined in a cohort of children with recurrent acute otitis media. Haplotypes were constructed and associated with functional MBL serum levels and the number of otitis episodes in the previous year.

RESULTS

The 7 common MBL2 haplotypes mainly determine the level of functional MBL in serum. In addition, the 3130G>C single nucleotide polymorphism, located in exon 4, further significantly influenced functional MBL levels within the LXPA haplotype. LXPA carriers with 3130G showed a significantly lower geometric mean functional MBL serum level of 0.19 mug/mL compared with 0.70 mug/mL in 3130C carriers (P = .026). Nonwild-type MBL2 carriers between 12 and 24 months had a significantly increased number of otitis episodes (5.1/y) compared with wild-type MBL2 carriers (4.1/y; P = .027). In older children, this association was not found anymore.

CONCLUSION

Additional single nucleotide polymorphisms within the 7 common haplotypes can further explain the observed variation in functional MBL serum levels. MBL seems to be of particular clinical importance during early childhood, when maternally derived antibodies have waned, and protective adaptive immunity is not well developed yet.

CLINICAL IMPLICATIONS

Single nucleotide polymorphisms in the promoter region, in exon 1, and in exon 4 of MBL2 contribute to increased risk for otitis media in children younger than 2 years.

Advances in understanding the pathogenesis of pneumococcal otitis media

In this review, a state of the art on otitis media research is provided with emphasis on the role of Streptococcus pneumoniae in the pathogenesis of this disease. Articles have been selected by MEDLINE search supplemented with a manual crosscheck of bibliographies. Pathogenic mechanisms in middle ear and eustachian tube are described. Furthermore, pneumococcal characteristics and pneumococcus-host interactions are highlighted as well as the possible role of biofilms in persistence or recurrence of otitis media. Because of the availability of new techniques, an increasing number of pneumococcal features contributing in the pathogenesis of otitis media are identified and in-depth knowledge of pneumococcus-host interactions has been gained. The present advances in research on otitis media open up new perspectives for therapeutic or preventive strategies.

Optimal site for throat culture: tonsillar surface versus posterior pharyngeal wall

To determine the optimal site of throat culture for the detection of potential pathogens by comparing culture results from the tonsillar surface and the posterior pharyngeal wall in children selected for adenotonsillectomy and in children without upper respiratory disease. Cotton culture swabs were taken from the tonsillar surface and the posterior pharyngeal wall of 50 children selected for adenotonsillectomy for symptoms of recurrent tonsillitis and/or adenotonsillar hypertrophy and of 50 children without upper respiratory disease. Potential respiratory pathogens were identified. In the overall group (n = 100), positive culture results were found in 67 posterior pharyngeal wall samples and 47 tonsillar surface samples (P = 0.001). Haemophilus influenzae was the most frequently isolated micro-organism both in the posterior pharyngeal wall and the tonsillar surface samples; 55 and 35%, respectively (P = 0.001). Group A beta-haemolytic streptococci were found in the samples of the posterior pharyngeal wall and the tonsillar surface in 17 and 13%, respectively (P = 0.2). When dealing with patients with sore throat, sampling both tonsillar surfaces is enough for the detection of group A beta-haemolytic streptococci. When detection of other bacteria is also important, such as for research purposes, the posterior pharyngeal wall should be sampled as well.

Effect of combined pneumococcal conjugate and polysaccharide vaccination on recurrent otitis media with effusion

BACKGROUND

Otitis media with effusion (OME) is very common during childhood. Because Streptococcus pneumoniae is one of the most common bacterial pathogens involved in OME, pneumococcal vaccines may have a role in the prevention of recurrent OME.

OBJECTIVE

We sought to assess the effect of combined pneumococcal conjugate and polysaccharide vaccinations on the recurrence of OME.

METHODS

A randomized, controlled trial was performed with 161 children, 2 to 8 years of age, with documented persistent bilateral OME. All subjects were treated with tympanostomy tubes (TTs). One half of the subjects were assigned randomly to additional vaccination with a 7-valent pneumococcal conjugate vaccine 3 to 4 weeks before and a 23-valent pneumococcal polysaccharide vaccine 3 months after tube insertion. Blood samples were drawn at the first vaccination, at the time of TT placement, and 1 and 3 months after the second vaccination. Levels of IgA and IgG serum antibody against the 7-valent pneumococcal conjugate vaccine serotypes 4, 6B, 9V, 14, 18C, 19F, and 23F were measured with enzyme-linked immunosorbent assays. All children were monitored for recurrence of OME for 6 months after spontaneous extrusion of the TTs.

RESULTS

The overall recurrence rate of bilateral OME was 50%. Pneumococcal vaccinations induced significant 4.6- to 24.4-fold increases in the geometric means of all conjugate vaccine serotype antibody titers but did not affect recurrence of OME.

CONCLUSIONS

Combined pneumococcal conjugate and polysaccharide vaccination does not prevent recurrence of OME among children 2 to 8 years of age previously known to have persistent OME. Therefore, pneumococcal vaccines are not indicated for the treatment of children suffering from recurrent OME.

Pneumococcal conjugate vaccination in children with recurrent acute otitis media: a therapeutic alternative?

BACKGROUND

Based on two clinical trials in healthy infants the American Academy of Pediatrics (AAP) advices immunization with a 7-valent pneumococcal conjugate vaccine in children with recurrent acute otitis media (AOM).

OBJECTIVE

To study the efficacy of a 7-valent pneumococcal conjugate vaccine on acute otitis media recurrences, its immunogenicity and impact on nasopharyngeal Streptococcus pneumoniae carriage in children with a history of frequent acute otitis media.

METHODS

In this double-blind, randomized study, 74 Belgian children, aged 1-7 years, with at least 2 clinically diagnosed episodes of acute otitis media in the previous year were enrolled. Children were immunized with either a 7-valent pneumococcal conjugate vaccine followed by a 23-valent pneumococcal polysaccharide booster or a control hepatitis A vaccine. Total follow-up was 26 months.

RESULTS

Despite adequate serum IgG responses to all conjugate vaccine pneumococcal serotypes, no reduction of acute otitis media episodes was observed in the pneumococcal vaccine group as compared to the control group (rate ratio: 1.16; 95% CI: 0.69-1.96). Overall nasopharyngeal pneumococcal carriage remained stable. However, a transient shift from conjugate vaccine related S. pneumoniae serogroups to non-vaccine related serogroups was noted following conjugate vaccination.

CONCLUSION

Clinically no protective effect of pneumococcal conjugate vaccination on acute otitis media recurrences was found in children with a history of frequent AOM.

Pneumococcal vaccine efficacy for mucosal pneumococcal infections depends on Fcγ receptor IIa polymorphism

IgG2 antibodies are the main antibody subclass produced after pneumococcal polysaccharide vaccination. For these antibodies to be effective, interaction with FcgammaIIa receptors on phagocytic cells is necessary. FcgammaRIIa displays a functional polymorphism with either a histidine (H) or arginine (R) at position 131. Interaction of IgG2 antibodies depends on the H131 allele, whereas this interaction is low to absent with the R131 allele. We tested the clinical efficacy of combined pneumococcal conjugate and pneumococcal polysaccharide vaccination according to FcgammaIIa-H/R131 genotype in a randomized double blind placebo controlled vaccination trial in children with a history of acute otitis media. We found a decisive role for the FcgammaIIa-H/R131 polymorphism on the clinical vaccine efficacy of combined pneumococcal conjugate and polysaccharide vaccinations. RR homozygotes showed a significant increase in recurrence of acute otitis media after pneumococcal vaccinations. This cannot be explained by differences in the pneumococcal specific antibody response or differences in nasopharyngeal pneumococcal carriage, but may be explained by less efficient interaction of FcgammaRIIa with polysaccharide-induced IgG2 anti-pneumococcal antibodies in RR homozygotes. Our data show that the genetic make-up of individuals or populations under study should be considered while evaluating vaccine efficacy trials.

Chronic suppurative otitis media: a review

OBJECTIVES

Chronic suppurative otitis media (CSOM) remains one of the most common childhood chronic infectious diseases worldwide. Although microbial, immunological, and genetically determined factors, as well as Eustachian tube characteristics, are supposed to be involved in the pathogenesis of CSOM, many aspects of the pathogenesis of CSOM still need to be clarified. Optimal treatment strategy has not been established yet. The objective of this review is to present and evaluate the current state of knowledge of CSOM.

DESIGN

Systematic narrative review.

METHODS

A PubMed search (1966-January 2005) was performed for studies on epidemiology, pathogenesis, clinical management, and complications of CSOM. All included articles were categorized according to level of evidence.

RESULTS

Five hundred and fifty papers were identified, of which 79 were found to be relevant for this review. The definition of CSOM was found to vary. CSOM is a multifactorial disease. Regarding management of CSOM, there is no consensus as to what the optimal management strategy should entail. No convincing evidence is available for most medical and surgical therapies. Topical quinolones have proven effective, but need further monitoring regarding adverse effects.

CONCLUSIONS AND RECOMMENDATIONS

Important goals in research of CSOM should be achieving consensus about the definition of CSOM and gaining more in-depth knowledge of the pathogenesis of CSOM, especially the role of innate and adaptive immunity. There is also a need for further well-designed studies on the effectiveness of various management strategies for CSOM.

Rationale and design of the prevention of respiratory infections and management in children (PRIMAKid) study: a randomized controlled trial on the effectiveness and costs of combined influenza and pneumococcal vaccination in pre-school children with recurrent respiratory tract infections

Health and economic burden of recurrent respiratory tract infections (RTIs) in early childhood is considerable. A systematic review of licensed influenza and pneumococcal vaccines showed substantial efficacy in children, but the health-economic impact of such vaccines among pre-school children with recurrent RTIs is unknown. We therefore, designed a double-blind randomized controlled trial to determine the effectiveness and costs of a combined influenza and pneumococcal vaccination program among a primary care based cohort of children with recurrent episodes of RTI aged between 18 and 72 months. We will enroll 690 children over three consecutive years (2003--2005) who will be randomly allocated to receive vaccinations against influenza and pneumococcal disease, influenza alone or hepatitis B in a similar schedule. Follow up by parental diaries, tympanic temperature measurements, questionnaires and interviews is planned until May 2006. Primary outcome is number of febrile RTIs. Other outcomes include duration and severity of RTI episodes, medical consumption, safety and costs.

Immunologic screening of children with recurrent otitis media

Some 5% to 10% of all infants and toddlers suffer from four or more episodes of otitis per year. Usually, this is a temporary problem that resolves with increasing age. In a minority of cases, otitis episodes are frequent or have an abnormal course, with complications such as mastoiditis. In these cases, immunologic screening is indicated, to exclude an immunodeficiency. Agammaglobulinemia or hypogammaglobulinemia is rare among these patients. Other immune defects that occur more often are deficient or lowered immunoglobulin (Ig)A or decreased levels of one or more IgG subclass, in particular IgG2. The specific antibody response to bacterial capsular polysaccharides often is disturbed. These findings can give direction to the treatment of children with frequent, recurrent otitis.

Immunological status in the aetiology of recurrent otitis media with effusion: serum immunoglobulin levels, functional mannose-binding lectin and Fc receptor polymorphisms for IgG

The objective was to study the role of serum immunoglobulin levels, mannose-binding lectin (MBL), and Fc gamma receptor (FcgammaR) polymorphisms on the development of recurrent otitis media with effusion (OME). Children aged between two and seven years with persisting OME received bilateral tympanostomy tubes and immunological parameters were investigated in relation with OME recurrence within six months after tube extrusion. No statistically significant differences in serum immunoglobulin levels were present between children with and without OME recurrence. In children with bilateral recurrence (n = 56), median levels of MBL were 1.39 mg/L compared to 2.48 mg/L in children with OME recurrence (n = 17) (p = 0.29). In addition, 34% of the children with bilateral recurrence were homozygous for the genotype FcgammaRIIa-R/R131, whereas less than 20% of the children with unilateral recurrence or those without recurrence were homozygous for this Fcgamma receptor (p = 0.26). Serum mannose-binding lectin and FcgammaRIIa-R/R131 polymorphism may play a role in the aetio-pathogenesis of recurrent OME.

The impact of recurrent acute otitis media on the quality of life of children and their caregivers

OBJECTIVE

To assess the quality of life of 384 Dutch children aged 1-7 years with recurrent acute otitis media (AOM), and compare it with that of children from four reference populations: (i) children from a general population; (ii) children with mild-to-moderate asthma, (iii) children with mild-to-moderately severe chronic illness, and (iv) US children with persistent or recurrent otitis media.

DESIGN

Survey.

SETTING

A general and an academic hospital (study population of children with recurrent AOM, n = 384); general population (n = 225 and 117); primary care (children with asthma, n = 64); community care (children with chronic illness, n = 82); and a general hospital (children with persistent or recurrent otitis media, n = 169).

PARTICIPANTS

A total of 384 children aged 1-7 years who had experienced at least two episodes of AOM in the preceding year and their caregivers.

MAIN OUTCOME MEASURES

Generic and disease-specific quality of life as judged by the children's caregivers. Age-adjusted total and subscale scores were compared with those of the reference populations.

RESULTS

For all generic questionnaires, children with recurrent AOM had poorer scores than children from the general population. Quality of life of children with four or more episodes of AOM in the preceding year was poorer than that of children with two to three episodes. Children with recurrent AOM scored lower on the health-related questionnaire than children with mild-to-moderately severe chronic illness. Quality of life of the present study population was similar to those of children with asthma and US children with chronic otitis media with effusion or recurrent AOM.

CONCLUSION

Recurrent AOM has a considerable negative impact on the quality of life of children and causes concern to their caregivers. These effects are proportional to the severity of the condition. Professionals involved in the care of children with OM should be aware that OM not only affects physical functioning but also general well-being of the child and its family. These outcomes should therefore be included in the evaluation of the child with otitis media both in the clinical and research setting.

Involvement of glycosaminoglycans in the attachment of pneumococci to nasopharyngeal epithelial cells

Streptococcus pneumoniae is a major bacterial pathogen involved in the development of otitis media. The pathogenic mechanisms of this middle ear disease, including the bacterial adherence mechanisms to the mucosal epithelial cells of the host, are poorly understood. In this study, the role of glycosaminoglycans in the adhesion of pneumococci to mucosal epithelial cells is examined. Both nasopharyngeal epithelium from rats and an oral epithelial cell line were used for pneumococcal adherence experiments. Preincubation of pneumococci with heparin, heparan sulfate (HS) and to a lesser extent, chondroitin 4-sulfate (C-4S), was found to inhibit attachment of S. pneumoniae to oral epithelial cells, while dermatan sulfate and hyaluronate did not interfere with pneumococcal binding. Enzymatic removal of HS moieties by heparinase III from nasopharyngeal epithelial cells abolished the attachment of pneumococci to nasopharyngeal epithelium. This study demonstrates that heparin, HS and C-4S are involved in pneumococcal binding to mucosal epithelial cells. This knowledge may contribute to the development of a new prophylactic strategy for otitis media.

Immune Status and Eustachian Tube Function in Recurrence of Otitis Media With Effusion

OBJECTIVE

To study the combined role of immune status and eustachian tube function in the development of recurrent bilateral otitis media with effusion (OME).

DESIGN

Prospective cohort study.

SETTING

Three academic and general hospitals.

PATIENTS

Children aged 2 to 7 years with a first clinical episode of bilateral OME that persisted for at least 3 months; 136 (81%) of 168 eligible children participated. All children received bilateral tympanostomy tubes at study entry.

MAIN OUTCOME MEASURE

Recurrence of bilateral OME within 6 months after tube extrusion.

RESULTS

Univariate analyses of various immunologic factors (IgA, IgG1, IgG2, IgG3, IgG4, mannose-binding lectin, and the FcgammaRIIa-H/R131 genotype) and eustachian tube function (forced response test) did not show any significant associations with bilateral OME recurrence. Multivariate analyses showed that children with closing pressures higher than the 75th percentile and IgA or IgG2 levels below the 50th percentile of the cohort were more likely to develop recurrent OME than children with closing pressures higher than the 75th percentile and IgA or IgG2 levels above the 50th percentile. The corresponding risk ratios were 6.3 (95% confidence interval [CI], 1.0-40.1) for IgA level and 3.0 (95% CI, 1.1-8.2) for IgG2 level. The multivariate analyses also revealed that increasing serum levels of functional mannose-binding lectin were associated with decreasing probabilities of developing recurrent OME (odds ratio, 0.7; 95% CI, 0.6-1.0).

CONCLUSION

Recurrence of bilateral OME after tympanostomy tube placement is more likely in children with a combination of low IgA or low IgG2 levels with poor eustachian tube function and decreased levels of mannose-binding lectin.

Disease modifying genes in cystic fibrosis

The variation in cystic fibrosis (CF) lung disease and development of CF related complications correlates poorly with the genotype of the CF transmembrane regulator (CFTR) and with environmental factors. Increasing evidence suggests that phenotypic variation in CF can be attributed to genetic variation in genes other than the CFTR gene, so-called modifier genes. In recent years, multiple candidate modifier genes have been investigated in CF, especially genes that are involved in the control of infection, immunity and inflammation. Some of these genes have been rather conclusively identified as modifiers of the CF phenotype, whereas associations found in other genes have not been confirmed or are conflicting. Identification of genetic variation in modifier genes, obtained by genotype-phenotype studies in well-defined patient populations, may be used as an aid to prognosis and may provide the possibility of new therapeutic interventions.

Health-related quality of life in children with otitis media

BACKGROUND

Growing interest in health-related quality of life (HRQoL) in children with otitis media has brought the need to study the currently available HRQoL instruments with respect to their results and their applicability in clinical practice and research of otitis media.

OBJECTIVE

To review existing literature on health-related quality of life research in children with otitis media with respect to: (1) the measured impact of otitis media on HRQoL; and (2) the applicability of HRQoL instruments used in research and clinical practice based on their characteristics and contents.

METHODS

A search was performed in EMBASE (1988-November 2004) and on NLM Gateway (1966-November 2004) for studies assessing health-related quality of life or functional health status by means of disease-specific or generic questionnaires in children aged 0-18 years with chronic or recurrent otitis media with effusion or acute otitis media. The bibliographies of the selected articles were searched manually.

RESULTS

Only 13 of the 141 retrieved articles retrieved fulfilled the criteria for inclusion. In these studies, physical suffering (pain, high fever, etc.), difficulties with hearing or speech, behavioural problems, or emotional distress were reported to be the most important problems experienced by children with otitis media. Almost all instruments applied in these studies measure functional health status instead of health-related quality of life. Data on validity and reliability of these instruments are incomplete.

CONCLUSIONS

Recurrent or chronic otitis media is reported to have a substantial and negative effect on various domains of functional health status and health-related quality of life of children. The OM-6 appears to be the best available instrument to assess functional health status in children with OM in a research setting. However, the lack of true HRQoL instruments as well as incomplete data on their reliability and validity, limit both our current knowledge of HRQoL in OM and the application of current instruments in both research and clinical practice.