Immunological deficiency in "otitis-prone" children

Peripheral blood immunological parameters of children with adenoid hypertrophy with otitis media with effusion: propensity score matching

PURPOSE

To evaluate peripheral blood immunological parameters and the possible correlation with age, gender and adenoid size in children with adenoid hypertrophy with OME.

METHODS

A total of 664 children with adenoid hypertrophy were initially enrolled in our study, of which 83 had concomitant OME. To minimize selection bias, we performed one to two propensity score matching (PSM) between children with and without OME. After PSM, 80 children with OME (OME group) and 157 children without OME (adenoid hypertrophy [AH] group) were selected. The patients' peripheral blood samples were prepared prior to surgery and their immunological parameters were compared between groups.

RESULTS

Compared to the AH group, the serum level of C3 was significantly higher in the OME group (0.88 ± 0.01 g/L vs. 0.94 ± 0.02 g/L; p = 0.014), which was the only independent risk factor for OME (odds ratio 13.58, 95% confidence interval 1.25-147.99; p = 0.032). However, no such difference was seen for serum immunoglobulin (IgG, IgA, IgM, IgE), T cell subsets (CD3+, CD4+ and CD8+ T cells), or lymphocytes and monocytes. Further subgroup analyses showed that in children ≤ 5 years old, the C3 level was significantly higher in OME patients (p = 0.023). A subgroup analysis based on sex indicated that there was a significantly higher level of serum C3 (p = 0.009) and lower CD3+ and CD4+ T cells (p = 0.010 and p = 0.021, respectively) in girls with OME compared to those without OME. No association between immunological parameters and adenoid size was found.

CONCLUSIONS

There were no significant differences in cellular immunology and humoral immune indicators in children with adenoid hypertrophy with or without OME. In children ≤ 5 years old, significantly higher serum C3 levels in patients with OME demonstrate excessively activated C3 in comparison to patients without OME. For girls, a higher serum level of C3 with a lower amount of CD3+ and CD4+ T cells may be associated with OME.

Probiotics for preventing acute upper respiratory tract infections

BACKGROUND

Probiotics may improve a person's health by regulating their immune function. Some trials have shown that probiotic strains can prevent respiratory infections. Even though the previous version of our review showed benefits of probiotics for acute upper respiratory tract infections (URTIs), several new studies have been published.

OBJECTIVES

To assess the effectiveness and safety of probiotics (any specified strain or dose), compared with placebo, in the prevention of acute URTIs in people of all ages, at risk of acute URTIs.

SEARCH METHODS

We searched CENTRAL (2014, Issue 6), MEDLINE (1950 to July week 3, 2014), EMBASE (1974 to July 2014), Web of Science (1900 to July 2014), the Chinese Biomedical Literature Database, which includes the China Biological Medicine Database (from 1978 to July 2014), the Chinese Medicine Popular Science Literature Database (from 2000 to July 2014) and the Masters Degree Dissertation of Beijing Union Medical College Database (from 1981 to July 2014). We also searched the World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP) and ClinicalTrials.gov for completed and ongoing trials on 31 July 2014.

SELECTION CRITERIA

Randomised controlled trials (RCTs) comparing probiotics with placebo to prevent acute URTIs.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed the eligibility and quality of trials, and extracted data using the standard methodological procedures expected by The Cochrane Collaboration.

MAIN RESULTS

We included 13 RCTs, although we could only extract data to meta-analyse 12 trials, which involved 3720 participants including children, adults (aged around 40 years) and older people. We found that probiotics were better than placebo when measuring the number of participants experiencing episodes of acute URTI (at least one episode: odds ratio (OR) 0.53; 95% confidence interval (CI) 0.37 to 0.76, P value < 0.001, low quality evidence; at least three episodes: OR 0.53; 95% CI 0.36 to 0.80, P value = 0.002, low quality evidence); the mean duration of an episode of acute URTI (mean difference (MD) -1.89; 95% CI -2.03 to -1.75, P value < 0.001, low quality evidence); reduced antibiotic prescription rates for acute URTIs (OR 0.65; 95% CI 0.45 to 0.94, moderate quality evidence) and cold-related school absence (OR 0.10; 95% CI 0.02 to 0.47, very low quality evidence). Probiotics and placebo were similar when measuring the rate ratio of episodes of acute URTI (rate ratio 0.83; 95% CI 0.66 to 1.05, P value = 0.12, very low quality evidence) and adverse events (OR 0.88; 95% CI 0.65 to 1.19, P value = 0.40, low quality evidence). Side effects of probiotics were minor and gastrointestinal symptoms were the most common. We found that some subgroups had a high level of heterogeneity when we conducted pooled analyses and the evidence level was low or very low quality.

AUTHORS' CONCLUSIONS

Probiotics were better than placebo in reducing the number of participants experiencing episodes of acute URTI, the mean duration of an episode of acute URTI, antibiotic use and cold-related school absence. This indicates that probiotics may be more beneficial than placebo for preventing acute URTIs. However, the quality of the evidence was low or very low.

Otitis media: viruses, bacteria, biofilms and vaccines

Otitis media typically presents as either acute otitis media (AOM), with symptoms including fever, otalgia, otorrhoea or irritability and short duration; or as otitis media with effusion (OME), which is often asymptomatic and characterised by accumulation of fluid in the middle ear.

Diagnostic certainty of otitis media is challenging, given the young age of patients and variability of symptoms.

Otitis media predominantly occurs as coincident to viral upper respiratory tract infections and/or bacterial infections.

Common viruses that cause upper respiratory tract infection are frequently associated with AOM and new‐onset OME. These include respiratory syncytial virus, rhinovirus, adenovirus, parainfluenza and coronavirus.

Predominant bacteria that cause otitis media are Streptococcus pneumoniae, Moraxella catarrhalis, and non‐typeable Haemophilus influenzae.

Antibiotic therapy does not significantly benefit most patients with AOM, but long‐term prophylactic antibiotic therapy can reduce the risk of otitis media recurrence among children at high risk.

In Australia, 84% of AOM is treated with antibiotic therapy, which contributes to development of antibiotic resistance.

Vaccine development is a key future direction for reducing the world burden of otitis media, but requires polymicrobial formulation and ongoing monitoring and modification to ensure sustained reduction in disease burden.

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.

Antibody levels after regular childhood vaccinations in the immunological screening of children with recurrent otitis media

Recurrent otitis media may be related to defects in specific antibody production, as suggested previously. This might be reflected in lower antibody responses to vaccinations administered in the context of the national childhood vaccination program in children suffering from recurrent otitis media. In a cross-sectional study we determined the levels of antidiphtheria, antitetanus, anti- Haemophilus influenzae type b (anti-Hib) and antimeasles antibodies in sera of 163 children with two or more episodes of acute otitis media per year and in 143 children with repeated periods of persistent otitis media with effusion each lasting at least 3 months. The control group consisted of 521 age-matched healthy children, who were free of recurrent respiratory tract infections. Children with recurrent acute otitis media, including highly otitis-prone children, showed higher antidiphtheria and antitetanus antibody titers compared to controls. No differences were observed in anti-Hib and antimeasles antibody levels between children with recurrent acute otitis media and controls, nor did any of the antibody levels in children with persistent otitis media with effusion differ from those in controls. Therefore, the results of our study do not point toward a generalized immunological hyporesponsiveness in children with recurrent acute otitis media and persistent otitis media with effusion. Determination of antibody responses to regular vaccines is not indicative for otitis-proneness.

Immunoglobulins in otitis-prone children

Defective or immature antibody responses to pathogens in children may explain the increased susceptibility to acute otitis media (AOM) in otitis-prone children. In literature, data on immunology have been based on studies of small groups of severely otitis-prone children and have not been consistent. Humoral immune status was assessed in 365 children, 1-7 years old, with two or more documented episodes of AOM in the previous year. Children with 4 or more episodes in the preceding year were defined as otitis-prone. Serum immunoglobulin levels were determined by radial immunodiffusion. Immunoglobulin levels of otitis-prone children were compared with those of children who had experienced 2-3 AOM episodes per year. Children with recurrent episodes of AOM were found to have normal or increased serum IgA, IgM, IgG, and IgG1 levels compared with normal values for age, whereas the serum IgG2 levels were mostly in the lower normal range. Twenty-two percent of all children showed IgG2 levels lower than 2 SD below the age-specific mean. Interestingly, the otitis-prone group of children showed significantly lower median and mean levels for all immunoglobulins compared with those children with only 2-3 previous AOM episodes. Lower immunoglobulin levels in otitis-prone children suggest a generalized decreased antibody response in otitis-prone children.

Classification of otitis media and surgical principles

Otitis media is an important disease of children and adults and is caused by multiple interrelated factors, including infection, eustachian tube dysfunction, allergy, and barotrauma. This article includes a pertinent review of the literature regarding otitis media. The pathogenesis, classification, and treatment of otitis media in children and adults are also reviewed in this article. Additionally, therapy is discussed with emphasis on the surgical options appropriate at each stage.