Plasma IgG, IgG subclasses and acute-phase proteins in children with recurrent acute otitis media

Primrose syndrome associated with unclassified immunodeficiency and a novel ZBTB20 mutation

Primrose syndrome is a congenital malformation syndrome characterized by intellectual disability, developmental delay, progressive muscle wasting, and ear lobe calcification. Mutations in the ZBTB20 gene have been established as being accountable for this syndrome. In this study, a novel de novo ZBTB20 mutation, NM_001164342.2:c.1945C>T (p.Leu649Phe), has been identified through whole exome sequencing (WES) in a female patient presenting a typical Primrose phenotype. Because the present patient exhibited recurrent otitis media, detailed immunological examinations were performed in this study and subnormal immunoglobulin levels were firstly identified in a Primrose patient. Anatomical anomaly of the inner ear has never been reported in this patient and WES data did not include any relevant variants causally linked with the immunologic defect. Thus, there is a possibility of a relation between an unclassified immunodeficiency with selective IgG2 deficiency and Primrose syndrome and this may be the reason of recurrent otitis media frequently observed in Primrose patients. Because subnormal levels of IgG2 in this patient might be caused by an unrelated and still uncharacterized genetic cause, further studies are required to prove the causal link between aberrant ZBTB20 function and immunodeficiency.

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.

Normalized immunoglobulin patterns in adults with recurrent acute otitis media and low IgG2 levels during early childhood

OBJECTIVES

Children who suffer from recurrent acute otitis media (rAOM) sometimes display low immunoglobulin levels. It is not known whether the differences in immunoglobulin levels remain during adulthood or if rAOM-patients have more episodes of AOM and airway infections as adults.

METHODS

A study on adults, with a history of rAOM during childhood, was performed. The immunologic status and individual disposition for upper airway infections were evaluated in 28 subjects who originally participated in a study on rAOM between 1979 and 1983. 13 subjects had suffered from rAOM during early childhood and 15 subjects without rAOM served as a control group. The study included analysis of immunoglobulins in serum and self evaluation regarding susceptibility to infections of the upper airway.

RESULTS

There was no difference between the groups neither regarding IgG2 concentrations nor specific antibody levels. No episodes of AOM were reported after 20 years of age in any of the study subjects. The history of airway infections was similar in both groups.

CONCLUSIONS

Study subjects who had rAOM combined with low IgG2 levels during childhood had a normalized immunoglobulin pattern as adults.

High pneumococcal serotype specific IgG, IgG1 and IgG2 levels in serum and the middle ear of children with recurrent acute otitis media receiving ventilation tubes

Recurrent acute otitis media (AOM), frequently caused by Streptococcus pneumoniae, is a major paediatric health problem. A reduced antibody response against pneumococcal polysaccharides may contribute to an increased susceptibility to AOM. Using a multiplex bead-based assay we measured IgG, IgG1 and IgG2 levels against 11 pneumococcal polysaccharides in serum samples from 166 children below 3 years of age with a history of at least 3 episodes of acute otitis media receiving ventilation tubes, and 61 healthy controls. Pneumococcal serotype specific IgG was also determined in 144 middle ear effusion samples. Pneumococcal serotype specific IgG, IgG1 and IgG2 levels were similar in children with or without AOM, except for IgG and IgG1 levels against serotype 5, which were significantly higher in children with a history of frequent AOM (IgG: 137.5 μg/ml vs. 84.0 μg/ml; p=0.02; IgG1: 24.5 μg/ml vs. 18.2 μg/ml; p=0.05). The age-related development of pneumococcal serotype-specific IgG, IgG1 and IgG2 levels was similar in children with or without a history of AOM. Pneumococcal serotype specific IgG was present in middle ear effusion and these levels correlated significantly with serum titres. Children with a history of frequent AOM receiving ventilation tubes do not have a deficient IgG, IgG1 or IgG2 response against pneumococcal polysaccharides, either induced by vaccination or due to natural exposure. The strong correlation between IgG levels in serum and the middle ear suggests parenteral pneumococcal conjugate vaccination induces antibodies in the middle ear which may therefore contribute to reducing the burden of AOM.

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.

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.

Deficient IgA and IgG2 anti-pneumococcal antibody levels and response to vaccination in otitis prone children

OBJECTIVE

To evaluate the isotype and IgG subclass distribution of anti-pneumococcal antibodies and response to polysaccharide vaccination in otitis prone children.

METHODS

IgG1, IgG2 and IgA antibodies to pneumococcal serotypes 3, 4, 6B, 9V, 14, 19F and 23F were determined in otitis prone children and in an age-matched healthy control population. Patients were immunized with a 23-valent pneumococcal polysaccharide vaccine. The antibody response was measured 4 weeks later.

RESULTS

Geometric mean IgA and IgG2 antibody levels for all seven pneumococcal serotypes tested were significantly lower in otitis prone children than in the control population. After immunization, there was no significant increase in geometric mean IgG2 anti-serotype 6B, 19F and 23F pneumococcal polysaccharide (weak immunogenic), but also no increase for IgG2 anti-serotype 4 and 14. Post immunization IgG2 antibody titers for serotypes 6B, 9V and 19F even remained below titers of non-vaccinated controls. Nine out of 29 otitis prone children were colonized nasopharyngeally with Streptococcus pneumoniae during the time of vaccination; these children had an even more severely impaired systemic antibody response.

CONCLUSIONS

Otitis prone children, while having normal IgG1 antibody levels, have low IgG2 and IgA anti-polysaccharide antibody levels and fail to respond in these subclasses upon vaccination with pneumococcal polysaccharide vaccine.

Mucosal Immunity and Bacteriology of the Eustachian Tube

The pathogenesis of otitis media is a multifaceted process that is not completely understood. Eustachian tube dysfunction plays a central but uncertain role, as do viral and bacterial microorganisms. Of the latter, the three most important are Streptococcus pneumoniae, Haemophilus influenzae and Moraxella catarrhalis. This article reviews the various mechanisms of infection and the immune system's response to them.

Spontaneous immunoglobulin production by adenoidal and tonsillar lymphocytes in relation to age and otitis media with effusion

Spontaneous immunoglobulin (Ig) production by autologous adenoidal and tonsillar lymphocytes cultured without any mitogen was measured by an enzyme-linked immunosorbent assay (ELISA) in 18 children with or without otitis media with effusion (OME). Both IgG and IgA levels synthesized by adenoidal or tonsillar lymphocytes significantly increased with age. The average concentrations of IgG and IgA produced by adenoidal lymphocytes from children with OME were significantly lower than those from children without OME. Adenoidal lymphocytes produced IgG and IgM at significantly lower levels than autologous tonsillar lymphocytes did in children with OME. In contrast, no significant difference between adenoidal and tonsillar lymphocytes was seen on Ig production for any isotypes in children without OME. These results may indicate immunological impairment of the adenoids associated with OME.

Mannan-binding protein--levels in plasma and upper-airways secretions and frequency of genotypes in children with recurrence of otitis media

We have investigated a possible association between recurrence of otitis media and low concentrations of mannan-binding protein (MBP) in plasma and upper-airway secretions. The protein concentration was measured in plasma (n = 76), nasopharyngeal secretions (n = 83) and middle ear effusions (n = 73) from otitis-prone children, children with less recurrence of acute otitis media, children with no previous history of acute otitis media, but suffering from secretory otitis media, and healthy children. Moreover, genetic polymorphisms associated with low MBP plasma levels were investigated in DNA from nasopharyngeal tonsils of 89 children with recurrence of otitis media. A wide range of MBP plasma concentrations was found. No statistically significant differences in MBP plasma concentration were observed between patients and controls. Nor was there any increased frequency of the genotypes associated with low MBP plasma concentrations. Thus, our results do not support the assumption that low concentration and/or MBP deficiency alone predispose to recurrence of otitis media in Caucasian children. MBP was detected in both nasopharyngeal secretions (1/175 of plasma level) and middle ear effusions (1/4 of plasma level), suggesting a role for the protein in the local mucosal immune defense system at these locations. In contrast, MBP was undetectable in 53 samples of mixed-saliva.