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Published on: January 26, 2019
Specific antibody deficiency with normal immunoglobulin concentration in children with recurrent respiratory
A Quezada1, X Norambuena2, J Inostroza3
1Department of Pediatrics, School of Medicine, University of Chile, Santiago de Chile, Chile.
Insights
Evaluating immunological competence in children with recurrent respiratory infections (RRI) is crucial. A polysaccharide antigen response test helps detect specific antibody deficiency (SAD) by assessing antibody levels over time.
Area of Science:
- Pediatric Immunology
- Infectious Diseases
- Allergy and Immunology
Background:
- Recurrent respiratory infections (RRI) in children without other immune abnormalities warrant investigation for specific antibody deficiency (SAD).
- Assessing immunological competence is key in diagnosing the cause of unexplained RRI.
- Polysaccharide antigen response testing serves as a valuable tool in this diagnostic process.
Purpose of the Study:
- To prospectively evaluate the immunological competence of children with RRI using polysaccharide antigen response.
- To detect specific antibody deficiency (SAD) in children experiencing recurrent respiratory infections.
- To assess the persistence of specific antibody responses post-vaccination.
Main Methods:
- 20 children (3-14 years) with RRI were immunized with a 23-valent polysaccharide anti-pneumococcal vaccine.
- Anti-polysaccharide IgG antibody levels for 10 pneumococcal serotypes were measured using ELISA at baseline, 45 days, and one year post-immunization.
- Normal response criteria were age-dependent, based on antibody levels and percentage of serotypes responding.
Main Results:
- 19 out of 20 children showed a normal initial response to the vaccine.
- At one year, 8 out of 20 children exhibited deficient antibody responses, suggesting impaired antibody persistence.
- A significant association was observed between deficient responses and the presence of asthma and allergic rhinitis.
Conclusions:
- The study proposes a stepwise approach for diagnosing SAD, starting with ruling out other causes, followed by immunoglobulin level assessment.
- Measuring the response to polysaccharide pneumococcal antigens is a recommended final step for SAD detection.
- Impaired persistence of specific antibodies may be a key factor in children with RRI, asthma, and allergic rhinitis.
Background:
Response to polysaccharide antigens is a test to evaluate the immunological competence of children with recurrent respiratory infections (RRI) of unknown cause and no other immune system abnormality. In order to detect specific antibody deficiency (SAD), a group of children with RRI without other immunodeficiency were prospectively studied.
Methods:
We included 20 children (12 male), age range 3-14 years, with six or more annual episodes of respiratory infections (RI); one or more monthly episodes of RI during the winter months; or three or more annual episodes of lower RI. The children were immunised with 23-valent polysaccharide anti-pneumococcal vaccine, and ELISA was used to measure anti-polysaccharide IgG antibody levels for 10 pneumococcal serotypes at baseline (T0), and 45 days (T1) and one year post-immunisation (T2). Post-immunisation response above 1.3 μg/ml for more than 50% of the serotypes was considered normal for children 2-5 years, and for more than 70% of the serotypes in children older than 5 years.
Results:
At T1 19/20 children showed a normal response for their age, and only one patient showed a deficient response, suggestive of classic moderate SAD. At T2, 8/20 patients showed deficient responses, suggestive of impaired persistence of specific antibodies. There was a noteworthy association between deficient response and asthma and allergic rhinitis.
Conclusions:
We propose first ruling out local or systemic causes, then performing serum immunoglobulin IgM, IgG, IgA, IgE and IgG subclass levels, and finally measuring response to polysaccharide pneumococcal antigens for detection of SAD.
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