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Study on the concentrations of cerebrospinal fluid immunoglobulin G and albumin in children
K L Hung1, M T Chang, M L Tsai
1Department of Pediatrics, Cathay General Hospital, Taipei, Taiwan, R.O.C.
Insights
This study establishes reference values for immunoglobulin G (IgG) and albumin in children, revealing how blood-brain barrier (BBB) function matures postnatally. The IgG index remains stable, indicating its utility in assessing central nervous system inflammation.
Area of Science:
- Pediatric Neurology
- Neuroimmunology
- Biochemistry
Background:
- The blood-brain barrier (BBB) regulates the passage of substances between the blood and cerebrospinal fluid (CSF).
- Establishing age-specific reference values for proteins like immunoglobulin G (IgG) and albumin is crucial for evaluating BBB function in children.
- Understanding BBB maturation is key to diagnosing neurological conditions in pediatric populations.
Purpose of the Study:
- To determine reference values for CSF/serum IgG and albumin concentrations in healthy Chinese children aged 0-15 years.
- To assess the age-dependent changes in BBB permeability during early childhood.
- To evaluate the stability and diagnostic potential of the IgG index for central nervous system inflammation.
Main Methods:
- Measurement of immunoglobulin G (IgG) and albumin concentrations in CSF and serum samples from 118 healthy children.
- Calculation of CSF/serum IgG ratio, CSF/serum albumin ratio, and IgG index for each participant.
- Statistical analysis to determine age-related trends and reference ranges.
Main Results:
- CSF IgG and CSF/serum IgG ratio decreased significantly in the first six months, suggesting a postnatal impediment to IgG diffusion across the BBB.
- CSF/serum albumin ratio declined until one year of age, indicating a maturational process of the BBB with preferential passage of smaller proteins.
- The IgG index demonstrated no age-dependent variation, remaining constant in healthy children, suggesting its reliability as an indicator of CNS inflammation.
Conclusions:
- The study provides essential reference ranges for IgG and albumin in pediatric CSF and serum, aiding in BBB function assessment.
- BBB permeability undergoes significant maturation in the first year of life, characterized by differential protein handling.
- The age-independent IgG index is a robust marker for detecting central nervous system inflammation, irrespective of age in childhood.
Abstract:
Concentrations of immunoglobulin G (IgG) and albumin in cerebrospinal fluid (CSF) and serum were measured in 118 "normal" Chinese children from birth to 15 years old to obtain the reference values for the evaluation of the blood-brain barrier (BBB) function. The values of the CSF/serum IgG ratio, CSF/serum albumin ratio and IgG index (IgG ratio/albumin ratio) were then calculated for each subject. A relation was found between the content of IgG in CSF and serum depending on age. The gradual decrease of CSF IgG and IgG ratio during the first 6 months indicated a postnatal impediment of the diffusion of IgG from the blood to the CSF. In the meanwhile the CSF/serum albumin ratio continued to drop until the age of one year. The slower slope of the decrement of the latter ratio further demonstrated the differential permeability of the BBB in favor of the shift of small molecular protein. The change of the protein permeability within the first year of life shows a characteristic of the maturational process of the BBB. Nevertheless, IgG index has no age-dependent variation throughout the childhood period. It remains constant in the absence of inflammation within the central nervous system.