[Localization of immunoglobulins in the central nervous system].

The affinity of IgG to the central nervous system has been demonstrated by several authorities. The present study revealed the physiological localization of immunoglobulins. Developing human brains were obtained from autopsies, and the regional localization of IgG, IgA and IgM was examined as a function of age. Thirteen brains from children, aged 3 months to 13 years, were evaluated for IgG localization. Four other cases, aged 3 to 7 months, were stained for IgG subclasses, IgA and IgM. Positive IgG staining was observed in neurons and glial cells of the cerebrum and Purkinje cells of the cerebellum in 5 cases, aged 3 to 7 months. It was decreased in 4 cases aged 1 year (3/4 in the nerve cells of the hippocampus and Purkinje cells, 2/4 in those of the amygdala and parietal cortex, and 1/4 in other regions). IgG was absent except in the Purkinje cells of four cases, aged 3 to 13 years. Every IgG subclass and IgA existed in neurons and glial cells of the cerebrum and Purkinje cells of the cerebellum in all cases. IgM staining, however, was negative in the nerve cells of the cerebral cortex although it was positive in Purkinje cells of the cerebellum and basal ganglia. These findings suggest that the immunoglobulins possibly passed through the premature blood-brain barrier in infants, were taken up by the nerve and glial cells in the cerebral cortex and other deep structures of the central nervous system, and may exert some effects on the developing process of the brain.