Are microglial and astroglial activation the result of residual damage or ongoing damage to the brain?
It remains unclear how and when microglia and astroglia become activated in the brain of autistic patients. Neuroglial responses in autism may be part of primary (intrinsic) reactions that result from disturbances in neuroglial function or neuronal-neuroglial interactions during brain development. They may also be secondary (extrinsic), resulting from unknown factors that disturb prenatal or postnatal CNS development (e.g. infections, toxins, etc). Both astrocytes and microglia are critical for brain development. MHC class II (HLA-DR antigen)-positive microglia colonize the developing CNS during the second trimester of pregnancy. It is possible that the presence of activated microglia in the brain in autism may reflect abnormal persistence of fetal patterns of development. This may be in response to genetic or environmental (e.g. intrauterine, maternal) factors. Our study of brains of autistic patients showed that regardless of age, history of epilepsy, developmental regression or ment
