Central nervous system inflammation across the age span

This article reviews the influence of age on the development and course of central nervous system (CNS) inflammatory diseases and relates these to genetic and epidemiologic factors and to the age-related properties of both the immune and nervous systems and their interactions.

There is increased recognition of the onset of multiple sclerosis, the prototype CNS inflammatory/demyelinating disease, outside the expected peak age in young adults. Study of childhood-onset MS cases with comparison to those with uniphasic acquired inflammatory demyelinating syndromes, has helped to better define the clinical spectrum of both types of disorders and provides opportunities to define mechanisms linking recognized genetic and environmental risk factors and disease. Studies of late-onset cases implicate the enhanced role of innate immune mechanisms and immune responses compartmentalized within the CNS in driving a more progressive disease course. The influence of age on incidence and course of multiple sclerosis is compared with the wider spectrum of CNS inflammatory disorders with identified pathogenic mechanisms.

Intrinsic properties of the immune and nervous systems, coupled with the impacts on these systems by environmental factors and by the consequences of CNS tissue injury, underlie the age-related differences in incidence and course of inflammatory/demyelinating disorders of the CNS.