Our study clearly demonstrates that depressive mood is the main factor influencing QOL. The disability status, fatigue and reduced sleep quality have an impact mainly on physical domains of life quality.

This report defines the bone marrow-derived elements found in the central nervous system of adult rat radiation chimeras. Four cell types were identified which bore the major histocompatibility (MHC) class I molecules of the donor rat strain thereby indicating a marrow origin. They were: meningeal macrophages, perivascular "microglial" cells, lymphocytes and rare cells with parenchymal microglial morphology. These cells were examined by immunohistochemical methods at the light microscopic and ultrastructural levels. Extended descriptions of the perivascular marrow-derived elements and the parenchymal microglial cells are presented. These latter two cell types, which exist in humans, have a significant role in neuroimmune processes and most probably function as the antigen-presenting cells in the central nervous system of mammals.

No abstract

Infection of the central nervous (CNS) system by the human immunodeficiency virus (HIV) depends on the migration of infected hematogenous cells into the brain. We thus used quantitative light and electron microscopic immunocytochemistry to study the homing and turnover of bone marrow derived cells in the CNS in radiation bone marrow chimeras under normal conditions and in experimental autoimmune encephalomyelitis (EAE) as an experimental model of brain inflammation. Our studies suggest the following conclusions. First, the central nervous system is continuously patrolled by a small number of T-lymphocytes and monocytes. Meningeal and perivascular monocytes are slowly replaced by hematogenous cells under normal conditions, and this turnover is accelerated in the course of inflammation. In contrast, resident microglia represent a very stable cell pool, which in adult animals is only exceptionally replaced by hematogenous cells, even after recovery from severe brain inflammation. Second, although in bone-marrow-chimeric animals resident microglia, astrocytes, and ependymal cells are not able to present antigen to Lewis T-lymphocytes, the inflammatory reaction in EAE is qualitatively and quantitatively similar in these animals compared to fully histocompatible Lewis rats. Finally, resident microglia express the macrophage activation antigen ED1. Thus, microglia cells appear to function as effector cells in EAE lesions.