[Microglia--biology and relevance to disease].

Microglia, the resting macrophage population in the brain and spinal cord, has a central role in inflammatory processes and in acute and chronic degenerative diseases of the central nervous system. The possibility of utilizing microglia diagnostically has emerged with the prospect of visualization of reactive microgliosis via positron emission tomography. Microglia might also have a therapeutic potential by way of recruitment of microglial precursors from the blood with the opportunity to introduce genetically modified cells lesion-specifically into the central nervous system via the bloodstream. Knowledge about microglial function has preferentially been obtained via studies in experimental animal models of the pathological central nervous system. In spite of the rather extensive knowledge regarding the pathophysiological implications of these cells, their function in the normal central nervous system remains rather unknown.