Macrophages, lymphocytes and major histocompatibility complex (HLA) class II antigens in adult human sensory and sympathetic ganglia.

We report an immunocytochemical study of sensory and autonomic ganglia from ten adult human subjects aged 18-83 years without peripheral nerve disease using monoclonal antibodies to macrophages, lymphocytes and human leukocyte (HLA) class II antigens. All ganglia and their associated nerve roots were found to contain a population of resident macrophages which accounted for 5-20% of the cells present. These macrophages and, in addition, many Schwann cells and satellite cells, gave reactions for HLA class II antigens in all cases. Very low numbers of CD3 and CD8 lymphocytes were also regularly detectable in sensory and autonomic ganglia. The resident macrophages may have important immunological and trophic functions. Their possible role in the development of immune-mediated peripheral nerve disease deserves further study.