Expression of lymphocyte, macrophage and class I and II major histocompatibility complex antigens in normal human dorsal root ganglia.

We analyzed the expression of lymphocyte, macrophage and class I and II (HLA-DR) major histocompatibility complex (MHC) antigens in normal dorsal root ganglia (DRG) from 19 patients without neurological disease by using an avidin-biotin immunoperoxidase technique. Satellite cells expressed class I and II MHC antigens. The intensity of HLA-DR staining varied among the DRG and was not related to age, history of cancer or infection, or number of T lymphocytes in the DRG. Monoclonal antibodies EBM11 and Leu-M3, that recognize cells of monocyte/macrophage lineage, stained a population of cells in all DRG. Positive cells had an elongated shape and were in the interstitial tissue between the satellite cells. These findings may be relevant to the understanding of the immune mechanisms involved in the neuronal damage of sensory neuropathies of presumably autoimmune origin such as those associated with small-cell lung cancer or Sjögren's syndrome.