S-100 beta positive human T lymphocytes: Their characteristics and behavior under normal and pathologic conditions

The characteristics of human S-100 beta-positive T lymphocytes (S-100 beta⁺ T cells) and their fluctuation in peripheral blood under normal and various pathologic conditions were investigated. S-100 beta⁺ T cells were small lymphocytes with no particular subcellular structures and showed a proliferative response to mitogens. They were present mainly in peripheral blood under normal conditions but accumulated in T zones of lymph nodes with nonspecific T-zone hyperplasia, where numerous interdigitating reticulum cells existed. In healthy adults approximately 1% to 4% (mean 3.4%) of peripheral blood mononuclear cells were S-100 beta⁺ T cells. The proportion of S-100 beta⁺ T cells in peripheral blood tended to significantly decrease (<0.5%) in patients with neoplastic diseases; this tendency was apparently related to tumor progression.