LOCALIZATION OF T-CELL RECEPTOR (TCR)-GAMMA-DELTA(-CELLS INTO HUMAN COLORECTAL-CANCER - FLOW CYTOMETRIC ANALYSIS OF TCR-GAMMA-DELTA EXPRESSION IN TUMOR-INFILTRATING LYMPHOCYTES() T)

We analysed TCR-gamma delta expression in tumour-infiltrating lymphocy tes (TIL) obtained from 13 patients with colorectal cancer and simulta neously isolated the T lymphocytes from normal intestinal tissue (IL) to compare the frequencies of TCR-gamma delta expression in TIL, IL, a nd peripheral blood lymphocytes (PBL) in the same patient. Flow cytome tric analysis showed that the frequency of TCR-gamma delta expression in TIL (2.75 +/- 1.84%) was significantly lower than that in IL (15.28 +/- 9.45%, P < 0.01). However, a larger quantity of TIL was separated than IL per unit weight of specimen, so the total number of gamma del ta T cells obtained per unit weight was not different between tumour t issue and normal intestine. In addition, phenotypic analysis revealed that about half of the TCR-gamma delta(+) TIL were CD8(+) (CD4(+), 3.0 +/- 3.1%; CD8(+), 54.7 +/- 19.9%, mean +/- s.d. of five patients), an d a very similar result was obtained in TCR-gamma delta(+) IL(CD4(+), 2.7 +/- 2.4%; CD8(+), 53.1 +/- 17.4%). In contrast, most TCR-gamma del ta(+) PBL were double-negative (CD4(+), 3.2 +/- 3.0%; CD8(+), 20.6 +/- 7.4%). These results indicated that TCR-gamma delta(+) CD8(+) T cells selectively and consistently localized in colorectal tumour tissue, s imilarly to normal intestinal epithelium.