Two-color analysis of peripheral blood lymphocytes in patients with malignant tumour after low dose half (or total) body irradiation

The mechanism of anti-tumour effect of low dose total body irradiation applied for non-Hodgkin's lymphoma is still unknown. Two-color analyses of peripheral blood lymphocytes from ten patients with non-Hodgkin's lymphoma or advanced cancer who received low dose total body irradiation (TBI) or half body irradiation (HBI), were performed to be a help to reveal the mechanism. The results of these analyses indicated that the proportion of helper T lymphocytes, helper-inducer T lymphocyts and cytotoxic T lymphocytes increased during TBI or HBI. On the other hand, the proportion of suppressor-inducer T lymphocytes and suppressor T lymphocytes seemed to decrease slightly. The extent of bone marrow suppression of twice-a-week TBI or HBI was clinically no problem, but in the case of thrice-a-week TBI, prolonged bone marrow suppression might occur. In the case of half body irradiated five patients who were administered with lentinan for several weeks to several months before TBI or HBI, the pre-HBI value of the proportion of cytotoxic T lymphocyte fraction was found to be high, and the increment of the proportion of helper T lymphocyte was larger than that of non-lentinan-treated cases. (author)