Changes in lymphoid cell distribution after intraperitoneal administration of 32P colloids

The effect of intraperitoneal administration of 32P colloids on the distribution of T lymphocyte subpopulations and monocytes was studied using monoclonal antibodies and a flow cytometry technique. Thirty-nine patients with ovarian carcinoma without residual tumor after primary operation were examined either before the administration of 260 to 370 MBq of 32P, 4 to 6 days after therapy, or 4 to 10 months after therapy. A significant reduction of circulating OKT4+ (T helper) cells occurred after therapy, and the reduction lasted throughout the observation period. Monocyte numbers were not significantly changed. It is concluded that intraperitoneal instillation of the 32P isotope may induce the same type of changes in circulating lymphoid cells as those seen after external field irradiation.