Acceleration of B16 melanoma growth in mice after blood transfusion.

Evidence suggests that blood transfusions depress immunologic reactivity; as some tumors are influenced by the immune status of their host, it is possible that transfusions could promote tumor growth by impairing host immunity. The influence of blood transfusion on the growth of a transplantable B16 melanoma was examined in nude (athymic) CBA mice and immunocompetent C57 BL/6J mice. Recipients were given infusions of saline solution or syngeneic or H-2-incompatible allogeneic blood transfusions on two occasions 3 days apart. Infusions were begun 10 days before inoculation of a single cell suspension of B16 melanoma. Growth was determined by measurements of primary tumor volume and tumor weight after excision. There was no statistically significant difference in tumor size or weight between the three recipient groups of athymic mice. However, immunocompetent mice given H-2-incompatible allogeneic blood had higher rates of tumor engraftment--saline solution recipients versus allogeneic recipients: chi 2 = 13.2, df = 1, p less than 0.001; syngeneic recipients versus allogeneic recipients: chi 2 = 2.97, df = 1, p greater than 0.05. In the allogeneic group significantly larger and heavier tumors developed than in mice given syngeneic blood or saline solution. The study indicates that H-2-incompatible allogeneic blood transfusions can influence the growth of a transplantable murine tumor by a mechanism that involves a cell-mediated immune response.