Granulocyte Reserve Following Radiation Therapy as Studied by the Response to a Bacterial Endotoxin

The granulocyte response to an intravenous injection of Pyrexal, a highly purified bacterial endotoxin was used as an assay of the marrow granulocyte reserve in patients who had received radiation therapy for various types of neoplasms. The response to the endotoxin was correlated with the amount of marrow irradiated. Only those patients with large volumes of marrow irradiated had abnormal responses to Pyrexal. No patient receiving radiation therapy to the head and neck, or thorax, or pelvis alone, regardless of dose, developed an abnormal response to Pyrexal. Early changes in the marrow granulocyte reserve were also studied in patients before, during and after radiation therapy.