Cytotoxic antibody responses in astrocytoma patients. An improved allogeneic assay.

Early diagnosis of brain tumors may be facilitated by a microcytotoxicity assay which the authors have used to detect a humoral immune response against an allogeneic glioblastoma cell line. Sixty-seven of 82 serum samples (82%) from astrocytoma patients elicited significant cytotoxicity, while only six of 65 samples (9%) from normal blood-bank donors demonstrated a similar response. Positive results were more frequently obtained in lower-grade astrocytomas. Meningiomas, acoustic schwannomas, pituitary adenomas, and metastatic tumors were positive in variable numbers of cases. A small series of serum samples were platelet-absorbed to insure that cytotoxicity was not merely due to histocompatibility antigens, and seven of eight samples, when retested on the target cell line, remained significantly positive. The assays were performed under strictly monitored conditions that afforded optimum reliability and minimal experimental variability. As the specificity of this test increases, it may lead to early detection of astrocytomas.