Detection of Anti-tumour Cell Mediated Immunity and Serum Blocking Factors in Cancer Patients by the Leucocyte Adherence Inhibition Test

The leucocyte adherence inhibition (LAI) test, previously described for the detection of cell mediated immunity and serum blocking factors associated with murine tumours, has now been adapted for use with human cancer patients. Blood leucocytes from these patients, mixed in vitro with antigenic extracts of tumours of the same type, had their normal adherence to glass surfaces diminished. This inhibition was reversed (blocked) by the addition of the patients' own sera. Both LAI and blocking were tumour-type specific, but showed complete cross-reactivity within each type of tumour (melanoma, colon carcinoma, mammary carcinoma). The LAI test could be of great value in diagnosis and evaluation of treatment, since it seems to reproduce consistently the findings made by more elaborate techniques but has the advantage of being simple, rapid and inexpensive.