Experiences with Leukocyte Adherence Inhibition in Human Cancer

The original hemocytometer leukocyte adherence inhibition technique has been used to study immunological reactivity of patients with a variety of tumors. Cellular activity was closely correlated with exposure to tumor of the appropriate type. Specificity and sensitivity in terms of having few false positives and false negatives were of the order of 90% or greater, and repeated testing of the same patients showed a high degree of reproducibility. Patients with tumors showed specific leukocyte reactivity at all stages of tumor growth, and there was no “eclipse” phase even in very advanced disease

Quantitation of anti-tumor cell-mediated immunity by a lymphokine-Dependent reaction using small volumes of blood

A two-stage modification of the leucocyte adherence inhibition (LAI) test is described, which quantitates cell-mediated immunity (CMI) in vitro with 0.5-ml samples of blood from mice exposed to methylcholanthrene-induced tumors. The total blood cells are washed and incubated for 30 min with tumor antigen, then centrifuged, and the supernatant assayed in the LAI test with normal peritoneal cells. The first stage of the reaction depends on the rapid formation of a soluble mediator which appears to be a lymphokine. By this method, the daily changes in specific CMI were followed in individual mice after syngeneic tumor transplantation

Leukocyte adherence inhibition and specific immunoreactivity in malignant melanoma

The leukocyte adherence inhibition (LAI) test has been used to assess specific anti‐tumour immunoreactivity in 80 patients with malignant melanoma, 21 of whom had apparently been successfully treated by surgey, and 44 control subjects. Reaction with melanoma extracts in vitro enabled the activity of blood leukocytes to be detected by inhibition of their adherence to glass, while serum was tested for factors which modified this inhibition. Of the patients with tumours (ranging from primary melanoma in situ to advanced disseminated disease), 22/24 had active leukocytes and 50/58 had serum blocking factor; two of the sera, from patients with regressing tumours, were unblocking. After surgery with no clinical recurrence, leukocytes continued to be active except when tested several years after operation. Blocking factor rapidly disappeared in 16/20 patients tested, and in several patients examined serially the serum became unblocking. In three cases, persistence of serum blocking was followed by clinical diagnosis of metastases. Leukocyte activity was never detected in control subjects (0/10), many of whom had other kinds of tumours or skin lesions. Blocking activity in serum was found in only 3/38 controls with no history of melanoma (1 had a fibrosing cellular blue naevus and 2 had liver disease). Thus the LAI test correlated well with clinical and pathological findings, and shows great promise for the reliable, rapid and specific immunodiagnosis of malignant melanoma

Specific Immunodiagnosis of Hepatocellular Carcinoma by Leucocyte Adherence Inhibition

The leucocyte adherence inhibition test provides a rapid, reliable, and specific technique for the immunodiagnosis of primary hepatocellular carcinoma (malignant hepatoma). The patient's blood leucocytes are tested in vitro for cell-mediated immunity against tumour-associated antigens and the serum is tested for blocking factor which interferes with the immunological reaction. Specific reactivity of both leucocytes and serum was consistently detected in patients with malignant hepatoma, and negative reactions were obtained in other liver diseases including secondary tumours of the liver. The test has provided positive evidence for the presence of hepatoma when more conventional methods gave doubtful or negative results. A positive result preceded the clinical appearance of tumour by up to three years in two patients