Concanavalin A (Con A) induces movement of its receptors on the cell surface membrane. This induction results in a concentration of Con A site complexes on one pole of the cell to form a cap. A marked difference was found in the mobility of Con A receptor between lymphocytes from normal persons and lymphocytes from patients with
Hodgkin's disease and other
malignant lymphomas. Lymphocytes isolated from tonsils of patients undergoing
tonsillectomy and from axillary lymph nodes of
breast cancer patients exhibited approximately 30% of cells with caps, which is identical with the cap formation ability of normal lymphocytes. In biopsy material from patients with
Hodgkin's disease and other
malignant lymphomas, a significant decrease in the ability of the lymphocytes to form caps was observed. This difference in the mobility of Con A sites was even more pronounced in lymphocytes isolated from the peripheral blood. In 123 patients with
Hodgkin's disease and other
malignant lymphomas, cap formation ranged between 3 and 12%. The ability of cells, from a normal donor or a
lymphoma patient, to form caps was independent of the source from which the lymphocytes were isolated, e.g., lymph node, spleen, or blood. Lymphocytes from patients with
lymphoma were also agglutinated by Con A to a higher degree than normal lymphocytes. These findings are discussed in relation to the association of the lymphocytes with these
malignancies and as a possible aid in their differential diagnosis.