Immunologic competence of regional lymph nodes in patients with breast cancer.

In 24 patients undergoing radical mastectomy, the degree of sensitization to breast cancer was compared between lymphocytes obtained from regional lymph nodes and circulating lymphocytes. Using the direct lymphocyte migration inhibition assay a greater immunologic response was observed in regional lymph node lymphocytes as compared to circulating lymphocytes when challenged with breast cancer antigen in vitro. In the breast cancer group, migration inhibition (M.I.) was 21% plus or minus 3% in the regional lymph node (R.L.N.) lymphocytes, as compared to 7% plus or minus 3% in the peripheral blood (P.B.) lymphocytes (p smaller than .01). In the control group M.I. was - 10% plus or minus 2% in the R.L.N. lymphocytes, as compared to - 2% plus or minus 3% in the P.B. lymphocytes (p equal to n.s.) indicating no immunologic response to the breast cancer antigen. A significant delayed hypersensitivity response (M.I.greater 20%) was found in 17/24 regional lymph nodes of the radical mastectomy graoup, as compared to 7/24 in the peripheral blood samples tested in the same group, indicating a superior immune response in the regional lymph node lymphocyte population. These data support the concept that regional lymph nodes in breast cancer patients are immunologically competent, and that the lymphocytes in these nodes are more reactive with a tumor antigen than are the circulating lymphocytes.