Natural killer-like cells found in B-cell compartments of human lymphoid tissues

Natural killer (NK) cells have been implicated in natural resistance to tumours, particularly lymphomas. Recently, they have been implicated in the regulation of human erythropoiesis. The distribution of NK cells in peripheral lymphoid tissues has not been fully documented. NK activity in human or murine lymph nodes is significantly lower than in the spleen or peripheral blood. In Hodgkin's disease, affected lymph nodes and spleens have higher NK activity than non-involved nodes or spleens. Using a monoclonal antibody (Leu 7) that defines the human NK antigen HNK-1 (ref. 8), only a small number of HNK-1+ cells were found in lymph nodes, tonsils or thymus, with greater numbers in the spleen. We report here the topographical distribution of HNK-1+ cells in normal human lymph nodes, tonsils and spleen and preliminary observations in various forms of malignant lymphoma. The most striking observation was that HNK-1+ cells were not distributed uniformly in these tissues but specifically localized in the B-cell compartments (follicular centres).