Lymphocyte subsets in subjects exposed to asbestos: changes in circulating natural killer cells.

Several studies have shown alterations in lymphocyte subsets in the peripheral blood of asbestos workers.' During the past 10 years attention has focused on the role of natural killer (NK) cells, large granular lymphocytes believed to have a role in non-major histocompatibility (non-MHC) restricted cytotoxicity for tumour cells that may result in reduced growth and spread of lung cancer.>4 Studies have shown inconsistent alterations in NK cell numbers, proportions, and activity in various groups of subjects exposed to asbestos.9 In all previous studies CD16 (Leula) was the antibody used to identify theNK cells. Lanier et al' suggested that at least two types of antigens are present on human natural killer cells; Leu-7 (CD57) (identifies human natural killer 1 (HNK-1) cells) and Leu-1 la (CD 16) (identifies natural killer cells 15 (NK 15)). We have investigated lymphocyte subsets including NK cells using both CD 16 and CD57 antibodies in patients with asbestosis, in asbestos workers without asbestosis, and in a control group.