Reduction of active natural killer cells in patients with atopic dermatitis estimated at the single cell level

The natural killer cell cytotoxicity of peripheral blood lymphocytes from twenty-one patients with moderate to severe atopic dermatitis was studied directly by a single cell assay. Suspensions of conjugated effector cells bound to target cells were examined with a light microscope to evaluate the cell lysis using trypan blue exclusion. The binding to the K562 target cells and the kinetics of lysis were normal among the patients' lymphocytes, but the percentage of active natural killer cells in the conjugates and the lymphocyte population was found to be significantly reduced. Our results raise the possibility that the number of active natural killer cells may be reduced and/or modulated by enhancing and suppressing signals in patients with atopic dermatitis.