Effect of leucocyte interferon on natural killer cells in healthy volunteers

The effect of partially purified human leucocyte interferon on natural killer activity (NK activity) of peripheral blood in six healthy volunteers was tested in this study. After 4 h of intradermal injection of interferon, a rapid transient decline in NK activity and in the number of NK cells (large granular lymphocytes) in peripheral blood was observed. The decline was most distinct at 20 h and recovered at 72 h. Since no clear activation of Nk cells in peripheral blood was detected, the results suggest an extravasation of NK cells as a result of interferon injection. NK cells did not accumulate at the injection site on the skin, because the suction blister fluids over the injection sites did not contain increased numbers of NK cells.