[The significance of determination of NK cell activity in malignant diseases]

It is considered that NK cells have a major role in the immunosurveillance of the development and spread of tumors so it is of interest to try to determine, not only the basic NK activity of patients with malignant diseases, but also factors that lead to its impairment, as well as therapeutic means of augmentation of NK activity. The results of our study indicate that NK cell activity of breast cancer patients, following surgery, was significantly below NK cell activity of healthy controls. The impaired NK cell activity of breast cancer patients, as our data indicate, could be significantly augmented by, short term, in vitro, cultivation of PBL with low doses of rIL 2. We further found that both healthy sera and autologous sera of breast cancer patients showed a similar degree of inhibition of NK cell activity, after in vitro cultivation of PBL, when compared to PBL cultivated in medium with FCS, and only sera from breast cancer patients with advanced disease had a greater inhibiting effect. We consider that monitoring of NK cell activity after incubation in autologous serum can give a better assessment of NK cell activity of these patients in vivo, and also possibilities of investigating factors which lead to serum-induced modulation of NK cell activity and that preincubation of PBL with immunomodulators, such as IL 2, in in vitro conditions, could give an indication as to whether it is worthwhile proceeding, in the case of each individual patient, with the application of specific immunotherapy.