In vitro NK responses of cancer patients (N=21) to rIFN‐αA and rIL‐2 were examined. The serum concentration of IAP (immunosuppressive acidic protein) was determined in parallel. Five out of seven patients whose serum IAP contents were within the normal range (270 μg/ml to 470 μg/ml), had their NK activities significantly augmented by rIFN‐αA and rIL‐2. On the other hand, NK cells from ten out of fifteen patients whose serum IAP concentrations were 650 μg/ml or more, were not activated by rIFN‐αA. NK cells of these fifteen patients yet were capable of responding to rIL‐2. NK cells from cancer patients, however, became responsive to rIFN‐αA by either removal of adherent cells or treatment with indomethacin. Therefore, macrophages in PBMC of cancer patients with high serum IAP levels seem to selectively suppress NK response to rIFN‐αA by an indomethacin‐sensitive mechanisms. It was further shown that PGE2 was not the mediator of this suppression.
|Number of pages||11|
|Journal||MICROBIOLOGY and IMMUNOLOGY|
|Publication status||Published - 1992 Oct|
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