Serum and acute phase protein modulation of the effector phase of lymphokine-activated killer cells

An understanding of the role that immunomodulatory factors play in the effector phase of lymphokine‐activated killer (LAK) activity is essential for the development of biologic response modifiers for use in the treatment of advanced carcinoma. Fifteen head and neck cancer patients were studied. Single‐donor killer cells activated by recombinant interleukin‐2 (10 U/mL) and induced in either a complete medium or complete medium plus a 10% autologous serum solution were used. Effector phase solutions of 25% autologous serum were used in chromium 51 release assays to determine sera immunomodulation of LAK cell cytotoxicity. Both K562 and squamous carcinoma (MDA686‐Ln) tumor cell lines were tested. Significant effector phase inhibition (EPI) of cytotoxicity occurred in 40% of studied patients. Seventy percent of patients with stage III or IV or recurrent disease exhibited EPI, whereas only 20% of patients with stage I or II disease and 30% of controls did so. EPI of cancer patient serum correlated directly with α1‐antitrypsin, α1‐acid glycoprotein, and C‐reactive protein (CRP) levels (MDA686‐Ln targets) (r = 0.6, 0.7, and 0.6, respectively) (P