Partial purification and characterization of a lymphocyte-inhibitory factor(s) in ascitic fluids from ovarian cancer patients.

Recent studies have demonstrated that advanced neoplastic disease is often associated with a general impairment of im mune function (15, 17, 29). High levels of serum immunoreg ulatory factors which nonspecifically inhibit in vitro and in viva lymphocyte function (13, 17, 21 , 25, 28, 39, 40, 45) are thought to account for the depressed immune status of anergic cancer patients (13, 33). Furthermore, the presence of soluble immunosuppressive factors in cell-free ascites and pleural fluids in patients with penitoneal metastatic disease and in ascites fluids from munine tumor models has been well docu mented (2—4, 19, 20, 27, 40—42,46). It has been postulated that tumor cells may locally produce or induce the formation of factors capable of inhibiting lymphocyte function, thus effecting local immunosuppression (3, 4). Hess et al. (19) have demon strated that a substantial number of ascites fluids from ovarian cancer patients contained a nondialyzable, noncytotoxic fac tar(s) with an apparent molecular size of 50,000 to 100,000 daltons which inhibited the in vitro response of normal lympho cytes. However, the presence of lymphocyte-inhibitory activity was not limited to effusions of malignant origin but was also found in a few benign ovarian disorders, suggesting that the presence of lymphocyte antiproliferative factors in these fluids may constitute a natural host-mediated response to inflamma tory stimuli as postulated by LeBien et a!. (22). The relation of the lymphocyte-inhibitory factors found in ascitic effusions to those described in serum remains unclear. The present inves tigations were undertaken to purify and characterize the lym phocyte-mnhibitoryfactor(s) found in ascitic effusions from ovar ian cancer patients.