Background. The evolution of superficial transitional cell carcinoma (TCC) of the bladder poses a clinical management problem due to its tendency to recur after initial transurethral resection (TUR). Natural Killer (NK) cells are a distinct subset of lymphocytes that possess the ability to lyse tumor cells without prior sensitization in a nonmajor histocompatibility-restricted fashion. These cytotoxic cells constitute a relevant barrier against the local growth and systemic dissemination of neoplastic diseases.
Methods. The immunomodulatory effect, after TUR of the tumor, of the prophylactic treatment with intravesical instillations of interferon-alpha-2b (IFN-a-2b) upon the NK activity of peripheral blood mononuclear cells (PBMNC) in 17 patients with superficial TCC of the bladder was analyzed using a 4-hour 51sodium chromate ("Cr)-release cytotoxicity assay against both NK-sensitive, or K562, and NK-resistant, or JY, tumor target cells.
Results. There were no significant modifications of the NK activity of PRMNC during the 3 months of IFNa-2b intracavitary treatment ( P > 0.05). However, with respect to their levels before treatment, NK activity in PBMNC at 3 months posttreatment was enhanced significantly in the 14 patients who showed no sign of tumor