[Natural killer (NK) and lymphokine-activated killer (LAK) activities of a patient recovered from bladder cancer, and the characteristics of LAK cells generated from lymphocyte subsets].

NK and LAK activities of a patient who recovered from bladder transitional cell carcinoma were determined. He was diagnosed in 1980 and operations, radiations and chemotherapies were repeated until 1986. Since 1987, a relapse has not been recognized, and he is now in a tumor free state. Recently, his very high NK and LAK activities were found. The percentage of CD 16+ in his peripheral blood lymphocytes (PBL) was 52.9%, the CD 4- CD 8- CD 16+ was 26.6% (17.5% and 12.1% in control, respectively). It seems likely that his tumor free condition may be related to these high killer activities. As a high number of CD 4- CD 8- cells were included in his PBL, it was possible to generate a CD 4- CD 8(-)-LAK and compare it with the CD 8(+)-LAK. The CD 4- CD 8(-)-LAK exhibited higher killer activity which was maintained for a long period of the culture, and a strong adherence property against the cultured tumor cells. Whereas, the CD 8(+)-LAK did not show such a high level of killer activity which decreased after two weeks into the culture. However, the CD 8(+)-LAK in this patient demonstrated higher killer activity against the auto-tumor cell line compared to what occurred with the control. A type of specific killing against auto-tumor cells may be contained in his CD 8(+)-LAK, although the MHC-restrictive killing was not confirmed. It remains unclear why the killer activities increased in this patient.