Lymphokine-activated Killer Cells Treated with Recombinant Interleukin 2 and Circulating Cytokines in Patients with Metastatic Cancer

Treatment with recombinant interleukin 2 and lymphokine-activated killer cells (rIL-2/LAK) has produced a clinical antitumor effect in preliminary human trials. The cytokines -y-interferon (Il'V-y), tumor necrosis factor a (TNF-a), and tumor necrosis factor 0 (TNF-/S, lymphotoxin) have potent in vitro antitumor activity and some clinical toxicities similar to interleukin 2 (IL-2)/LAK. This study sought to determine whether these cytokines were detectable in sera of IL-2/LAK-treated patients, l'en patients were treated with a protocol of 5-day i.v. rIL-2 bolus priming (10! units/kg, every 8 h), followed by 5 daily phereses with harvested lymphocytes cultured in vitro to generate LAK, and 5 days of rIL-2 bolus with infusion of LAK cells. Five patients were treated with a protocol modified to a 3-day rii.-2 prime and 6-day continuous infusion rl L-2 (3 x 10"units/mVday) with infusion of LAK cells. Serum specimens were obtained prior to and 0.5, 2, 3, and 5 h after II -2 or LAK cell administrations. ll-'N-->was detected by enzyme-linked immunosorbent assay, TNF-a by WEHI 164 bioassay or enzyme-linked immunosorbent assay, and TNF-/3 by WEHI 164 cell bioassay. During the prime, few patients manifested in vivo detectable serum cytokines: 11V->, three of ten, 5-day prime (1.03 ±0.46 ng/ml), and zero of five, 3-day prime; TNFa, one of ten, 5-day prime, and one of three, 3-day prime; TNF-0, one of ten, 5-day prime. The supernatants of in vitro LAK generation cultures had detectable levels of cytokines at 24 h which increased progressively until culture harvest at Day 4 (IFN-7, 2.56 ±0.34 ng/ml; TNF-a, 356 ± 110 pg/ml; TNF-0, 8.2 ±4.4 units/ml). The highest levels of in vivo serum cytokines occurred following LAK cell infusion and were more often elevated in patients receiving rIL-2 by bolus than by continuous infusion: Il-'V-y, four of six bolus, zero of three continuous infusion; TNF-a, six of six bolus (maximum 679 pg/ml) versus two of three continuous infusion (maximum, 106 pg/ml). LAK cells in vitro responded with cytokine release on stimulation by tumor cell lines (I l-'V-y, 0.88 ± 0.06 ng/ml; TNF-a, 426 ±16 pg/ml; TNF-/3, 0.64 ±0.06 units/ml). In summary, this preliminary study has detected circulating cytokines in sera of patients receiving IL-2/LAK therapy. The greatest cytokine elevations followed LAK cell infusion. Further studies are warranted to delineate the relative effects of various therapeutic regimens on cytokine levels and possible correlation with toxicity and clinical response.