In murine models, transgenic chemokine-cytokine tumor vaccines overcome many of the limitations of single-agent immunotherapy by producing the sequence of T-cell attraction followed by proliferation. The safety and immunologic effects of this approach in humans were tested in 21 patients with relapsed or refractory neuroblastoma. They received up to 8 subcutaneous injections of a vaccine combining lymphotactin (Lptn)- and interleukin-2 (IL-2)-secreting allogeneic neuroblastoma cells in a dose-escalating scheme. Severe adverse reactions were limited to reversible panniculitis in 5 patients and bone pain in 1 patient. Injection-site biopsies revealed increased cellularity caused by infiltration of CD4+ and CD8+ lymphocytes, eosinophils, and Langerhans cells. Systemically, the vaccine produced a 2-fold (P =.035) expansion of CD4+ T cells, a 3.5-fold (P =.039) expansion of natural killer (NK) cells, a 2.1-fold (P =.014) expansion of eosinophils, and a 1.6-fold (P =.049) increase in serum IL-5. When restimulated in vitro by the immunizing cell line, T cells collected after vaccination showed a 2.3-fold increase (P =.02) of T-helper (TH2)-type CD3+IL-4+ cells. Supernatant collected from restimulated cells showed increased amounts of IL-4 (11.4-fold; P =.021) and IL-5 (8.7-fold; P =.002). Six patients had significant increases in NK cytolytic activity. Fifteen patients made immunoglobulin G (IgG) antibodies that bound to the immunizing cell line. Measurable tumor responses included complete remission in 2 patients and partial response in 1 patient. Hence, allogeneic tumor cell vaccines combining transgenic Lptn with IL-2 appear to have little toxicity in humans and can induce an antitumor immune response.