[Peritumoral administered IL-2-induced tumor regression in melanoma. Pilot study]

Since the immune system plays an important role in the rejection of tumours, current tumour therapy includes immunostimulation. This can be done by interleukin 2 (IL-2), which activates T and killer cells and induces lysis of the tumour. Because the intravenous application of IL-2 may have serious side effects, we treated two patients with peritumoral injections in a pilot study. Both patients suffered from multiple cutaneous metastases of melanoma. A total of 31 and 39 x 10(6) IU recombinant IL-2 (Proleukin) respectively was injected in increasing concentrations in one metastasis of each patient. Histologically, almost complete necrosis of the tumour was induced. In comparison with the control specimen, the T-cell-rich infiltrate increased intra- and, in particular, peritumorally. While the ratio of helper to suppressor T cells remained unchanged, the proportions of NK cells, monocytes/macrophages and IL-2-receptor-bearing cells increased. This reaction was restricted to treated metastases. No clinical side effects or laboratory changes were registered apart from local erythema and swelling.