In vivo migration of labeled autologous natural killer cells to liver metastases in patients with colon carcinoma

Background Besides being the effectors of native anti-tumor cytotoxicity, NK cells participate in T-lymphocyte responses by promoting the maturation of dendritic cells (DC). Adherent NK (A-NK) cells constitute a subset of IL-2-stimulated NK cells which show increased expression of integrins and the ability to adhere to solid surface and to migrate, infiltrate, and destroy cancer. A critical issue in therapy of metastatic disease is the optimization of NK cell migration to tumor tissues and their persistence therein. This study compares localization to liver metastases of autologous A-NK cells administered via the systemic (intravenous, i.v .) versus locoregional (intraarterial, i.a .) routes. Patients and methods A-NK cells expanded ex-vivo with IL-2 and labeled with 111 In-oxine were injected i.a . in the liver of three colon carcinoma patients. After 30 days, each patient had a new preparation of 111 In-A-NK cells injected i.v . Migration of these cells to various organs was evaluated by SPET and their differential localization to normal and neoplastic liver was demonstrated after i.v . injection of 99m Tc-phytate. Results A-NK cells expressed a donor-dependent CD56 + CD16 + CD3 - (NK) or CD56 + CD16 + CD3 + (NKT) phenotype. When injected i.v ., these cells localized to the lung before being visible in the spleen and liver. By contrast, localization of i.a. injected A-NK cells was virtually confined to the spleen and liver. Binding of A-NK cells to liver neoplastic tissues was observed only after i.a . injections. Conclusion This unique study design demonstrates that A-NK cells adoptively transferred to the liver via the intraarterial route have preferential access and substantial accumulation to the tumor site.