MALIGNANT HEMANGIOENDOTHELIOMA

Background. The administration of interleukin-2 (IL-2) has recently be en reported to be favorable for treating malignant hemangioendotheliom a (MHE). Methods. Two patients with MHE responded well to intralesiona l injections of recombinant IL-2 (rIL-2) without major side effects. T he purpose of this study was to characterize cells infiltrating the re gressing tumor following rIL-2 treatment. Immunohistochemical studies were performed on biopsy specimens taken from rIL-2-injected lesional skin. Results. It was shown that CD8(+) lymphocytes and CD56(+) natura l killer (NK) cells infiltrated at the rIL-2-injection sites, suggesti ng that these cells contributed to the tumor regression. In addition, MHE cells bore intercellular adhesion molecule-1 (ICAM-1) whose expres sion was augmented bu rIL-2 injections. Conclusions. These findings su ggested, that rIL-2 not only induces lymphokine-activated killer (LAK) cells and NK cells, but also facilitates these cytotoxic cells to adh ere to MHE cells by enhancing ICAM-1 expression of tumor cells.