Immunology and oncology

Adoptive immunotherapy of cancer: biological response modifiers and cytotoxic cell therapy

Immunotherapy has been developed for the treatment of metastatic cancers refractory to conventional therapies. Immunotherapy utilizes immune cells and/or biological response modifiers (BRMs) to induce an anti-tumor response mediated by the patient's immune system. BRMs, including lymphokines and cytokines, are used as single agents or in combination for cancer therapy. Some BRMs, particularly interleukin 2 (IL-2), can activate and expand in vitro lymphocytes with anti-tumor reactivity which will be adoptively transferred to the patient. To enhance the therapeutic effect of immunotherapy, gene therapy is currently under investigation and involves the insertion of cytokine genes in immune cells or in tumor cells. The development and future of cancer immunotherapy will be discussed in this review.

Chemotherapy of malignant tumors--a self-defeating form of immunotherapy?

Chemotherapy of malignant diseases was introduced into clinical practice during the 1940's. The initial response rate to this type of therapy is high in patients with a variety of cancers but the survival rate is affected in only a few patients, mainly in women with choriocarcinoma. Despite intensive research, the percentage of survivors following chemotherapy, for example in patients with small-cell bronchogenic cancer, has remained almost constant during the last 2 decades. The objective of the present paper is to consider the likelihood of immune mechanisms being active both in the regression and again in the later progression of tumor growth observed during treatment with cytotoxic drugs. Such a dual role for immunity appears to be possible. In contrast to most malignant cells in solid tumors, the leucocytes and leukemia cells are highly sensitive to anti-cancer agents. Thereby the drugs become immunosuppressive at a level in serum lower than that required for a direct interference with the proliferative capacity of the cells in a solid tumor. Furthermore, the cytotoxic drugs selectively influence the immune system. In the first phase of treatment the drugs enhance the effect of T-killer cells relatively by reducing blocking activity in serum; the net result being a regression in the tumor volume. However, continued chemotherapy is inconvenient for cancer patients.(ABSTRACT TRUNCATED AT 250 WORDS)