Abstract: An improved method for treating Class I histiocytosis, Langerhans cell histiocytosis, is disclosed. In accordance with that method, a therapeutically effective amount of a 2-halo-2'-deoxyadenosine is administered to a host mammal such as a human patient having histiocytosis in an amount of about 0.5 to 0.9 mg/kg of body weight over a course of about 5 to 9 days for up to two courses.

Abstract: Processes for the killing of cancerous B cells, and particularly chronic lymphocytic leukemia (CLL) cells are disclosed. In one process, cancerous B cells that do not proliferate when contacted with an immune response-enhancing agent are contacted with an amount of such an agent sufficient to cause peripheral CLL cells to undergo blast transformation and proliferation. The contacted cells are then maintained for a time period sufficient for them to die from that contact. Further contacting of those cells with a cytotoxic amount of an anti-cancer drug or cytotoxic conjugate enhances the death of those cancer cells. In another process, peripheral CLL cells that proliferate on contact with an immune response-enhancing-agent are contacted with a proliferation-inducing amount of such an agent.

Abstract: A process for the treatment of malignant astrocytoma in mammals is disclosed that utilizes a 2-halo-2'-deoxyadenosine derivative as the active treating agent.