Quantitative and qualitative effects of m-AMSA (amsacrine) on cellular immune components.

The recently developed acridine derivative 4'-[(9-acridinyl)amino] methanesulphon-m-anisidine (m-AMSA) has become one of the preferred agents in the management of acute leukaemia but little is known of its effects on cellular immune components. We evaluated the qualitative and quantitative effects of m-AMSA on immune cell numbers and function, during both the leucopenic and myelorestorative phases, following intermittent high-dose therapy. Cell-mediated and inflammatory responses were depressed in the treated animals during the leucopenic phase but restoration of immune capability paralleled the recovery of circulating leucocyte numbers. Additionally, m-AMSA displayed unexpected immunomodulatory features: thymus-dependent antibody and delayed-type hypersensitivity responses were actually increased, suggesting the potential of m-AMSA as an immunoregulator in clinical and experimental studies.