Modulation of the Expression of Major Histocompatibility Antigens on Splenic

The mechanism of action responsible for the beneficial effect of alpha-interferon (a-IFN) in patients with hairy cell leukemia (HCL) is still unknown. Direct antineoplastic and immunomodulating effects on both the host immune system and the hairy cells themselves have been implicated. To evaluate whether lymphokines have any regulatory effect on antigens of the major histocompatibility complex (MHC) on hairy cells and whether this corresponds to prognostic clinical parameters. we studied splenic hairy cells from ten previously untreated patients. The samples were incubated with recombinant human a-IFN, gammaIFN (‘y-IFN). and interleukin-2 (IL-2). In an indirect staining procedure. cells were labeled with monoclonal antibodies (MoAb) to HLA ABC and HLA DR surface structures and subjected to cytofluorimetric analysis. Results concerning the expression of MHC class I and HLA DR antigens were