BONE-MARROW BIOPSY IN HAIRY-CELL LEUKEMIA (HCL) PATIENTS - HISTOLOGICAL AND IMMUNOHISTOLOGICAL ANALYSIS OF 46 CASES TREATED WITH DIFFERENT THERAPIES

Serial bane-marrow biopsies were obtained from 46 hairy cell leukaemia (HCL) patients at different time intervals during the course of their disease. The patients were treated according to the following schemes : 14 received alpha-lymphoblastoid interferon (alpha-IFN), 112-Chlorod eoxyadenosine (2CdA), and 21 alpha-IFN first, followed by 2CdA. All th e biopsies were studied by immunohistochemical means for the detection of minimal residual disease. The administration of 2CdA produced the highest reduction of both the rumor burden and HC index, with residual hairy cells (HCs) being undetectable at conventional light microscopy in most cases. In addition, 2CdA induced a higher degree of hypocellu larity than alpha-IFN: the reduction in the amount of normal bone-marr ow, however, was less pronounced in patients who had alpha-IFN before 2CdA. Of 9 patients who received both alpha-IFN and 2CdA and were foll owed for more than 2 years, 3 relapsed, while the remaining 6 continue d to show rare HCs 2 years after 2CdA administration.