HEMOPATHOLOGIC CONSEQUENCES OF PROTRACTED GAMMA-IRRADIATION - ALTERATIONS IN GRANULOCYTE RESERVES AND GRANULOCYTE MOBILIZATION

  • 1 January 1980
    • journal article
    • research article
    • Vol. 56  (1) , 42-51
Abstract
Aplastic anemia and myelogenous leukemia are prominent pathologic effects in beagles exposed to continuous, daily low-dose .gamma.-irradiation. Granulocyte reserves and related mobilization functions were sequentially assessed by the endotoxin stress assay during the preclinical and clinical phases of these hemopoietic disorders. Characteristic patterns of granulocyte reserve mobilization are described that reflect given stages of pathologic progression. For radiation-induced leukemia, a 5-stage pattern was proposed. A simple pattern of progressive, time-dependent contraction of granulocyte reserves and mobilization capacity was noted in the development of terminal aplastic anemia. Early preclinical phases of radiation-induced leukemia appear to involve an extensive depletion of the granulocyte reserves (phase I) during the 1st .apprx. 200 days of exposure followed by a partial renewal of the reserves and associated mobilization functions between .apprx. 200-400 days (phase II). Sustained, subnormal granulocyte mobilizations (phase III) following endotoxin stress typify the responses of dogs during the intermediate phase. Late preclinical, preleukemic stages (phase IV) are characterized by a further expansion of the reserves and in the mobilization capacities, particularly of the less mature granulocytes. Such late alterations in the pattern of granulocyte mobilization, together with other noted cellular aberrancies in the peripheral blood and marrow, appear to indicate leukemia (phase V) onset.