Leukopenia with granulocytopenia in experimental mucormycosis (Rhizopus oryzae infection).

Mucormycosis was produced in rabbits with sustained, severe leukopenia and granulocytopenia induced by repeated injections of nitrogen mustard. Initially, these animals developed extensive fungus lesions at the site of inoculation which later became granulomatous and tended to heal. Only the early phases of host resistance appeared impaired by the virtual elimination of the polymorphonuclear leukocyte as a factor in the host response. Despite the persistent leukopenia and granulocytopenia, the later phases of host resistance resembled those of the normal animal. Thus, the behavior of the infection in this experiment differs greatly from the unchecked progression of mucormycosis in the metabolically abnormal animal with acute alloxan diabetes. The differences in the course of the disease and in the morphologic appearance of the lesions indicate that metabolic alterations in the host affect all phases of host resistance and not only the polymorphonuclear leukocytic response.