Experimental candidiasis in neutropenic dogs: tissue burden of infection and granulocyte transfusion effects

Abstract

Neutropenic dogs with systemic candidiasis were studied to establish quantitative relationships between tissue burdens of microorganisms and the kinetics of transfused granulocytes. Three groups of dogs rendered neutropenic by chemotherapy were evaluated. Group I consisted of 8 control dogs that were not challenged with Candida albicans; group II, 6 dogs challenged with 106 C. albicans; group III, 7 dogs challenged with 107 C. albicans. Granulocytes obtained from random donors were transfused 24 and 48 hr after fungal challenge in groups II and III and at comparable times in noninfected controls. Serial granulocyte counts obtained following each transfusion were compared for 1-hr increments and half-time disappearance (T½). At autopsy, 24 hr following the last transfusion, tissues were quantitatively assayed for C. albicans. Control animals demonstrated no evidence of infection at autopsy, while disseminated candidiasis occurred in group II and III dogs. Group II dogs showed granulocyte increments at 1 hr of 682 ± 85/cu mm and a circulating half-time of granulocytes of 4.0 ± .4 hr, not significantly different from controls. A reduction in increments at 1 hr (218 ± 46/cu mm) and shortened T½ (2.1 ± 0.3 hr) occurred in the more heavily infected dogs of group III (p