[Hematologic changes associated with infection of mice by Cryptococcus neoformans]

The pathogenicity of the L, P and E strains of C. neoformans was studied in 3-5 weeks old CD1 male mice. Cell suspensions containing the most (L), and the least (E) pathogenic strains were inoculated intracerebrally (IC), and intraperitoneally (IP). After 14 days total and differential counts were made for erythrocytes, leukocytes and platelets, yeasts from infected organs were recovered in Sabouraud Dextrose Agar (SDA). The capsular material from C. neoformans was used to stimulate in vivo and in vitro platelet production. Mice inoculated with the L strain, showed increase of neutrophils and platelets, decrease of lymphocytes, the yeast was recovered from spleen, liver and lungs and from brain of mice injected by the IC route. In contrast, strain E produced an increase of neutrophils, reduction of lymphocytes, and was only isolated from the brain of mice inoculated IC. The capsular material stimulated the production and maturation of megakaryocytes only in vitro. The development of the infection and the yeast dissemination were associated with increases in the number of platelets, probably as a result of the stimulant effect of the capsular material on the maturation of megakaryocytes.