Effect of cyclophosphamide on the course of Candida albicans infection in normal and vaccinated mice

To evaluate the immunomodulating effect of cyclophosphamide (Cy) on the course of Candida albicans (C. albicans).

We performed this study in the Shiraz Medical School, Shiraz, Iran during April to November 2003. Five groups of 10 mice (vaccinated group) were immunized by 5 equal injections of 2 x 10(5), 2.5 x 10(5) and 3 x 10(5) of the organism intraperitoneally. Then, the group received Cy on day zero and was challenged with lethal doses of C. albicans (7.74 x 10(5) colony forming unit) on days zero, one, 3, 6 and 12 post-Cy injection. Another 5 equal groups of 10 mice (non-vaccinated group) received Cy on day zero and similar to vaccinated ones were challenged with lethal doses of the organism too. The control groups received just Cy on day zero and were sacrificed on days zero, one, 3, 6 and 12 days post-Cy injection. We performed the hemogram and the spleen and studied the renal tissues microscopically and macroscopically.

In vaccinated group, we observed an increase in survival time and in spleen and renal weights were visible while in non-vaccinated ones, a significant decrease was also observed on days one and 3 and an increased on days 6 and 12 post-Cy injection. We observed atrophy and necrosis in the spleen while inflammation and necrosis were also observed in the kidneys on days one and 3. We noticed a significant hyperplasia in the white pulp on days 6 and 12 post-Cy injection.

We conclude that hyperplasia in the white pulp of spleen and the increase in peripheral polymorphonuclears due to selective effects of Cy could effectively protect the animal against C. albicans infection.