The first line of defense of the immune system is typically the white blood cell known as a macrophage, which engulfs micro-organisms. Candida has an ability to convert back-and-forth between yeast and fungal forms depending on its environment.
It’s ability to convert from it’s normal yeast form to it’s invasive fungal form is problematic for the body’s white blood cells. In these photographs, we see candida being engulfed by macrophages in it’s small, round, cellular yeast form and then by converting to it’s branch-like fungal form, it ruptures the membrane of the macrophage, destroying the white blood cell –http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2849426/figure/f2/

This is just one of the many mechanisms that make candida such an amazing and adaptable organism on one hand, and a problematic one on the other.