Toxoplasma gondii reactivation identified by detection of parasitemia in tissue culture.

Three patients developed acute toxoplasmosis after allogeneic marrow transplantation for treatment of leukemia. In each case, Toxoplasma gondii was isolated from peripheral blood buffy-coat cells inoculated into fibroblast tissue culture after 10 to 39 days of incubation. Serologic studies did not suggest acute toxoplasmosis, but complete autopsies done in two patients showed active invasive disease. Serologic tests done before the transplants showed that these cases resulted from reactivation of latent infection rather than primary disease. Parasitemia is a feature of reactivation toxoplasmosis in immunosuppressed patients that may be identified by recovery of T. gondii from peripheral blood buffy-coat cells in tissue culture.