The organisms usually reside within leukocytes although they may also involve nucleated erythroid precursors. Transfusion of blood products containing leukocytes would be expected to carry a higher risk of transmission.
Ways to reduce exposure to toxoplasmosis:
(1) leukoreduction of the product, preferably during product collection
(2) irradiation
(3) use of donors negative for antibodies to Toxoplasma gondii
(4) avoid blood product transfusion if there is an alternative solution
For preparation of a leukocyte concentrate, the third choice may be the only option.
An immuncompromised patient should be monitored for the first 4 to 6 weeks after transfusion of any blood product. The onset of toxoplasmosis is usually 2 to 3 weeks after the transfusion. Early detection allows for early and aggressive therapy.
Differential diagnosis: other sources of toxoplasmosis (new exposure, reactivation, organ transplant, etc).
