Unlike in orthotopic heart transplant (OHT) setting where toxoplasma prophylaxis is a standard practice in pretransplant toxoplasma seronegative recipients who have received donor hearts from seropositive donors (D+/R-), there is no consensus regarding prophylaxis in non-OHT recipients.
The incidence of toxoplasma disease in non-OHT recipients is less than 1% but its true burden is underestimated. Among 31 cases of toxoplasma disease reported from 2004 through 2017, renal and liver transplant recipients comprised of 90% of cases. A total of 94% of 18 recipients with known pretransplant serology were seronegative recipients (mostly D+/R-). Out of 16 recipients with adequate information, 10 (63%) and five (31%) were deemed to be donor derived and nondonor-derived primary toxoplasmosis respectively. Tissue invasive reactivation was uncommon. Almost all cases were described in patients not on prophylaxis at the time of presentation. Universal screening of donor/recipient toxoplasma serology for risk stratification is beneficial as illustrated by reports of fatal cases of toxoplasmosis due to unavailability of positive donor serology results.
Toxoplasma disease in non-OHT predominantly occurs in pretransplant seronegative recipients- mostly in D+/R- group and is rare in seropositive recipients. Posttransplant prophylaxis should be targeted against the high-risk D+/R- group and should be considered in seropositive recipients in whom unusually high immunosuppression is implemented. Toxoplasma serologies and PCR should be used in combination for the diagnosis of toxoplasmosis in non-OHT patients.
aDepartment of Medicine, Carver College of Medicine
bDivision of Infectious Diseases, Carver College of Medicine, University of Iowa, Iowa City, Iowa
cDivision of Infectious Diseases and Geographic Medicine, Stanford University, School of Medicine, Toxoplasma Serology Laboratory, National Reference Center for the Study and Diagnosis of Toxoplasmosis, Palo Alto, California, USA
Correspondence to Jose G. Montoya, MD, Division of Infectious Diseases and Geographic Medicine, Stanford University, School of Medicine, Toxoplasma Serology Laboratory, National Reference Center for the Study and Diagnosis of Toxoplasmosis, Palo Alto, CA, USA. E-mail: firstname.lastname@example.org