Seroprevalence for Toxoplasma Gondii in Allogeneic Hematopoietic Stem Cell Transplantation Recipients

Introduction:

Toxoplasmosis is a rare but serious and life-threatening infection following Allogeneic Stem Cell Transplantation (Allo-HSCT). The main cause of toxoplasmosis is the reactivation of latent infection in pre-transplant seropositive patients. In our study, our aim is to present toxoplasma gondii seroprevalence in our center.

Patients and Methods:

A total of 251 allogeneic stem cell transplant recipient were evaluated retrospectively from 1998 to 2015. During Allo-HSCT preparation procedures all recepients were serologically tested. Donor serology records were not adequate. Toxoplasma gondii-specific IgG and IgM antibodies were determined by Chemiluminescence by ARCHITECT lab analyzers using commercially available kits (Abbott, USA). All patients were followed for reactivation.

Results:

Toxoplasma IgG positivity was detected in 51 of patients (20.3%). There was no statistically difference detected between related or unrelated transplants. The mean age of the group was 36 (range 14-71). 144 recipients were male (57%). 208 (83%) patients were transplanted for malign hematological diseases. The majority of patients were grafted from full-matched related donors (173, 69%). The most common source of stem cell was peripheral blood in 192 patients (77%) followed by bone-marrow in 51 patients (51%), bone-marrow plus peripheral blood in 7 patients (2.8%) and cord in 1 patient (0.4%). 192 (77%) patients received myeloablative conditioning regimens. All patients received prophylactic twice weekly trimethoprim/sulfamethoxazole (TMP/SMX) (160/800mg PO daily) after engraftment. Two patients had clinical symptoms of toxoplasmosis however they were seronegative in serology. None of the patients developed an active toxoplasmosis after Allo-HSCT.

Conclusion:

Since less than 30% seropositivity defined as low rate, our institution had low rate seropositivity for Toxoplasma Gondii in Allo-HSCT recipients. Routine use of TMP/SMX prophylaxis and difficulties in diagnosis of toxoplasmosis may lead to low frequency active toxoplasmosis.