Toxoplasmosis is a rare complication post-SOT, occurring mostly in D+/R- mismatch. However, in highly endemic areas, the disease occurs predominantly in R+ under post-tx immunosuppressive therapy (IS) due to reactivation of quiescent lesions. Seroprevalence of toxoplasmosis in Brazil is up to 80%. This study aimed to describe the clinical and epidemiological profile of toxoplasmosis post-kidney (KTx) or liver transplantation (LTx) in a highly endemic area.

Cases of possible or definitive diagnosis of toxoplasmosis post-KTx and LTx between Jan 2010 and Oct 2014 were retrospectively reviewed. Cases were classified as possible (clinical and/or radiological compatible picture with response to treatment) or definitive diagnosis – post-tx seroconversion among R-; positive toxoplasmosis specific protein-chain-reaction (PCR) in clinical specimens; or confirmed histopathological diagnosis by specific positive immunohistochemistry.

A total of 13 cases (10 post-KTx and 3 post-LTx) were identified, 5 classified as possible and 8 as definitive. Male sex was 40%, median age 40 years and D+/R- mismatch 46%. IS induction was used only for KTx recipients (antiglobulin, 3 cases, basiliximab, 5, and daclizumab, 2). The majority of patients were receiving predinisone plus tacrolimus (plus mycophenolate in KTx recipients) at the time of toxoplasmosis. All patients received 6-months of SMX-TMP prophylaxis post-tx; toxoplasmosis was diagnosed after stopping prophylaxis in all cases. Treatment rejection and cytomegalovirus (CMV) disease up to 6 months pre-toxoplasmosis occurred in 2 and 4 cases, respectively. Average time between transplant and toxoplasmosis was 4 years, range 0.7 – 8 y. Central nervous system was the most prevalent infection site (9/13); the 4 remaining patients had ocular (1 case) or unspecific febrile symptoms. Lymphocytes average 30 days prior and at the moment of toxoplasmosis were 1317 and 1398, respectively. All patients were treated with sulfadiazine plus pirimetamine. The overall mortality was 30%.

Post-tx toxoplasmosis occurred in pre-tx R- and R+. The disease occurred many years after the tx, during a period of lower IS therapy, and additional recognized risk factors (as rejection treatment, CMV disease and lymphopenia before the diagnosis) were not observed.

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