Toxoplasmosis in kidney transplant recipients: a life-threatening but treatable disease

Toxoplasma infection in kidney donors and transplant recipients from Western Mexico: A one-year follow-up

PURPOSE

Solid organ transplant recipients are highly susceptible to Toxoplasma gondii infection. We aimed to describe the 12-month follow-up risk of seroconversion in renal transplant recipients.

METHODOLOGY

Anti-T gondii antibodies were investigated in donors and recipients of renal transplants. In donors, anti-T gondii were evaluated before transplantation. In recipients, anti-T gondii were monitored over a 12-month period to evaluate potential seroconversion or reactivation. IgG and IgM anti-T gondii antibodies were investigated through enzyme immunoassay and Western blot. Molecular diagnosis was performed on peripheral blood leukocytes using PCR to amplify fragments corresponding to the T gondii B1 gene and the repetitive 529-bp element.

RESULTS

The basal frequency of seropositive IgG anti-T gondii antibodies was higher in donors than in recipients (38.4% vs 25.2%; P = .03). During the 12-month follow-up, the accumulated seroconversion to IgG and IgM antibodies was 3/99 (3.0%), and the accumulated reactivation was 11/99 (11.0%). None of the samples exhibited positivity to T gondii DNA.

CONCLUSIONS

This study showed that there is an increased risk of seroconversion or reactivation in renal transplant recipients over a 12-month follow-up. Our data suggest that prophylaxis with trimethoprim and sulfamethoxazole effectively prevented toxoplasmosis, since neither T gondii DNA nor clinical toxoplasmosis was detected.

Late presentation of toxoplasmosis in renal transplant recipients

Toxoplasma gondii is a rare cause of infection in renal transplant recipients and usually occurs within 3 months of transplantation, this being the period of maximum immunosuppression. We report two cases of toxoplasmosis presenting several years after transplantation. One patient developed Toxoplasma retinitis 4 years after renal transplantation and lost peripheral vision in his affected eye. Another developed cerebral toxoplasmosis 6 years following his second renal transplant but did not survive despite treatment. These cases highlight the need for a high index of suspicion of toxoplasmosis as a potential diagnosis even during the later stages of the post-transplant period as survival is poor without early recognition and treatment.