Benznidazole Therapy Post-Heart Transplant and Surveillance Trypanosoma cruzi Testing with Donor Specific Antibodies

Abstract

Introduction Chagas disease (Trypanosoma cruzi infection), endemic throughout Latin America, has grown in geographic distribution due to changing migration patterns. While benznidazole (BZN) therapy (5 mg/kg/day x 60 days) is considered first-line treatment, data describing use in recipients of orthotopic heart transplant (OHT) are limited. As opposed to waiting for evidence of circulating parasite or presence on endomyocardial biopsy, our center treats based on PCR detection. Case Report A 48 year-old El Salvadoran immigrant with nonischemic cardiomyopathy and IgG positive, IgM negative T. cruzi serologies underwent OHT complicated by 2R acute cellular rejection at one month post. Maintenance immunosuppression included tacrolimus (goal 10-12 mcg/L), mycophenolate mofetil 1000 mg twice daily, and prednisone 5 mg daily. Surveillance T. cruzi PCR and blood smears were conducted weekly x 2 months, biweekly x 1 month, then monthly. Due to 3 consecutive positive, rising PCRs (Ct value from 27 to 34), BZN therapy was initiated 6 months post. Blood smears were negative at all time points. Given his immunosuppression, treatment goal was suppressive rather than curative. After 8 weeks of BZN therapy, repeat PCR testing remained negative. Of note, the reactivity of his Class I Cw4 increased from a mean fluorescence intensity (MFI) of 1600 pre-OHT to 3200 at 4 months after BZN therapy. However, due to institutional MFI cutoffs for de novo donor specific antibodies (DSA), these were classified as an increase in donor specific reactivity. His Class II DSA remained negative. The patient remains stable and is monitored via DSA and T. Cruzi PCR every 6 months. Summary IgG positive, IgM negative immunocompromised patients can develop asymptomatic T. cruzi reactivation, hence the vital role of surveillance PCR-based detection post-OHT. BZN therapy post-OHT appears to be effective for control of infection despite immunosuppression. Continued evaluation of DSA may be warranted post-BZN treatment.