Molecular Identification, Diagnosis and follow-up of T.cruzi lineages and populations in Chagas Heart disease patients undergoing clinical reactivation after Heart Transplantation

BURGOS JM; DIEZ M; VIGLIANO C; DUFFY T; BISIO M,; FAVALORO L; LEVIN MJ; NAGEL C; FAVALORO R; SCHIJMAN A.G

Thesaloniki Grecia

Simposio; 15 th Symposium on Infectious in the Immunocompromised Host; 2008

International Immunocompromised Host Society (ICHS)

e study h BACKGROUND: End-stage Chronic Chagas heart disease (ChD) caused by T.cruzi involves dilated cardiomyopathy, complex arrhythmias, heart failure and sudden death. Heart transplantation (HT) is a valid treatment for ChD but reactivation of T. cruzi (RA) is the main complication of concomitant immunosupression. Natural T. cruzi populations display different tissue tropisms, growth rates and drug susceptibilities. Their genetic polymorphism supports distinction of two major lineages: T. cruzi I and II. They have been identified from cultured stocks, underestimating diversity and precluding direct association studies of the parasite role with pathogenesis. OBJECTIVES: To follow-up T. cruzi infection and genotype populations associated to heart tropism and RA directly in clinical samples from ChD undergoing HT, using molecular methods. METHODS: 9 ChD pts with a mean follow-up of 907 days (37–2279 d); routine parasitologic tests and PCR of minicircle DNA (kDNA) in blood, cardiac explants, endomyocardial biopsies of the allograft heart and skin lesions. Lineage identification was done by genomic PCR (Lg-PCR) and intra-lineage typing by RFLP-PCR of kDNA. RESULTS: Sections from 7/8 heart explants of ChD were kDNA-PCR+ and 6/7 Lg-PCR+ (2 Tc I, 3 Tc II and 1 both). RFLP-PCR profiles were polymorphic in different pts´ hearts and also among sections of a same explant. Between 1-3 and 1-6 weeks after HT, kDNA-PCR and Lg-PCR turned into positive in the 9 pts, showing recrudescence of infection leading in 6 to patent parasitemia, concomitant with RA within a mean period of 71,6 days.  4/9 ChD had TcI and 5/9 Tc II in blood. Lg-PCR was positive earlier in Tc II than in Tc I infections. 5/6 RA pts developed lower limbs skin lesions and 1 chagasic myocarditis; in 5 pts identical lineages and RFLP-PCR profiles were found in lesions and blood, but 1 case with a mixed infection had Tc II in chagomas and allograft heart and Tc I in blood. RA pts were treated with benznidazole with negativization of  PCR results and remission of clinical manifestations, but in one case a second RA occurred 286 days after end of treatment. CONCLUSIONS: Both lineages are linked to myocarditis causing ChD, revealing a higher frequency of Tc I than expected for the southern cone of America. Tc II displayed higher parasitemias than Tc I. Differential histotropism occurred in pts with mixed infections. This study also underlines the value of PCR for early diagnosis of RA and monitoring of treatment efficacy.  Trabajo Premiado  Trabajo Premiado  Trabajo Premiado ighlights the usefulness of PCR based strategies  for  early diagnosis of reactivation as well as for characterising parasite populations directly in clinical samples associated with forms of disease. ll as for characterising  for  early diagnosis of reactivation as well as for characterising parasite populations directly in clinical samples associated with forms of disease. ll as for characterising parasite populations directly in clinical samples associated with forms of disease.