Real-time PCR in HIV/Trypanosoma cruzi coinfection with and without Chagas disease reactivation: association with HIV viral load and CD4 level.

Vera Lúcia Teixeira De Freitas,Rita Cristina Bezerra,Elizabeth Visone Nunes Westphalen,Antonio R L Teixeira,Ana Marli Sartori,Karim Yaqub Ibrahim,Maria Aparecida Shikanai-Yasuda,Tatiane Decaris Molina,Sheila Cristina Vicente Da Silva

doi:10.1371/journal.pntd.0001277

Abstract

BackgroundReactivation of chronic Chagas disease, which occurs in approximately 20% of patients coinfected with HIV/Trypanosoma cruzi (T. cruzi), is commonly characterized by severe meningoencephalitis and myocarditis. The use of quantitative molecular tests to monitor Chagas disease reactivation was analyzed.MethodologyPolymerase chain reaction (PCR) of kDNA sequences, competitive (C-) PCR and real-time quantitative (q) PCR were compared with blood cultures and xenodiagnosis in samples from 91 patients (57 patients with chronic Chagas disease and 34 with HIV/T. cruzi coinfection), of whom 5 had reactivation of Chagas disease and 29 did not.Principal FindingsqRT-PCR showed significant differences between groups; the highest parasitemia was observed in patients infected with HIV/T. cruzi with Chagas disease reactivation (median 1428.90 T. cruzi/mL), followed by patients with HIV/T. cruzi infection without reactivation (median 1.57 T. cruzi/mL) and patients with Chagas disease without HIV (median 0.00 T. cruzi/mL). Spearman's correlation coefficient showed that xenodiagnosis was correlated with blood culture, C-PCR and qRT-PCR. A stronger Spearman correlation index was found between C-PCR and qRT-PCR, the number of parasites and the HIV viral load, expressed as the number of CD4+ cells or the CD4+/CD8+ ratio.ConclusionsqRT-PCR distinguished the groups of HIV/T. cruzi coinfected patients with and without reactivation. Therefore, this new method of qRT-PCR is proposed as a tool for prospective studies to analyze the importance of parasitemia (persistent and/or increased) as a criterion for recommending pre-emptive therapy in patients with chronic Chagas disease with HIV infection or immunosuppression. As seen in this study, an increase in HIV viral load and decreases in the number of CD4+ cells/mm3 and the CD4+/CD8+ ratio were identified as cofactors for increased parasitemia that can be used to target the introduction of early, pre-emptive therapy.

Highlights

Chagas disease is endemic in Latin America, where fewer than 8 million people, many of whom live in urban centers, are infected by T. cruzi [1]
Conclusions: qRT-Polymerase chain reaction (PCR) distinguished the groups of HIV/T. cruzi coinfected patients with and without reactivation
This new method of quantitative realtime PCR (qRT-PCR) is proposed as a tool for prospective studies to analyze the importance of parasitemia as a criterion for recommending pre-emptive therapy in patients with chronic Chagas disease with HIV infection or immunosuppression

Summary

Introduction

Chagas disease is endemic in Latin America, where fewer than 8 million people, many of whom live in urban centers, are infected by T. cruzi [1]. HIV/T. cruzi coinfection has been found in urban centers, and HIV infection [2] has spread to regions in which Chagas disease is endemic. Acute Chagas disease is characterized by high levels of parasitemia, which is detected by direct microscopy of fresh buffy coat, a quantitative buffy coat (QBC) test, or a microhematocrit test [5,6]. Most chronically infected patients do not develop clinical symptoms of Chagas disease, but approximately 20–30% suffer from heart and or digestive tract disease [8]. Reactivation of chronic Chagas disease, which occurs in approximately 20% of patients coinfected with HIV/ Trypanosoma cruzi (T. cruzi), is commonly characterized by severe meningoencephalitis and myocarditis. The use of quantitative molecular tests to monitor Chagas disease reactivation was analyzed

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