Quantitative Kinetoplast DNA Assessment During Treatment of Mucosal Leishmaniasis as a Potential Biomarker of Outcome: A Pilot Study

Abstract

Abstract. Mucosal leishmaniasis (ML) is a disfiguring manifestation of Leishmania (Viannia) infection. We evaluated parasite load (PL) over time as a potential biomarker of treatment outcome in ML. PL was assessed with kinetoplast DNA quantitative real-time polymerase chain reaction (kDNA-qPCR) at enrollment, days 14 and 21-28 of therapy and 3, 6, 12-18, and 18-24 months after treatment of ML and correlated to demographic, clinical, and parasitologic factors. Forty-four patients were enrolled: 30 men and 14 women. Enrollment PL differed significantly by causative species (P < 0.001), and was higher in patients with severe ML (nasal and laryngeal involvement) compared with those with only isolated nasal involvement (median = 1,285 versus 51.5 parasites/μg tissue DNA; P = 0.005). Two patterns of PL emerged: pattern 1 (N = 23) was characterized by a sequential decline in PL during and after therapy until kDNA was undetectable. Pattern 2 (N = 18) was characterized by clearance of detectable kDNA during treatment, followed by an increased PL thereafter. All patients who failed treatment (N = 4) demonstrated pattern 1. Leishmania (Viannia) braziliensis was overrepresented among those with pattern 2 (P = 0.019). PL can be quantified by cytology brush qPCR during and after treatment in ML. We demonstrate that treatment failure was associated with undetectable PL, and L. (V.) braziliensis infection was overrepresented in those with rebounding PL.

Cutaneous and mucocutaneous leishmaniasis in travellers and migrants: a 20-year GeoSentinel Surveillance Network analysis

“…Almost three-quarters of travellers with MCL in this analysis were male, a finding that has been documented previously 29,46 and may be explained by increased susceptibility, 46 or by a higher likelihood of riskier 'adventure' travel. Other known and postulated risk factors for the development of MCL include large lesions, head and neck localization, lesions present for > 4 months, micronutrient deficiency and immunosuppression, 38,46 none of which were assessed in this analysis.…”

“…2 Among previously untreated patients with CL, 41% developed ML compared to 3% of patients treated with a systemic antileishmanial regimen. 2 The true risk of late mucosal involvement following CL in travellers is difficult to estimate for several reasons, including the lack of accurate denominator due to the infrequent and self-healing nature of much CL, the prolonged follow-up of travellers required to estimate the incidence of mucosal involvement 28,29 , the years-long latency of MCL potentially contributing to a lack of perceived association with specific prior travel and a potential selection bias towards inclusion of more complicated, persistent and relapsing forms of CL. 30 The Andean countries of Peru and especially Bolivia appear to carry the highest relative risk of MCL following CL due to L. V. braziliensis.…”

“…Although all cases of MCL where causative species was recorded were due to L. V. braziliensis in this analysis, echoing the findings of others, 2 non-braziliensis species including L. V. panamensis and L. V. guyanensis, both well represented in this analysis, accounting for over a fifth of those with CL and species identification, have also been associated with MCL. 29,44,45 Again, it is unknown if nonbraziliensis strains acquired in the at-risk regions of northern South America or Central America will confer risk of future MCL in travellers, as anecdotal clinical experience suggests that it is uncommon. Prospective long-term studies are required to fill this knowledge gap.…”

Tracking of quiescence inLeishmaniaby quantifying the expression of GFP in the ribosomal DNA locus

“…These latent infections can extend during the lifespan of the host and constitute a reservoir for reactivation of the disease in an unpredictable time. This is the case in leishmaniasis, where relapse is common in the absence of drug resistance (22, 23), and complications like muco-cutaneous leishmaniasis or post kala-azar dermal leishmaniasis occur months to years after healing of primary cutaneous or visceral lesions, respectively (24, 25). In other pathogens, in vivo models of subclinical infections have shown evidence that hosts harbor the pathogen in a quiescent stage with no or slow replication (8, 9, 11, 26).…”

Laboratory Diagnosis of Cutaneous and Visceral Leishmaniasis: Current and Future Methods

“…First, in general, patients with ML had a lower parasite burden than localized CL infections, which can interfere with the sensitivity of the assay, as described in a SYBR green-based qPCR assay targeting kDNA to simultaneously detect and quantify L. ( Viannia ) species [ 154 ]. Depending on the causative species, the parasite loading may also be significantly different, with the highest burden in patients with severe ML disease [ 155 ]. Moreover, in patients that did not respond to treatment, a correlation with undetectable parasite loading was found, suggesting that the persistence of the parasite may be due to a limited access to the drugs or localization of the parasites in other tissues/locations not related with the primary infection; in this case the mucosal lesion [ 155 ].…”