Quantification of Parasite Load in Clinical Samples of Leishmaniasis Patients: IL-10 Level Correlates with Parasite Load in Visceral Leishmaniasis

Abstract

A rapid and accurate method to detect and quantify Leishmania parasite is urgently needed to facilitate early diagnosis of Leishmaniasis and monitoring of antileishmania therapy. In this study, real-time assay was applied to estimate parasite load in clinical samples of visceral leishmaniasis (VL) and post kala-azar dermal leishmaniasis (PKDL) patients. The mean parasite load in blood of VL patients (n = 31) was 8,372 parasites/ml, while the mean parasite load in bone marrow aspirate (BMA) was 194,962 parasites/million nucleated cells (n = 12). Parasite load was undetectable after treatment with amphotericin B (n = 9) in VL, while a residual parasite burden was detected in 2 of 6 patients following treatment with sodium antimony gluconate. Further, circulating levels of IFN-γ, TNF-α, IL-10, IL-6, IL-4 and IL-2 were analysed in VL patients (n = 29) by Cytometric Bead Array to evaluate correlation with parasitic load. Interestingly, IL-10 levels correlated significantly with parasite load (r = 0.82, P<0.0001). The mean parasite load in dermal lesions of PKDL patients was 9,502 parasites/µg tissue DNA at pre-treatment stage (n = 25), with no detectable parasites after therapy (n = 5). Parasite burden was distinctly higher (P<0.0001) in nodular lesions (n = 12) (19,586 parasites/µg tissue DNA) compared to papular/macular lesions (n = 13, 193 parasites/µg tissue DNA). Further, chronic PKDL lesions showed significantly (P = 0.0166) higher parasite load in comparison with acute lesions. Results indicate that chronic, nodular cases constitute the major parasite reservoir for anthroponotic transmission. Our results establish that the high parasite load in VL is strongly correlated with a high level of IL-10, implicating IL-10 as a marker of disease severity. The assay is applicable for diagnosis as well as prognosis of both VL and PKDL, providing a simple molecular tool to monitor the efficacy of antileishmanial drugs or vaccines.

Antimony-resistant but not antimony-sensitiveLeishmania donovaniup-regulates host IL-10 to overexpress multidrug-resistant protein 1

“…1 C and D). There are previous reports that patients who have kala-azar and harbor Sb R LD show a much higher parasite burden and much greater IL-10 production compared with those harboring Sb S LD (23,24). This phenomenon of increased parasite burden in Sb R LD-mediated infection may also be an attribute of the terminal glycoconjugates, as shown by KD experiments.…”

“…To determine signaling molecules eventually leading to MDR1 upregulation, Mϕs were infected with either Sb R LD or Sb S LD or treated with rIL-10 (200 pg/mL) for different periods of time (6,12,18,24, and 48 h). When Mϕs were infected with Sb R LD, the IL-10 level showed a slight increase at 18 h, peaked at 24 h (P < 0.0001; four-to sixfold), and remained unaltered until 48 h (Fig.…”

Bone Marrow Parasite Burden among Patients with New World Kala-Azar is Associated with Disease Severity

“…Previous work by Verma and others 44 on parasitemia in Indian post-kala-azar dermal leishmaniasis (PKDL) showed a strong correlation of parasitemia of L. donovani with serum levels of IL-10, suggesting that IL-10 leads to higher parasitemia. This observation is in line with previous data showing the role of this cytokine on the control of L. donovani in or by the spleen.…”

Analysis of the expression of toll-like receptors 2 and 4 and cytokine production during experimental Leishmania chagasi infection

“…It is endemic in 88 countries and affects 12 million people worldwide. The visceral form, caused by Leishmania donovani and Leishmania chagasi, is prevalent in tropical and subtropical regions, with 90% of cases occurring in Bangladesh, Brazil, India, Nepal and Sudan (Desjeux 2001, Goto & Prianti 2009, Verma et al 2010. Leishmania infection may be asymptomatic, oligosymptomatic or progressive and the most severe cases result in splenomegalia, fever, pancytopenia, hypergammaglobulinemia and weight loss ).…”