Analysis of localized immune responses reveals presence of Th17 and Treg cells in cutaneous leishmaniasis due to Leishmania tropica.

Purpose: The interaction between the Leishmania parasite and the host cell involves complex, multifaceted processes. The disease severity in cutaneous leishmaniasis (CL) is largely dependent on the causative species. Most of the information on immune responses in human CL is available with respect to L.

Evidence for involvement of Th17 type responses in post kala azar dermal leishmaniasis (PKDL).

Background: Post kala-azar dermal leishmaniasis (PKDL), a dermal sequel of visceral leishmaniasis, caused by Leishmania donovani, constitutes an important reservoir for the parasite. Parallel functioning of counter acting immune responses (Th1/Th2) reflects a complex immunological scenario, suggesting the involvement of additional regulatory molecules in the disease pathogenesis.

Methodology/principal Findings: In the present study, human cytokine/chemokine/receptor specific cDNA array technique was employed to identify modulations in gene expression of host immuno-determinants during PKDL, followed by evaluation of Th17 type responses by analyzing mRNA and protein expression of Th17 markers (IL-23, IL-17, RORγt) and performing functional assays using Leishmania antigen (TSLA) or recombinant (rec)IL-17.

Foxp3 and IL-10 expression correlates with parasite burden in lesional tissues of post kala azar dermal leishmaniasis (PKDL) patients.

Background: Post kala-azar dermal leishmaniasis (PKDL), a sequel to visceral leishamaniasis (VL) in 5-15% cases, constitutes a parasite reservoir important in disease transmission. The precise immunological cause of PKDL outcome remains obscure. However, overlapping counter regulatory responses with elevated IFN-γ and IL-10 are reported.

Quantification of parasite load in clinical samples of leishmaniasis patients: IL-10 level correlates with parasite load in visceral leishmaniasis.

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).