Th1/Th2 Polarization and Linkage to L. Viannia Infection Outcomes

The purpose of this study is to determine if Th1/Th2 polarization occurs and is linked to the outcome of infection by L. Viannia (asymptomatic, chronic or recurrent infection). This protocol is the first part of a series of studies that includes protocols 05-0139 and 06-0009. Specific objectives include: defining the expression of human inflammatory cytokines in the ex vivo recall response to live Leishmania for PBMCs of individuals presenting different clinical phenotypes at transcriptional, translational and secretion level; and assessing in situ and circulating cell populations from active, chronic and recurrent patients with respect to differentiation, activation, and co-activation markers. Patients (males and females) aged 18-70 years, with cutaneous leishmaniasis diagnosed in either Cali (CIDEIM) and/or Tumaco (San Andrés Hospital) on the Colombian Pacific Coast, and/or Chaparral, Tolima (San Juan Bautista Hospital) will be invited to participate in the study. Both historic (specific objective 1) and active (specific objective 2) patients will be enrolled. Asymptomatic individuals and healthy donors (controls) will also be invited to participate. Pregnant or breastfeeding women will not be enrolled. A total of 150 participants will be enrolled. For specific objective 1, participants will be asked to provide relevant demographic, clinical and epidemiologic information that will be recorded in a form designed for this purpose. They will also provide blood samples that will be analyzed to determine and compare the expression of human inflammatory cytokines in the ex vivo recall response to live Leishmania of PBMCs between the four groups. Specific objective 2 will be developed in CIDEIM-Cali, only. Participants will be asked to provide skin biopsies in addition to blood samples and relevant information. They will also undergo a skin blister procedure. Samples will be analyzed to characterize and compare in situ and circulating cell populations between the groups. Up to three visits are planned for this objective. The first visit will have a duration of up to 5 hours and the second one will have a duration of 30 minutes. A third visit may be programmed 48h-72h after the second visit for participants undergoing biopsy/skin blister procedure in order to evaluate possible bacterial superinfection and prevent complications. This visit will have a duration of 20 minutes. All visits will take place in a period of 4-5 days. In order to define the expression of human inflammatory cytokines in the ex vivo recall response to live Leishmania for PBMCs of individuals presenting different clinical phenotypes at transcriptional, translational and secretion level, the following variables will be measured and compared among the different groups: levels of expression of transcription factors in cells that have and have not been stimulated by live Leishmania; cytokine concentration at the transcriptional, and secretion levels in cells that have and have not been stimulated by live Leishmania; and percentage of specific PBMCs producing intracellular cytokines at translational level. In order to assess in situ (biopsy and blister) and circulating cell populations from active, chronic and recurrent patients with respect to differentiation, activation, and co-activation markers, the following variables will be measured and compared among the different groups: percentage of infiltrating leukocytes in blister fluid and biopsy, and circulating leukocytes in blood, expressing specific differentiation, activation and co-stimulation markers; mean fluorescence intensities of cells in blood, blister fluid, and biopsy expressing specific differentiation, activation and co-stimulation markers; percentage of specific cells from blister fluid, biopsies and blood producing intracellular cytokines IFN-gamma, IL-10, IL-4 and IL-13; and cytokine concentration in blister fluid.