Th1/Th2 Polarization and Linkage to L. Viannia Infection Outcomes
Condition: Leishmaniasis
MeSH terms: Leishmaniasis
Study type: Observational

Summary: 
      The purpose of this study is to determine what types of cells participate in the defense of
      humans against Leishmania (skin parasites). People 18-70 years of age who have leishmaniasis,
      have healed leishmanial lesions, or are healthy are being invited to participate in this
      study. Approximately 150 people will participate in the study. Participants will be asked to
      provide some general information about themselves and about skin sores, if they have any. A
      skin test will be performed and a blood sample will be obtained. This study involves up to 3
      visits; the first visit will last up to 5 hours and the second visit will last for 30
      minutes. The third visit may be scheduled within 3 days after the second visit.
    

Detailed description: 
      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.
    

Observational model: Other
Time perspective: Prospective
Sampling method: Non-Probability Sample
Study population: 
        -  Age between 18-70 years

               1. Historical and confirmed cases of chronic leishmaniais disease with no current
                  leishmaniasis

               2. Historical cases of confirmed recurrent leishmaniasis disease 3 Asymptomatic
                  infection cases: (Resident of endemic area, PBMCs responsive to leishmanial
                  antigen)

             4. Healthy donors:

          -  No history or evidence of exposure to transmission of leishmaniasis
      
Keywords: Leishmaniasis; L. Viannia; Leishmania; Colombia