Safety, False-Positive Reactions and Sensitizing Properties of Leishmania Tropica Skin Test Antigen

A Blinded, Placebo Controlled Study Evaluating Safety, False-Positive Reactions and Sensitizing Properties of Leishmania Tropica Skin Test Antigen (LtSTA)

The efficacy of LtSTA as a skin test antigen depends upon the sensitivity and specificity of the product. This study has been designed to measure the skin test responses to 15, 30, or 50µg doses of LtSTA. The measurements of non-specific reactivity due to components of the antigen solution and the product's ability to sensitize lymphocytes of Leishmania naïve persons when administered intradermally. The presence or absence of a local inflammatory response to the first skin test with each of three doses of LtSTA will provide insight on the specificity of the antigen in a naïve population. The local inflammatory response to LtSTA following the first and second repeat skin tests will indicate if the antigen is sensitizing after intradermal administration.

Inclusion Criteria:

• Male or Female in good health;
• Age 18 - 60 years;
• No past history of leishmaniasis or prior participation in a Leishmania study;
• No prior skin test with a Leishmania antigen;
• No occupational, residential, or travel exposure to Leishmania;
• Positive Candin® or Trichophyton skin test (>= 5 mm induration).

Exclusion Criteria:

• History of adult atopic dermatitis, contact dermatitis to multiple agents, unexplained urticaria, or asthma;

• Active allergic rhinitis or conjunctivitis;

• History of allergy or reactions to phenol, polysorbate 80, or glycerol;

• Medications: currently taking (within the last month) antihistamines or recent history of taking (within the last 1 year) corticosteroids, immunosuppressants;

• Splenectomy;

• Active medical disease*;

  *Active Medical Disease: Any active physical or psychiatric condition that may increase the risks associated with participation in the study or interferes with the interpretation of study results. Included chronic medical illnesses are cardiovascular disease, renal insufficiency, chronic respiratory illness, cirrhosis, chronic hepatitis, chronic pancreatitis, chronic diarrhea, malnutrition, malignancy, autoimmune disease, and asthma.

• Pregnancy or lactating;

• Immunization within 4 weeks;

• History of leishmaniasis;

• Occupational exposure to Leishmania;

• Prior participation in a Leishmania study;

• Prior skin test with Leishmania antigen;

• Travel history to Leishmania endemic areas;

• Abnormal screening lab results;

• Keloid scar formation