Immunocytochemical and immunohistochemical methods as auxiliary techniques for histopathological diagnosis of cutaneous leishmaniasis.

A significant increase in cutaneous leishmaniasis (CL) and its geographic expansion has motivated the development of techniques to help with diagnosis of the disease. Here we describe immunocytochemical (ICC) and immunohistochemical (IHC) techniques for the diagnosis of CL in the laboratory. Polyclonal antibodies and a modified avidin-biotin complex (Ultra Streptavidin(®)) for Leishmania (V.) braziliensis or Leishmania (L.) amazonensis were developed for the present study. In vitro culture and histological sections from experimentally infected tissues were submitted to ICC/IHC techniques. The polyclonal antibody specificity, stability and immunostaining were evaluated. The polyclonal antibodies purified by chromatography (Sephadex(®)) and obtained from L. (V.) braziliensis and L. (L.) amazonensis insoluble antigens presented 83.3% sensitivity, when the presence of antigens was evaluated, i.e., higher than histopathology or any equivalent method (in vitro culture). The polyclonal antibody presented 100% specificity when used against species frequently found in CL lesions. The ICC/IHC techniques developed in the current study were able to recognize amastigotes and antigens from in vivo and in vitro cultures and from biopsies, offering additional help in the diagnosis of CL. This methodology could be beneficially adopted in public health laboratories.