A new scenario in the immunohistochemical diagnosis of cutaneous leishmaniasis.

Cutaneous lesions of leishmaniasis are easy to diagnose when clinically obvious or when amastigotes are numerous in the biopsy. However, this is not always the case. In difficult cases, the diagnosis of leishmaniasis requires a reliable tool to identify the microorganisms. The identification of the parasite via microscope has a superior sensitivity to that of culture, and molecular techniques, such as polymerase chain reaction (PCR), highly improve the sensitivity of the diagnosis. Alternatively, immunohistochemistry has emerged as an affordable alternative to PCR. Several laboratories have produced their own antibodies against Leishmania and seem satisfied with the results. Nevertheless, most of these antibodies are not commercialized or standardized. Pathology also welcomed the unexpected positivity of amastigotes with certain clones of anti-CD1a. The latter does not universally stain all species of Leishmania, with a low sensitivity for New World species. In conclusion, although anti-CD1a is a reliable complementary tool in the diagnosis of leishmaniasis, pathologists should familiarize themselves with one of the specific antibodies against Leishmania and globalize its use, standardizing and adapting the technique.