False positive reaction of the immunohistochemistry technique using anti-BCG polyclonal antibodies to identify Mycobacterium leprae in wild nine-banded armadillos.

The authors studied 66 wild nine-banded armadillos from Brazil. The ear samples were collected and Ziehl-Neelsen or Fite-Faraco stains were performed, as well as immunostaining using polyclonal BCG antibody, to avaluate the presence of the Mycobacterium leprae. The AFB were not detected by the Ziehl-Neelsen or Fite-Faraco staining, neither immunoexpression of the BCG marker. However, many normal structures from the ears of the nine-banded armadillos, such as condrocytes, condroblasts, fibroblasts and endothelial cells, and Gram positive bacteria cocci, showed false positive reaction by the BCG marker. The authors discuss the use of the immunohistochemical studies with the polyclonal BCG antibody to identify M. leprae antigens in wild armadillos.