Dopa-stained melanocytes in the macular lesions of early leprosy

• Autor(a) principal: Antunes, Sérgio Luiz Gomes
• Data de Publicação: 1996
• Outros Autores: Alves, Samantha Lee Salgueiro, Corte-Real, Suzana, Meireles, Maria Nazaré, Nery, José Augusto da Costa, Sarno, Euzenir Nunes
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Hansenologia Internationalis (Online)
• Texto Completo: https://periodicos.saude.sp.gov.br/hansenologia/article/view/36475

The mechanism of association of hypopigmentation and sensorial loss in a leprosy macular lesions has not been clarified yet. The biopsy of a macular lesion on the medial face of the right forearm of a fourteen-year old male leprosy patient was submitted to DOPA-staining formelanocytes, which is specific for the melanocytic tyrosinase enzyme and it is a proper method for identifying and counting these cells in the skin. A contralateral specimen of the same patient went through the same procedure as a control experiment. The specimen from the macular lesionshowed a higher number of DOPA-stained melanocytes than the control fragment. Dermal melanocytes were present in high amounts in the abnormal specimen. Increased expression of tyrosinase by melanocytes in the macular lesions may reflect a positive feed-back stimulusrepresented by the lack of substrate tyrosine, which may in turn be utilized by the mycobacterial agent. Ultrastructural study of the normal and pathological specimens showed no significant differences in the morphological appearance of melanocytes and their melanosomes. These results suggest that the utilization of phenolic compound by the Mycobacterium leprae may be involved in the mechanism of hypopigmentation. A higher number of cases will be necessary to confirm this hypothesis.