Morphological and immunohistochemical clues for the diagnosis of cutaneous leishmaniasis and the interpretation of CD1a status

• Published in: Journal of the American Academy of Dermatology 2016-03, Vol.74 (3), p.536-543
• Main Authors: Fernandez-Flores, Angel, MD, PhD, Rodriguez-Peralto, José Luis, MD, PhD
• Format: Article
• Language: English
• Subjects: amastigotes; antigen transfer; Antigens, CD1 - analysis; CD1a; Dermatology; Female; granuloma; granulomatous inflammation; Humans; Immunohistochemistry; Langerhans cell; langerin; Leishmania; Leishmania infantum; Leishmania infantum - chemistry; Leishmania infantum - immunology; Leishmania major; Leishmania tropica; leishmaniasis; Leishmaniasis, Cutaneous - diagnosis; Leishmaniasis, Cutaneous - parasitology; Male; MTB1; transepidermal elimination
• ISSN: 0190-9622; 1097-6787
• DOI: 10.1016/j.jaad.2015.09.038

Background CD1a immunoexpression by amastigotes of Leishmania major and L tropica has been demonstrated. Objective We studied the CD1a and the langerin status of amastigotes in cases of L infantum. Methods We investigated 19 cases of cutaneous leishmaniasis. All cases were immunostained with CD1a, langerin, and CD68. We also studied 4 cases of visceral leishmaniasis. Results We found expression of CD1a by amastigotes in all of these 19 cases. CD1a− amastigotes are found in reticular areas of the dermis. The pattern of CD1a immunostaining of amastigotes is characteristic, with peripheral positivity, a negative nucleus in the center, and reinforcement of the kinetoplast in 1 pole. Leishmania amastigotes were langerin-negative. Visceral Leishmania amastigotes also express CD1a. Limitations Our study was limited because it only included cases of infection by L infantum. Conclusions (1) L infantum is CD1a+ , (2) the pattern of CD1a immunostaining of amastigotes is peculiar, (3) CD1a− amastigotes are found in reticular areas of the dermis, and (4) visceral Leishmania amastigotes also express CD1a.