The EP3662 clone of CD1a supports the diagnosis of New World cutaneous leishmaniasis

Abstract

Leishmaniasis is a parasitic disease endemic to many countries throughout the world that is transmitted by the bite of infected female sandflies. Cutaneous leishmaniasis (CL) is one of the three clinical forms of the disease and may present with nodules or plaques that frequently ulcerate. 1,2 On histopathology, 1-to 3-μm rounded amastigotes are identified within enlarged histiocytes. In New World leishmaniasis, a "marquee sign," in which organisms line up around histiocyte borders, may be observed. 2,3 Direct visualization of amastigotes is sometimes limited by cellular debris or other intracellular parasites requiring distinction. 3 Giemsa stain has historically been used to aid in the identification of Leishmania, but provides limited diagnostic utility in routine practice. 1,2 Polymerase chain reaction (PCR) is the gold-standard diagnostic tool for leishmaniasis but is not available in every country in which the parasite is endemic.Recently, CD1a immunostain has been used to identify amastigotes, demonstrating a peripheral "membrane-like" pattern with accentuation in one of the poles, leaving the unstained nucleus in the center. [1][2][3][4][5] The MTB1 clone was shown to be sensitive for the detection of Old World leishmaniasis but was variably sensitive for New World disease. [1][2][3][4] DeCoste et al demonstrated the use of EP3662 in a single case of Old World CL caused by Leishmania infantum with abundant amastigotes. 6 We sought to determine the sensitivity of the EP3662 clone in detecting New World CL. | METHODSAn Informatics for Integrating Biology and the Bedside (I2B2) query was performed to identify patients with CL based on ICD-10 between