Resumen de Diagnostic usefulness of immunohistochemical evaluation of CD1a antigen and polyclonal anti-Leishmania antibodies in cutaneous Leishmaniasis
Emilio Lopez Trujillo, Mónica González Farré, Ramón M. Pujol i Vallverdú, Beatriz Bellosillo Paricio, Roser Fisa Saladrigas, Cristina Riera, Ma. Magdalena Alcover Amengual, Carlos Barranco, Gemma Martín Ezquerra
. Background. Different immunohistochemical markers to detect amastigotes in cutaneous Leishmaniasis have been proposed with variable diagnostic usefulness.
Objectives. To evaluate the diagnostic usefulness of immunohistochemical amastigotes identification by specific polyclonal anti-Leishmania antibodies and CD1a expression (clone EP3622) in a series of PCR confirmed cutaneous Leishmaniasis.
Materials and methods. Thirty-three skin samples corresponding to PCR confirmed cutaneous Leishmaniasis were included in the study. All samples were stained with Hematoxylin-eosin and Giemsa.
Moreover, immunohistochemical studies with anti-CD1a and anti-Leishmania antibodies were performed. The patients clinical features and the observed histopathological features were also recorded.
Results. From the selected 33 biopsies, Leishmania spp. amastigotes were detected in 48.4% of cases with conventional Hematoxylin-eosin stain and in 57.5% of cases by Giemsa staining. In 31/33 cases, anti-CD1a allowed us to identify parasitic structures, and in 33/33 cases amastigotes were detected with anti-Leishmania antibodies. Concordance between both techniques, antiCD1a and anti-Leishmania, was 94% [CI 95%: (79,8%- 99,3%)]; p value <0.05. The sensitivity of anti-CD1a in comparison with the PCR was 94%, with a positive predictive value of 100%. Two cases of low parasitic index were negative for CD1a immunostaining. In cases with high parasitic index, anti-CD1a stained amastigotes in superficial and deep dermis. Only a few cases were originally diagnosed with the available histological techniques, needing PCR for Leishmania spp.
identification.
Conclusions. Anti-CD1a antibody seems to be a useful technique to identify amastigotes when PCR and anti-Leishmania antibodies are not available. The sensitivity to detect amastigotes is increased when the CD1a immunostaining is added to the classical Haematoxylin – eosin and Giemsa staining.
