Histological observations on Montenegro's reaction in man

Abstract

The Montenegro skin test is widely used as a diagnostic method for American cutaneous leishmaniasis (ACL) but little is known about the histological changes that occur in the skin after administration of the antigen. This report is based on histological studies of biopsied material obtained, from inoculation sites, 48 hours after individuals had been given intradermal injections with a standardized Montenegro antigen. The material examined was obtained from four distinctly different test groups: naturally infected patients with parasitologically proved ACL and with positive Montenegro's reaction; individuals without previous history of ACL and not previously tested with Montenegro antigen; participants in anti-ACL vaccine trials who developed positive reactions to Montenegro antigen after vaccination; other participants in vaccine trials who had negative Montenegro responses after vaccination or had served as controls in the trials. The histological pictures of each group are described and discussed. Histologically, the reactions of vaccinated individuals were indistinguishable from those with naturally acquired infections.Foi realizado o estudo histológico do material obtido nas biópsias do local de inoculação do antígeno para teste de Montenegro (T.M.) nos seguintes grupos de indivíduos: I) Seis pacientes com leishmaniose cutânea comprovados parasitologicamente, com Montenegro positivo; II) Cinco indivíduos normais, não residentes em zona endêmica, com Montenegro negativo; III) Nove soldados participantes de ensaios clínicos com vacina anti-LTA - MAYRINK e cols. 1979 e que tiveram o TM positivo 35 dias após vacinação. IV) Um último grupo constituído de quatro soldados, também participantes de ensaio clínico com a mesma vacina acima, dois vacinados que não mostraram TM positivo 35 dias após vacinação e dois que receberam placebo. As biópsias foram realizadas 48 hs após a inoculação do antígeno. O material foi fixado em formol à 10% (pH 7.2). Histologicamente, excetivando o grupo II (controle negativo), os grupos I-I1I-IV mostraram diferenças quantitativas no infiltrado mononuclear. Os quadros histológicos de cada grupo são descritos e discutidos