Resumen

CAMPOS, S; FIGUEREDO THIEL, S; BELLASSAI, J  y  RODRIGUEZ, I. Immunohistochemistry in the diagnosis of yellow fever: Experience in the Department of Pathology, Health Sciences Research Institute and the Department of Pathology, Faculty of Medical Sciences, National University of Asuncion. Mem. Inst. Investig. Cienc. Salud [online]. 2009, vol.7, n.1, pp.33-39. ISSN 1812-9528.

Yellow fever (YF) is an acute hemorrhagic disease, which is immuno-preventable, caused by an arbovirus whose target organ is the liver. It occurs epidemically and in two epidemiological forms: urban and wild, both with clinical and histopathological similar characteristics. Several methods are used for the diagnosis such as serology, cell culture, molecular biology, histopathology and immunohistochemistry (IHC). The IHC determines the presence of the viral antigen causing the disease at tissue level in post-mortem samples through a highly specific antigen-antibody binding. The objective of this study was to determine the presence of the YF viral antigen by IHC in the liver tissue of deceased patients with suspicion of YF in Paraguay. This is a descriptive study carried out on liver tissue samples (paraffin blocks), obtained post-mortem with the permission of the relatives, of four patients that died and had clinical suspicion of YF. Paraffin blocks were sent, coded to respect the patient confidentiality, by the Department of Pathology of the Faculty of Medicine-National University of Asunción (UNA) to the Department of Pathology of the Instituto de Investigaciones en Ciencias de la Salud (IICS-UNA) to be analysed by IHC. The anti-yellow fever primary antibody and the technique of avidin-biotin-peroxidase complex were used. Also, samples of positive and negative controls for each case were added. Positive staining was evaluated by optical microscopy, and in relation to the histopathological findings those with a brown staining in the cytoplasm of the hepatic cells were considered positive. Positivity was observed in all suspected cases and positive controls. The negative controls did not show any staining. The IHC techniques together with other laboratory techniques and the clinical criteria contribute to postmortem diagnosis in YF cases and represent a useful diagnostic tool which allows the performance of retrospective diagnosis in those cases where other studies could not have been made.

Palabras clave : Immunohistochemistry; yellow fever; tissue; antigen.

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