Immunohistochemical assessment of respiratory viruses in necropsy samples from lethal non-pandemic seasonal respiratory infections.

do Carmo Debur, Maria; Raboni, Sonia Mara; Flizikowski, Fabiane B Z; Chong, Débora C; Persicote, Ana Paula; Nogueira, Meri B; Rosele, Luine V; de Almeida, Sergio Monteiro; de Noronha, Lucia

BACKGROUND/AIM Acute respiratory infections are an important cause of childhood morbidity and mortality throughout the world, and viruses have often been reported to be an aetiological agent. This study aimed to identify respiratory viruses in paraffin-embedded samples of paediatric lung necropsy specimens, using immunohistochemistry on tissue microarray slides. METHODS Retrospective study in 200 lung tissue samples from children who had died from severe respiratory infections during 1985-2005. Immunoperoxidase assay was performed to detect the viruses that were most commonly associated with respiratory tract infections: influenza virus A (FLU A), influenza virus B (FLU B), respiratory syncytial virus (RSV), adenovirus (AdV) and parainfluenza virus (PIV) types 1, 2 and 3. RESULTS Viruses were detected in 71 (35.5%) cases. Most positive cases were observed in children younger than 6 months. In 42.3% of cases, only one virus was detected: 11 (36.7%) RSV; 7 (23.3%) AdV; 4 (13.3%) PIV2; 3 (10%) FLU A; 2 (6.7%) FLU B; 2 (6.7%) PIV3; and 1 (3.3%) PIV1. Co-infection with more than one virus was observed in 41 (57.7%) cases. No positive correlations were observed between the presence of viral antigens and seasonality of the infection, sex, age or histopathological findings. CONCLUSIONS Non-pandemic seasonal respiratory viruses are involved in a significant number of deaths in paediatric patients; these findings highlight the importance of laboratory investigation of these agents in patients hospitalised with severe acute respiratory infections.