Impaired immune response in severe human lower tract respiratory infection by respiratory syncytial virus.
| Autor: | Larrañaga CL; Programa de Virologia, ICBM, Facultad de Medicina, Universidad de Chile, Santiago, Chile. clarrana@med.uchile.cl, Ampuero SL, Luchsinger VF, Carrión FA, Aguilar NV, Morales PR, Palomino MA, Tapia LF, Avendaño LF |
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| Jazyk: | angličtina |
| Zdroj: | The Pediatric infectious disease journal [Pediatr Infect Dis J] 2009 Oct; Vol. 28 (10), pp. 867-73. |
| DOI: | 10.1097/INF.0b013e3181a3ea71 |
| Abstrakt: | Background: Respiratory syncytial virus (RSV) is a major cause of acute lower respiratory infection in infants. The immune response plays a leading role in the severity of the disease. We hypothesized that severe RSV disease is associated with an impaired immune response characterized by low circulating T lymphocytes and plasma cytokine concentrations. Methods: We evaluate the in vivo immune responses of previously healthy infants with their first proven RSV-acute lower respiratory infection that required hospitalization. According to the clinical severity, defined by using a strict scoring system, the in vivo immune response was compared through the analysis of plasma cytokine values and the phenotyping of peripheral blood lymphocyte and natural killer (NK) cells. Results: Absolute blood cell counts of CD4+, CD8+, and CD19+ lymphocytes and NK cells were lower in subjects with RSV than in control infants. Lowest cell counts were observed in more severe RSV-infected infants. Significant low values were obtained in CD8+ lymphocytes (P = 0.03) and nonactive NK cells, that express CD94 antigen (P = 0.046). In contrast, activated NK cells that do not express CD94 molecules were significantly higher in RSV infected infants than in healthy controls (% of cells: P = 0.004). The interferon-gamma and tumor necrosis factor-alpha values in RSV infected patients were lower than in controls subjects. Interleukin-17 cytokine was not detected in healthy infants and the largest concentration was found in moderately ill patients as compared with severe cases (P = 0.033). RSV infection showed significantly higher interleukin-8 chemokine than in control infants (P = 0.024). Conclusion: We propose that severe RSV infection in very young infants is associated with poor blood proinflammatory cytokine production, low counts of CD8+ T cells and with a greater activity of a group of NK cells, that are independent of the major histocompatibility complex class Ib recognition system. |
| Databáze: | MEDLINE |
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