Mechanisms of shock in hantavirus pulmonary syndrome.

PURPOSE OF REVIEW: Despite abundant literature on hantavirus, few reports have focused on the shock in hantavirus pulmonary syndrome. This review approaches recent advances that allow us to better understand the pathogenesis of hantavirus pulmonary syndrome shock.

RECENT FINDINGS: Hantavirus pulmonary syndrome has been studied in a hamster model that mimics human shock and respiratory failure. In-vitro experiments show that pathogenic hantaviruses are able to inhibit antiviral responses, and that cytotoxicity of hantavirus-specific T cells enhances the permeability of infected endothelial cells. The idea that the primary cardiac lesion of shock is mostly functional has been shaken by the report of a typical myocarditis in hearts from human hantavirus pulmonary syndrome fatal cases. The involvement of regulatory T cells on hantavirus persistence in its rodent reservoir suggests that these cells could protect from severe hantavirus pulmonary syndrome and shock.

SUMMARY: Hantavirus pulmonary syndrome shock is probably related to an exacerbated immune response of CD8+ T cells producing cytotoxicity on infected endothelial cells, presence of myocarditis and myocardial depression induced by nitric oxide. The virulence elements in G1 glycoprotein could also contribute to shock. Active suppression of immune T regulatory cells is probably involved in hantavirus pulmonary syndrome pathogenesis. These are all new aspects of hantavirus pulmonary syndrome pathogenesis that stimulate further studies to elucidate mechanisms of shock and to develop effective treatment strategies.