Immunomodulatory therapy

The rationale for using immunomodulatory therapy in SARS is based on the fact that acute infections in general can stimulate the release of proinflammatory cytokines. In SARS, there may be an excessive host response or cytokine dysregulation. This hypothesis may be substantiated from the observation that clinical deterioration can paradoxically occur despite a fall in the viral load as IgG seroconversion takes place (Peiris et al 2003b), as well as from autopsy findings which demonstrate a prominent increase in alveolar macrophages with hemophagocytosis (Nicholls et al 2003). A tri-phasic model of pathogenesis comprising viral replicative, immune hyperactive and pulmonary destructive phases was thereafter proposed (Peiris et al 2003b; Sung 2003). Intuitively, immunomodulatory therapy carefully applied during the hyper-immune phase may be an important treatment component in SARS.