A new perspective on C-reactive protein in H7N9 infections

• Compared with H1N1 virus, H7N9 virus can induce high expression of C-reactive protein (CRP).
• H7N9 patients with high levels of CRP had poor outcomes.
• MIP-1β, MCP-1, IP-10, and IL-6 plasma levels were positively related to CRP levels.
• The plasma IL-17A level had a negative correlation with CRP.
• CRP may be an indicator to assess cytokine storms and identify high-risk cases.

SummaryObjectivesThe avian influenza H7N9 virus can cause cytokine overproduction and result in severe pneumonia and acute respiratory distress syndrome. Many studies have focused on hypercytokinemia during avian influenza infection. This study examined the association between C-reactive protein (CRP) and cytokines.MethodsThe plasma cytokine and chemokine profiles of 57 H7N9 patients were investigated using a multiplex immunoassay. The CRP levels of patients with H7N9 and patients with H1N1 were also compared. Further, the association between cytokines and CRP in H7N9 infections was explored.ResultsCompared with H1N1 virus, it was found that H7N9 virus induced higher expression of CRP, leading to cytokine storms. Several cytokines, including MIP-1β, MCP-1, IP-10, and IL-6, were observed to have significantly positive relationships with CRP levels, whereas IL-17A was negatively associated with CRP levels.ConclusionsThese findings suggest that CRP may be used as an early indicator to identify high-risk patients, to assess disease progression, and to determine the development of hypercytokinemia.