Abstract: Objective To investigate the changes of peripheral blood cells and C reactive protein (CRP) in patients with avian influenza A(H7N9)virus infection, and provide the relative reference for clinical diagnosis,treatment and monitor. Methods A total of 18 patients with avian influenza A(H7N9)virus infection (H7N9 group) were enrolled in the study, 20 patients with avian influenza A (H1N1)virus infection in 2009 (H1N1 group) were enrolled as control group, and 20 healthy subjects were also enrolled as healthy control group. H7N9 group was sub-classified into mild group (12 cases) and severe group (6 cases). The peripheral blood cells in all groups were quantified, and the serum CRP in H7N9 group was also determined. Results For H7N9 group,the white blood cell (WBC) count did not change much in the early period of infection onset,while the lymphocytes (Lym) decreased significantly when compared with healthy control group (P<0.05),together with the decreasing of platelets (PLT) and eosinophils (Eos)(P<0.05). For the severe group,the neutrophils (Neu) increased significantly when compared with those of healthy control group (P<0.05). However,no statistical significance was observed for all the parameters between the mild and severe groups (P>0.05). The clinical characteristics of peripheral blood cells in H7N9 group were similar with those in H1N1 group in 2009,while the Lym decreased more significantly(P<0.05). The PLT, Lym and Eos all increased significantly after treatment in the mild group when compared with those of pre-treatment(P<0.05). The serum CRP increased significantly in H7N9 group after administration,which was more obvious in the severe group than in the mild group (P<0.05). Similarly,the serum CRP decreased after treatment in the mild group when compared with that of pre-treatment (P<0.05). Conclusions The serum CRP level may be a parameter on distinguishing the mild group from severe group. However,the clinical characteristics of peripheral blood cells in patients with avian influenza A (H7N9)virus infection are similar with those in patients with avian influenza A(H1N1)virus infection in 2009. Clinical information regarding different aspects should be carefully collected for clinical diagnosis, prognosis assessment and prevention of influenza outbreaks.

Key words: Avian influenza A(H7N9)virus, Peripheral blood cell, C reactive protein