TY - JOUR T1 - Molecular pathology analyses of two fatal human infections of avian influenza A(H7N9) virus JF - Journal of Clinical Pathology JO - J Clin Pathol SP - 57 LP - 63 DO - 10.1136/jclinpath-2014-202441 VL - 68 IS - 1 AU - Yanling Feng AU - Lvyin Hu AU - Shuihua Lu AU - Qingguo Chen AU - Ye Zheng AU - Dong Zeng AU - Jun Zhang AU - Anli Zhang AU - Liang Chen AU - Yunwen Hu AU - Zhiyong Zhang Y1 - 2015/01/01 UR - http://jcp.bmj.com/content/68/1/57.abstract N2 - Aims To investigate the histopathological manifestations of two fatal cases of H7N9 influenza A virus infection. Methods Pulmonary and hepatic specimens from two fatal cases of H7N9 influenza virus infection were examined using H&E staining. Additionally, in situ hybridisation was performed with probes (ViewRNA) targeting H7N9 RNA and IP-10, interleukin (IL)-6 mRNA. The distribution of surfactant protein A (SP-A), surfactant protein B (SP-B), CD3, CD4, CD8, CD68 and C4d were determined with immunohistochemistry. Results  Apart from the typical diffuse alveolar damage and hyaline membrane observed in severe influenza infection, we detected H7N9 RNA and massive intrapulmonary production of IP-10 and IL-6 mRNA using in situ hybridisation. Hyperplasia of type II pneumocytes was observed by H&E staining and immunohistochemistry. Proliferating macrophages and clustered neutrophils in the infected lungs were observed, whereas T lymphocytes, especially CD4T helper cells, were markedly depleted. No obvious complement deposition was found in lung tissues. Conclusions  Our findings suggest that H7N9 influenza virus induced an immunological response towards overt pulmonary inflammation and systemic lymphopenia which led to intense alveolar damage and respiratory failure. ER -