PDCD1 and viral infectious disease: The other study utilized whole transcriptome sequencing (RNA-chip and RNA-seq) and other biomolecular methods to analyze and verify remarkable changes of host cells during LPAI and HPAI H7N9 viruses infection, indicating that up-regulated programmed cell death 1 (PD-1) pathways were found to be changed significantly with several highly correlated non-coding RNAs, contributing to high pathogenicity [128].