A novel subset of putative stem/progenitor CD34(+)Oct-4(+) cells is the major target for SARS coronavirus in human lung

Chen, Yongxiong; Chan, Vera Sau-Fong; Zheng, Bojian; Chan, Kelvin Yuen-Kwong; Xu, Xiaoning; To, Leo Yuk-Fai; Huang, Fang-Ping; Khoo, Ui-Soon; Lin, Chen-Lung Steve

Collectively, we conclude that the major target for SARS-CoV in the SARS-infected lung is a novel subset of putative lung stem/progenitor CD34 Ï© Oct4 Ï© cells ( Fig. 2 ) , which is also the only cell subset in the fresh non-SARS samples being infected after ex vivo infection ( Fig. 3 B ) . Interestingly, not all of our enrolled non-SARS individuals had detectable putative stem/progenitor cells in the lung. A recent report has shown that approximately one third of SARS-infected patients had self-limited symptoms with no clinical or radiological evidence of progression to pneumonitis, whereas the remaining had progressive deterioration with impaired lung function ( 24 ) . Whether or not our fi ndings may contribute to the above clinical observation deserves further study. It also remains to be investigated if these putative stem/progenitor cells also exist in nasopharynx, throat, or trachea. The presence of these cells in the upper airway may also allow viral replication upon initial exposure.