Meanwhile, Ryu et al. [42] showed an increase in Tγδ cells and an increase in T Υδ lymphocyte expansion in the lungs of aged mice as well as a reduced Tγδ lymphocyte activation state after application of KD to mCoV-A59-infected male mice reproducing the clinical features of COVID-19 for 5 days prior to infection. The gene discussed is ABCA1; the disease is infection.