CD4 and dry eye syndrome: In animals, we have reported that subconjunctival injection of HC-HA/PTX3 down-regulates activation of CD4+ Th1 cells to prolong the survival of murine corneal allografts30 and reduces infiltration of bone marrow-derived fibrocytes and immune cells to the lacrimal glands and conjunctiva to avert dry eye in chronic graft-versus-host disease (cGVHD) (Scientific Reports 7, Article number: 42195 (2017) doi:10.1038/srep42195).