An in vitro experiment in a larger study performed by Karsak et al. investigating the impact of the endocannabinoid system on allergic contact dermatitis (ACD) revealed that HaCaT keratinocytes with contact hypersensitivity conditions induced via polyinosinic:polycytidylic acid express an upregulation of CB1 and a downregulation of CB2 receptors [167]. Here, CNR1 is linked to granular corneal dystrophy type II.