Since PKR is a major mediator of inflammatory responses, is activated by IFN-γ and implicated in the onset and progression of arthritis, we hypothesised that the degenerative effects of IFN-γ are mediated via PKR signalling in osteoblasts and chondrocytes and that inflammation in early PTOA is associated with PKR activation. This evidence concerns the gene EIF2AK2 and Arthritis.