Noteworthy differences emerged in the expression levels of specific genes: Naïve B of HLA-B27- JIA showed elevated levels of HLA-DMB, HLA-DOB, and B2M, whereas Naïve B of HLA-B27+ JIA displayed increased expression of HLA-DPB1, HLA-DQA2, and HLA-DQB1 (Figure 5G). Here, B2M is linked to juvenile idiopathic arthritis.