CD4 and rheumatoid arthritis: In the RA cohort, frequencies of senescent CD4+CD28− and CD8+CD28− T-cells correlated significantly with BMD of the lumbar spine (CD4: corrcoeff = −0.361, p = 0.001, Figure 1C; CD8: corrcoeff = −0.248, p = 0.016), the hip (CD4: corrcoeff = −0.310, p = 0.003, Figure 1D; CD8: corrcoeff = −0.204, p = 0.045), and the femoral neck (CD4: corrcoeff = −0.275, p = 0.009; CD8: corrcoeff = −0.175, p = 0.088).