TREC content of naive CD4⁺ T cells correlates negatively with CRP and CRP correlates positively with circulating naive and atypical CD4 ^± T cells.

(A) Cross-sectional study. TREC content of naive CD4⁺ T cells was plotted against CRP for RA patients, illustrating a negative correlation (r = −0.750,P < .0001). (B) Longitudinal study. Longitudinal data from a patient with RA (24-year-old woman) with fluctuating disease severity. CRP (▪) and TREC content of naive (CD45RB^bright CD45RA⁺ CD62L⁺) CD4⁺ T cells (⋄) are negatively correlated, whereas CRP and atypical (CD45RB^bright CD45RA⁺CD62L⁻) cell counts (▵) are positively correlated. (C) Cross-sectional study. The proportion of circulating CD4⁺ T-cells of naive (♦) and atypical (⋄) phenotype was determined as described in Figure 1 and plotted against CRP. There was a positive correlation between CRP and frequency of atypical cells (r = +0.537, P < .0001) and a weaker correlation with the frequency of naive cells (r = +0.366,P = .017).