CD34 and systemic sclerosis: In order to evaluate the contribution of each variable on CD34+ cell number, we carried out a linear regression analysis among SSc patients only (we tested the dependence from endocan, vitamin D levels, CRP, fibrinogen, SUA, sPAP); dependence analysis suggested that endocan (β = −0.514; p < 0.005), fibrinogen levels (β = −0.667; p < 0.001) and sPAP (β = −0.498; p = 0.006) are negatively associated with CD34+ cell number.