In SSc patients with PAH, we observed significantly higher median levels of β2-microglobulin (3.15 [2.76;3.49] vs. 2.46 [2.14;3.15] mg/L, p=0.02), sBCMA (36699 [32360;45190] vs. 32,068 [27656;35352] pg/mL, p=0.03), sCD23 (4609 [3469;7628] vs. 3094 [2554;4200] pg/mL, p=0.04), and sCD27 (8859 [6889;10667] vs. 6282 [5825;7645], p=0.05), and lower median levels of IgG (8.40 [7.10;10.40] vs. 10.45 [9.10;11.80] g/L, p=0.02), compared to those without PAH (Table 5; Figure 3). This evidence concerns the gene HLA-G and pulmonary arterial hypertension.