| Lymphocyte subset | Controls Mean (SD) | IPAH Mean (SD) | IPAH + BMPR2 Mean (SD) | CTEPH Mean (SD) |
| CD3+ | 73.8 (5.4) | 75.3 (6.2) | 76.7 (4.7) | 71.3 (11.9) |
| CD3+CD4+ | 49.6 (5.7) | 47.0 (6.3) | 50.9 (4.3) | 50.8 (8.7) |
| CD3+CD8+ | 22.1 (5.1) | 25.2 (5.3) | 23.5 (5.5) | 19.0 (7.8) |
| CD4+CD25+ | 17.8 (14.3) | 32.5 (24.4) | 32.1 (11.6) | 20.9 (7.5) |
| CD4+CD25+CD127− | 5.2 (1.5) | 6.5 (2.3) | 7.9 (2.5)* | 4.4 (1.8) |
| CD56+ | 8.2 (3.4) | 8.7 (4.0) | 7.0 (3.1) | 12.8 (8.1) |
| CD19+ | 15.8 (4.3) | 12.0 (3.6)* | 12.3 (1.1) | 12.2 (6.2) |
*p<0.05, compared with healthy controls. BMPR2, bone morphogenetic protein receptor-2; CTEPH, chronic thromboembolic pulmonary hypertension; IPAH, idiopathic pulmonary arterial hypertension.