MBL2 and systemic sclerosis: Regarding PAH, we observed significantly higher median MBL levels in SSc patients with World Health Organization (WHO) functional class III/IV compared to I/II (2.39 (1.13 to 3.12) vs. 0.81 (0.19 to 2.24), P = 0.02) in accordance with a higher frequency of MBL2 high-producing genotypes (15 (75%) vs. 33 (47%), P = 0.03) in the same group.