CFHR2 and pulmonary arterial hypertension: The plasma CFHR2 level in ASD-PAH patients (70.92 ± 8.267 ng/ml, n = 11; P = 0.000 by ANOVA compared with control group) and ASD patients (72.48 ± 8.991 ng/ml, n = 11; P = 0.000 by ANOVA compared with control group) were significantly lower than that in normal controls (189.1 ± 24.01 ng/ml, n = 16; Fig. 3), although there was no significant difference between ASD-PAH and ASD patients.