Moreover, Spearman correlation tests were used to examine whether there was a relation between development of PAH and the patients’ demographic parameters, the presence or absence of autoantibodies (anti-centromere antibody, anti-DNA-topo-isomerase I and anti-RNA-polymerase III), CRP levels, the level of miRNAs in the plasma and the pulmonary function test results (DLCO, 6MW). This evidence concerns the gene CRP and pulmonary arterial hypertension.