HLA-B and pulmonary arterial hypertension: The study subjects (lcSSc with PAH and without PAH), as well as healthy controls (HC) were stratified for the presence of HLA-B*35 allele (18 % of the HCs and 27 % of the lcSSc were B35-positive, of those 27 % of PAH and 26 % of NoPAH patients were B35-positive).