Moreover, we found significant increases in spindle-shaped cardiac fibroblasts expressing both αSMA and CD4 in the fibrotic regions compared to the nonfibrotic regions of preserved autopsy RV tissue in humans with a clinical diagnosis of RV hypertrophy and dilation, compared to RVs from those without an autopsy diagnosis of PAH (Fig. 2b). The gene discussed is ACTA1; the disease is pulmonary arterial hypertension.