Systemic lupus erythematosus (SLE) is the most common connective tissue diseases associated with pulmonary arterial hypertension (PAH) in China. 4% of Lupus patients suffer from PAH which is one of the leading causes of death for SLE. The pathologic changes and underline mechanism lead to the pulmonary vascular remodelling in SLE patients remains to be identified.
SNPs selected from TGF-β pathway genes (BMPR2, ALK1, Endoglin and SMAD9) were detected in SLE-PAH patients from Peking Union Medical College Hospital registry to explore genetic susceptibility for PAH in SLE. The level of autoantibodies of BMP receptors in serum from patients with SLE-PAH and controls (SLE patients without PAH and healthy volunteers) were detected via enzyme linked immunosorbent assay assays. The inflammatory factors were examined by immunoblotting in pulmonary arterial endothelial cells (PAECs) stimulated with bacteria toxin. Finally, we analysed the specific immune cell(s) involved in SLE-PAH by a comparation of cellular components in peripheral blood collected from patients prior to the first administration and after treatment of glucocorticoids and vasodilators.
We identified that the autoantibodies of BMP receptors were higher in the serum of SLE-PAH patients compared with controls. Furthermore, the expression level of certain inflammatory factors in PAECs was affected by bacteria toxin. The number of granulocytes was elevated in the SLE-PAH patients after treatment, which indicated that granulocytes may participate in the develop of PAH in SLE patients.
Our results revealed mechanism of PAH onset in SLE, implied certain pro-inflammatory factors were involved in the pathogenesis of SLE-PAH.