TRIM21 and pulmonary arterial hypertension: The anti-Scl-70, anti-U3RNP, anti-Th/To, Bicaudal D homolog 2 (BCID2), Th/To (Rpp25/Rpp38), Ro52, eIF2B, anti-U11/U12 autoantibodies, as well as anti-Pm/Scl highly refer to interstitial pulmonary disease (ILD); however, pulmonary arterial hypertension (PAH) appears often in the presence of anti-centromere, anti-U3RNP, anti-Th/To positivity [51–54].