PDGFRA and systemic sclerosis: One of the following may be postulated: (i) anti-PDGFRα autoantibodies are the result of the general break of tolerance towards self-antigens, which is a hallmark of SSc disease; (ii) more specifically, PDGFRα peptides recognized by autoantibodies may be the result of intracellular splicing processes caused by external triggers such as viral agents, e.g., CMV [45].