ACE2 and systemic lupus erythematosus: Systemic lupus erythematosus (SLE) patients are highly vulnerable to developing symptomatic SARS-CoV-2 infection, which is not a result of their compromised immune system, but rather upregulated ACE2 protein expression in the lung and its associated ACE2 gene hypomethylation along with significant demethylation of interferon genes [49].