While the levels of total IgG and IgA antibodies did not differ in PASC patients and controls, both IgG and IgA anti-endothelial cell antibodies (i.e., binding in ELISA plates coated with HPMEC lysates) were lower among cases compared to controls, but only met statistical significance for IgG (p-value = 0.02). This evidence concerns the gene CD79A and long COVID-19.