The anti-spike IgG antibodies produced by PAD patients in our study were functional in a surrogate virus neutralization test, as has also been reported previously (19), which is in contrast to the previous observation that memory B cells with high specificity against the receptor binding domain of the viral spike protein, cells known to produce most of the neutralizing antibodies against SARS-CoV-2, are undetectable in COVID-19 vaccinated CVID patients (18). This evidence concerns the gene CHMP5 and peripheral arterial disease.