Yet, HD patients who developed an antibody response with IgG antibodies against the spike receptor-binding domain (RBD) of SARS-CoV-2 above 50 AU/ml following administration of the first vaccine dose, had at all times higher levels of CD19+ B cell counts in comparison to HD patients who failed to generate an antibody response at this time point. The gene discussed is CD19; the disease is Huntington disease.