While one study measured SARS-CoV-2 spike protein-specific IgG titers in the serum of n = 4 MS patients prior to and after the initiation of ocrelizumab therapy (28), the second study assessed specific IgG titers in the serum as well as the spike antigen-specific CD4+ and CD8+ T cell responses in n = 7 patients (50). Here, CD8A is linked to myeloid sarcoma.