CD79A and systemic lupus erythematosus: IgA-specific responses to RBD and S1 were impaired in SLE patients after 2 and 3+ doses as shown by reduced IgA median titers (IgA titre median after two doses: RBD HC = 527.5 vs SLE = 424.1; S1 HC = 846.5 vs SLE = 0; IgA titre median after 3+ doses: RBD HC = 1145 vs SLE = 437.1; S1 HC = 1613 vs SLE = 999.7) (Fig. 1B, Supplementary Fig. 1B).