CD19 and autoimmune disease: Similarly, transcriptome analysis of CD19+ B cells isolated from individuals with systemic lupus erythematosus revealed increased TBX21 expression compared to CD19+ B cells of healthy controls.[31] Importantly, HIV and malaria-associated atypical MBCs exhibit markedly reduced cytokine and antibody production capacity [4, 5, 32], whereas T-bet+ CD19+ B cells in individuals with autoimmune diseases can produce proinflammatory cytokines and autoreactive antibodies [33–35].