CD19 and autoimmune disease: The New Zealand (black×white) F1 hybrid mouse (NZB/W) develops spontaneous autoimmune disease by 12 weeks of age, which shares many characteristics with human SLE, such as the production of high-affinity anti-dsDNA IgG antibodies, glomerulonephritis and female sex bias.19–21 We used MIFC to quantify the number of LC3+ autophagosomes in CD19+ B cells in 13-week-old female NZB/W mice compared with C57BL/6 (B6) controls of similar age and sex.