They also spontaneously express higher RNA levels for transcription factors involved in the secretion of autoimmune antibodies (tbx21, prdm1, XBP1), suggesting that DN B cells from obese individuals are already pre-activated, a status leading to spontaneous secretion of autoimmune antibodies, as shown in autoimmune diseases (53), and in the obese adipose tissue at least for some specificities (33, 41). This evidence concerns the gene XBP1 and autoimmune disease.