BTK and idiopathic pulmonary fibrosis: We found that in HCs and IPF patients, phosphorylation of the signaling molecules within the BCR signalosome (BTK, SYK, and PLCγ2) strongly correlated with one another, in unstimulated conditions and following BCR stimulation in naïve B cells (Figure 2C,D), as well as in unstimulated memory B cells (Figure S3).