When analyzing the spatial distribution of the two signals, we noticed that in donors they were tightly co-expressed (Figure 4D upper panels), but in IPF there was a heterogeneous distribution of the areas of mature and proSP-B co-localization (particularly in non-affected areas, Figure 4D panels in rows 2 and 4) and areas where the mSP-B was low or absent in cells that expressed the pro forms (Figure 4D—panels in row 3). This evidence concerns the gene MSMB and idiopathic pulmonary fibrosis.