SPINK4 and bronchiolitis obliterans syndrome: Applying a threshold set at the tenth centile to include 90% of cells in which at least one transcript was detected from each gene of interest (to reduce biological noise), we found that MUC2 RNA co-expressed with intelectin 1 (ITLN1) and Kazal type 4 serine peptidase inhibitor (SPINK4) in 61% of goblet cells from duodenum, gastric and BO samples (Fig. 4a–b).