PHGDH and asthma: KEGG results showed that the ‘allograft rejection’ pathway was enriched in the groups with low-expression of CNTN4, FILIP1, PHGDH, and TFPI2. In contrast, ‘alpha linolenic acid metabolism’ and ‘asthma’ pathway were associated with high-expression groups (Figures 7D–G) (Supplementary Table S19).