RAB4B and chronic obstructive pulmonary disease: In blood, we validated PSMA4, EGLN2, and RAB4B for severe COPD (P = 3.79 × 10− 14, 1.34 × 10− 5, and 1.33 × 10− 4, respectively), and PSMA4 and LILRA3 for %LAA-950 (P = 3.37 × 10− 7 and 3.62 × 10− 5, respectively) by using GTEx-Blood as a validation for genes identified through whole blood transcriptome analysis (Table 3).