Based upon the premise that AAT neutralization of CELA1 plays a key role in the pathogenesis of emphysema in AAT-deficiency, we sought to test whether Cela1-neutralization using KF4 antibody could protect AAT-deficient mice from emphysema and compare its efficacy with AAT replacement therapy. This evidence concerns the gene CELA1 and hyperinsulinemic hypoglycemia, familial, 4.