GZMB and asthma: One of the proposed mechanisms which may be responsible for this phenomenon is upregulation in the expression of GR-β (Glucocorticoid receptor-β), which has previously been reported in steroid-insensitive subjects with severe asthma.[16] Christodoulopoulos and colleagues in our laboratory have characterized the expression of GR-β within the peripheral airways in cases of severe fatal asthma.