A skin biopsy from an rhSCF-injected test site (obtained 1 hour 40 minutes after the SC injection of 25 μg/kg of rhSCF ) from patient no. 3, who had received a single dose of rhSCF (day 1 of dosing), shows extensive DAO-gold-labeled fibrin (A) that is not seen if the section was digested with DAO before staining with DAO-gold (B). Original magnifications: (A) ×56,000; and (B) ×52,000.