CCL21 and epidermolysis bullosa: In a study of EB in adults and children, it was found that serum CXCL12 and HMGB1 levels were significantly increased while CCL21 levels were decreased; moreover, immunofluorescence confirmed that CCL21, CCL27, HMGB1, and CXCL12 were more extensively expressed in the tissues of EB patients than in control tissues, indicating that fluctuations in chemokine levels may promote the wound healing process in a coordinated manner.197