Parallel studies on collagen hydroxyproline and hydroxylysine in human skin biopsies.

Studies on hydroxyproline and hydroxylysine, the two amino acids characteristic of collagen and related glycoproteins, were undertaken on biopsies of pathologic and clinically normal human skin. No statistically significant differences between clinically normal skin of mamma, thorax, axilla, femur, hip and sacral area were found. A decreased collagen content was seen in chronic pemphigus (bullous pemphigoid), amyloidosis, scleromyxedema and the edge of a leg ulcer. Determination of both amino acids is considered necessary to characterize alterations of collagen.