Serum elastase inhibitor levels in Ehlers-Danlos syndrome.

Prior studies from this laboratory of the elastinelastase-serum elastase inhibitor system disclosed, among other findings, a consistent 2to 3-fold increase in the inhibitor in late pregnancy (Schneider, Walford, and Dignam, 1960). Other disease states, including arteriosclerosis, lupus erythematosus, dermatomyositis, severe liver disease, and nephrotic syndrome, showed mild but inconstant changes in inhibitor levels (Walford and Schneider, 1959). The regular elevation of elastase inhibitor in late pregnancy is of interest in view of the increased incidence of dissecting aortic aneurysm, which is primarily an elastic tissue disease, in pregnancy (Mandel, Evans, and Walford, 1954). Elastase inhibitor levels might thus reflect changes in the status of elastin or elastase in the body. The investigation reported here was stimulated by the observation (Hall, Keech, Reed, Saxl, Tunbridge, and Wood, 1955) that the level of elastase inhibitor in a patient with Ehlers-Danlos syndrome was 50 to 100 times higher than normal. Such an elevation would be not only of theoretical and diagnostic importance for this disease state, but might afford a source wherefrom pure inhibitor could be isolated by appropriate techniques. Accordingly we have studied a group of seven patients with classical Ehlers-Danlos syndrome or certain features thereof. In addition to measurement of inhibition of elastolysis by elastase inhibitor, inhibition of casein proteolysis by the enzyme was determined.