BACKGROUND :
ADAMTS-13 is an enzyme that has function of cleaving von Willebrand factor multimer to monomer at normal plasma level. We have previously reported that the activity of ADAMTS-13 is decreased in thrombotic thrombocytopenic purpura (TTP) and advanced malignancy. In this study, we measured ADAMTS-13 activity in aging, pregnancy and other disease conditions for further understanding of its behavior in a variety of conditions.
METHODS :
The study included among 125 inpatients who were admitted at the Bundang Cha Hospital from July 2003 to February 2004 with liver cirrhosis, chronic renal failure, sepsis, disseminated intravascular coagulopathy (DIC), gastric cancer, colon cancer, and thrombotic microangiopathy, and 100 control subjects of different ages, in 20 normal full-term pregnant women and 20 postpartum women. The activity of ADAMTS-13 was assessed by multimer assay, based on electrophoresis. The presence of inhibitor was evaluated by mixing the plasma of patient with severely deficient ADAMTS-13 activity and normal plasma at the ratio of 1:1, 1:2, and 1:3.
RESULTS :
The median value, according to the age group from age 20~39 was recorded 97 % (range, 44~108%), age 40~59, 90% (range, 50~109%), and age group over 60 was 79% (range, 44~108%). the median value at third trimester was 76% (range, 6~103%), with postpartum state 84% (range, 74~100%), however, there was no significant difference compared with the healthy adult group. The median value for each categories of disease were 81% (range, 27~94%) for liver cirrhosis (P=0.0049), 61% (range, 25~110%) for chronic renal failure (P=0.0030), 80% (range, 32~111%) for DIC (P=0.0449) and 12% (range, 2~29%) for thrombotic microangiopathy (P<0.0001), respectively, compared to normal. In sepsis, gastric cancer and colon cancer, there was no significant change. In addition, the result showed positive for inhibitor assay among 3 patients out of 5 cancer patients, with severe deficiency of ADAMTS-13 activity.
CONCLUSION :
There was a decrease in the ADAMTS-13 activity among patients with liver cirrhosis, chronic renal failure, DIC and thrombotic microangiopathy compared with healthy control and inhibitors against ADAMTS-13 was detected in some malignant patients.

Keywords: ADAMTS-13, Age, Pregnancy, Disease