RESISTANCE TO ACTIVATED PROTEIN "C" AMONG EGYPTIAN PATIENTS WITH THROMBOEMBOLIC DISEASES

Abstract

Venous thromboembolism is an important health problem, annually affecting 1/1 000 individual as well as being the most common cause of death associated with major orthopedic surgery; namely, pulmonary embolism (Bertina eta/., 1988). Untill recently, the major inherited risk factors for venous thromboembolism were deficiencies of PC, PS and ATIII (Tabenero et al.. 1991). A progress has been made in 1993 when Dahl back and his colleagues reported the importance of activated protein C resistance APCR as a pathogeneic risk factor for thrombosis. APCR phenotype is associated with the factor V Leiden in more than 90% of cases, the molecular defects in the remaining 1 0% are yet unknown (Zoller et al., 1994). Moreover, Some physiological and pathological conditions were recently reported to be associated with an "acquired" APCR not caused by the Leiden mutation, such as inflammatory diseases, pregnancy. use of oral contraceptive pills (OCP) and menopause (Mann et al., 1988; Kluft et al.. 1999 and Marcucci et al., 1999). The co-existence of hereditary and acquired APCR has been suggested to explain the severity of thrombosis in a patient with familial antiphospholipid syndrome with factor V Leiden mutation (Brenner et al., 1996).