ABSTRACT
To evaluate the Role of VWF factor VIII related Ag as a marker of activity in different childhood collagen vascular disorders, to study the relation between factor VIII and vasculitic manifestations in different collagen vascular disorders and to emphasise the relation between VWF and different clinicolaboratory manifestations in collagen diseases. Factor VIII Related Ag [VWF] is produced in megakaryocytes and endothelial cells, and present in plasma vascular subendothelium. It is stored in the alpha - granules of platelets and the Weibel-Palade body of the endothelial cells, it plays a pivotal role in hemostasis and pathological intravascular thrombosis: Patients with Henoch-Schonlein purpura [HSP], SLE, JRA and Juvenile dermatomyositis [JDM] had significantly high levels of VWF, indicating that high level may reflect the presence of vascular especially endothelial damage in patients with connective tissue diseases. The study included 65 patients attending the rheumatology clinic at Cairo University Pediatric Hospital aged from 4 to 10 years with different collagen disorders together with 20 age and sex matched controls. All patients and controls were subjected to full history taking, laboratory investingations including complete blood picture, ESR, CRP, ASOT, Renal function tests, C[3], C[4], 24 hour protein in urine, ANA and measuring serum levels VWF by ELISA. VWF was significantly higher in the four groups of patients with collagen vascular disease than in the control groups. The highest level of VWF was in HSP patients. The VWF showed higher levels in SLE patients with severe rash and renal involvement. It was also higher in JRA and dermatomyositis patients with vasculitic manifestations. The VWF levels were directly related to disease activity in both SLE and RA patients. The elevated level of VWF are most likely a reflection of the existence of outgoing vascular damage [Active vasculitis]. The VWF can be particularly helpful in assessing degree of systemic involvement as well as disease activity in patients with severe vasculitic form of JRA