Fibronectin and factor VIII-related antigen in acute leukaemia

The glycoprotein fibronectin is, as well as by various other cells, also produced in leucocytes and is said to play an important role in malignant transformation of cells. Therefore, the behaviour of plasma fibronectin and of factor VIII R:AG was investigated in acute leukaemia in order to prove their significance as prognostic and therapeutic markers (method: electroimmunoassay). In patients with acute myeloid leukaemia (n = 29) and acute lymphoblastic leukaemia (n = 11) no significant changes in fibronectin concentration could be evaluated. Fibronectin levels declined significantly only during therapy with asparaginase in patients with acute lymphoblastic leukaemia, probably as a result of disturbed synthesis in the liver. Using crossed immunoelectrophoresis against fibronectin antiserum, one normal and one slower migrating antigen (FN:C) could be observed in nearly all plasma samples in patients with acute leukaemia. By means of in vitro tests with highly purified substances and intermediate gel electrophoresis it could be shown that FN:C represents fibronectin which has bound fibrinogen, probably crosslinked by activated factor XIII. Factor VIII R:AG was found to be greatly raised in patients with acute leukaemia--up to 1400% of the normal level. Increased levels correlated well with a worsening of the disease. The protein seems to be suitable for estimating the activity and prognosis of acute leukaemia.