Fibronectin In Commercial Coagulation Factor Concentrates And Response Of Fibronectin Plasma Levels To Infusions

Abstract

Fibronectin (FN) was assayed via a commercial mono-specific antiserum (Cappell Labs Inc.) using a Laurel immuno- electrophoretic assay with a pool of 10 normal plasmas as control. This control pool was arbitrarily given the FN concentration of 100% containing 300 μg FN/ml plasma. FN was measured in various lots of different commercial factor concentrates and cryoprecipitate. The concentration of FN varied widely among 3 different commercially available FVIII concentrates. One product showed a mean level of 2,376% (6 lots), a second 415% (4 lots) and a third 903% (2 lots). The average FN level of 3 cryoprecipitate preparations was 576%. FN was not present in 3 lots of one commercial FIX concentrate. FN was assayed in the plasma of 12 patients with hemophilia before and immediately after factor concentrate/cryoprecipitate infusion for therapeutic purposes. The response of the plasma FN level to the infusion was assessed by determining the total FN infused (mg), the observed rise in plasma (%) and the absolute FN amount producing a 1% rise in plasma level. The quantity of FN infused (a function of volume of infusate and concentration of FN) varied widely from 1.19 mg to 17.0 mg total. The observed rise depended inter alia on absolute FN infused and body weight. This ranged between 0 and 139%. Cryoprecipitate produced the greatest rise of plasma FN level per unit weight of FN infused. The commercial concentrates showed a wide spectrum of plasma FN responses in most cases requiring greater absolute FN infusion doses than cryoprecipitate for each 1% of increase in plasma level. These results indicate that FN is a major contaminant of some commercial Factor VIII concentrates. It is possible that FN is denatured by the concentration process resulting in very rapid removal of infused FN from the circulation.