Studies on Fibrinogen Fractions Isolated from Human Plasma by Precipitation with Cold Ether

Abstract

During clinical trials of a human antihaemophilic globulin concentrate (HAHG) prepared from very fresh plasma by the method of Kekwick and Wolf (1957), it was observed (Maycock, Evans, Vallet, Combridge, Wolf, MacGibbon, French, Wallett, Dacie, Biggs, Handley and Macfarlane, 1963) that the transfusion of this material into haemophiliacs was sometimes followed by reactions similar to those observed by Fox, Goldsmith, Kidd and Lewis (1961) after the intravenous injection of purified bradykinin. A chemically similar fraction (ETF), prepared from aged plasma, has been used for many years for the treatment of hypofibrino‐genaemia without any reported reactions. The reactions described by Maycock et al. (1963) were sufficiently frequent and severe to warrant an investigation of the kininogenic properties of HAHG and, for comparative purposes, of ETF. For reasons not understood, but clearly associated with the adoption of a modification of the original technique (Kekwick and Walton, 1965), reactions occurring during the transfusion of recently prepared batches of HAHG into haemophiliacs are now no greater in number and severity than those occurring during the transfusion of fresh plasma. Human plasma contains prokininogenases, the precursors of enzymes which hydrolyse protein substrates (kininogens, kallidinogens) to produce kinins, polypeptides which cause vasodilation and plain muscle constriction (Lewis, 1960). Activation of two of these proenzymes, kallikrein and plasminogen (profibrinolysin), could lead to the production of kinin in HAHG either during preparation, or during transfusion, and might cause the observed reactions.

Studies on Fibrinogen Fractions Isolated from Human Plasma by Precipitation with Cold Ether

“…Several batches were therefore incubated with the same fresh plasma in the proportion of 10 : I (Table I). This experiment was performed by the authors of Mackay et al (1965), and is included here by their kind permission. In most other tests it was not possible to incubate the same fresh plasma with all HAHG and ETF batches, and their effects were therefore not strictly comparable.…”

“…Fig. I in Mackay et al, 1965). The fractions also contain a factor capable of activating the kallikreinogen in the patient's plasma.…”

“…I in Mackay et al, 1965). The fractions also contain a factor capable of activating the kallikreinogen in the patient's plasma.The nature of the enzymic contaminant in HAHG and ETF, which hydrolysed p-tosyl-Larginine methyl ester (TAMe) even when the plasminogen in the two fractions had not bccn activated (Mackay et al, 1965), was also investigated in the presciit study.…”

“…The nature of the enzymic contaminant in HAHG and ETF, which hydrolysed p-tosyl-Larginine methyl ester (TAMe) even when the plasminogen in the two fractions had not bccn activated (Mackay et al, 1965), was also investigated in the presciit study.…”

“…Since HAHG and ETF do not contain plasmin (Mackay et al, 1965), their direct kininforming activity may be attributed to plasma kallikrein. The potcncy of the two fibrinogen fractions was therefore compared with that of purified human plasma kallikrein (Webster and Pierce, 1961).…”