Incomplete Fibrin Formation And Highly Elevated Factor XIII Levels In Multiple Myeloma

In some patients suffering from multiple mye - loma a defect in fibrin formation has been suggested as one cause for bleeding tendency. However nothing is known about the commoness of this disorder or about the correlation to factor XIII activity.

As pointed out in this investigation the defect in fibrin formation, as proven in SDS-PAA electrophoresis, is due to a lack of α- chain polymerization in 5/11 patients with IgG - myeloma and 2/5 with IgM paraproteinemia. No disturbed fibrin formation could be observed in IgA myeloma (n=6). Factor XIII concentration of subunit A and to a smaller extent of subunit S (Laurell technique) were highly elevated in all cases with regular fibrin formation. Comparable values were obtained measuring the transamidase activity as incorporation of C 14 labelled putrescin into casein. Levels up to 600 % of normals could be evaluated. In contrast all patients with a lack of α- chain polymerization had a factor XIII activity within the normal range. Addition of factor XIII concentrate to plasma with defective fibrin formation led in 5 out of 7 cases to a partial crosslinking of α - monomers. A complete α- chain polymerization could not be achieved, even when high concentrations of factor XIII were used. We conclude that in some cases paraproteins can inhibit the factor XIII activity and prevent its action on fibrin. Patients, who are able to produce factor XIII, especially the active part subunit A in excess, can achieve a regular fibrin formation. Treatment with factor XIII in case of bleeding should be taken into consideration.