Birger Blombäck (May 7, 1926 - October 2, 2008).

Birger Blomback was born and raised on a small farm in Kalix-Bredvik in the very north of Sweden. He began his medical studies at the Karolinska Institute in 1949. He married his course mate Meta (Margareta) and together they joined the research group of Professor Erik Jorpes in 1951. Birger’s dissertation, published in 1958, included seven manuscripts that all centered on fibrinogen. The first, which described a new method to purify fibrinogen from human and bovine plasma, set the foundation not only for his dissertation but also for the growing field of fibrinogen research. Birger’s contributions to our knowledge and understanding of fibrinogen and its transformation to a fibrin gel are multiple, fundamental and wide-reaching. He has provided several reviews for the field including, most recently, a historical perspective entitled ‘Travels with fibrinogen’ [Blomback B. Journal of Thrombosis and Haemostasis 2006; 4: 1653–1660]. This delightful, autobiographical report summarizes his work and its part in the history of fibrinogen. A few specific experiments illustrate Birger’s extensive influence on the field. Over the years he worked with many inspired, dedicated and highly skilled scientists. In collaboration with Ikuo Yamashina he characterized, as a part of his dissertation, the N-terminal amino acids in fibrinogen and fibrin. These studies identified the specific amino acids, demonstrated that fibrinogen was likely a dimer with two copies of three chains, and showed that fibrin differed from fibrinogen in the N-terminal residues of four of the six chains [Blomback B, Yamashina I. Ark Kemi 1958; 12: 299–319]. In 1961–1962, Birger and Meta together with Pehr Edman, then at St. Vincent’s School of Medical Research in Melbourne, determined the complete fibrinopeptide sequences utilizing for the very first time the procedure designed by Edman [Blomback B, Blomback M, Edman P, Hessel B. Biochim Biophys Acta 1966; 115: 371–396]. In 1967. Eberhard Mammen from Wayne State University in Michigan contacted Birger and Meta to ask their assistance in analyzing a patient whose plasma had normal levels of fibrinogen, but did not form a clot. Using trypsin digests and two-dimensional electrophoresis-chromatography on thin layer cellulose plates, they identified the defect, a single substitution of arginine to serine at position Aα19 [Blomback M, Blomback B, Mammen EF, Prasad AS. Nature 1968; 218: 134–137]. This was the first dysfibrinogen and the second, after sickle-cell hemoglobin, protein variant defined by a missense mutation. As fibrinopeptide release from this variant was normal, these experiments clearly demonstrated the critical role of this region in formation of a fibrin gel. Subsequent studies with this variant protein led Birger and his coworkers to propose a two-step model for the transition of fibrinogen to fibrin [Blomback B, Hessel B, Hogg D, Therkildsen L. Nature 1978; 275: 501–505] Birger found the architecture of the fibrin clot is controlled by the initial kinetics of the reactions. This was true for reactions with pure proteins or with plasma [Blomback B, Carlsson K, Fatah K, Hessel B, Procyk R. Thromb Res 1994; 75: 521–538]. These findings led us to understand that the clot architecture in vivo, and thus clot stability and endurance, is controlled by the rate of thrombin generation. Consequently, many clinical papers have examined the fibrin network structure and have found significant differences, showing for instance a tighter network in patients with heart infarcts and stroke. Birger was a strong advocate for coagulation research. Along with Alfred Copley, he started the journal Thrombosis Research in 1972. A quote from their foreword to the first volume presents his commitment and enthusiasm for the research and the individuals who dedicate themselves to it. ‘As we launch Thrombosis Research, we hope that the students of thrombotic and allied conditions will have their forum in this journal. To them we extend a cordial invitation to make use of Thrombosis Research, to nurture and cherish it, and to regard it as their own’. Birger was also an active participant in the International Society for Thrombosis and Haemostasis, serving as President for the IX Congress held in Stockholm in 1983. Meta and Birger remained lifelong collaborators publishing more than 40 manuscripts together. They received The Hilda and Alfred Eriksson Prize from The Royal Swedish Academy of Sciences in 2001 and the Erik K. Fernstrom’s Nordic Prize from the Medical Faculty in Lund in 2002. These prizes acknowledged their important contributions to replacement therapy for treating Hemophilia A and von Willebrand disease. They used the first fraction (fraction I–0) from the new fibrinogen purification protocol to treat a girl with severe ‘pseudohemophilia’, later named von Willebrand disease. This treatment corrected the patient’s prolonged bleeding time, allowing for successful surgery. Subsequent experiments and clinical observations showed this fraction contained both factor VIII and von Willebrand factor. Birger described the von Willebrand factor story in a recently published book chapter. [Blomback B. A journey with bleeding time factor. Personal Recollections Ed. G. Semenza, Elsevier B.V, Compr Biochem 2007; 45: 209–255]. These prizes also recognized the Blomback’s contributions to the development of synthetic chromogenic peptide substrates, linked to p-nitroanilide, first for thrombin. Birger is survived by his second wife Ching Chiang, his sons Henning Blomback and Niklas Bark and family. We convey our sympathies to them. The fibrinogen research community has lost an important and inspiring leader; we will miss him.