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BackgroundMost immune reactions related to transfusion and transplantation are caused by IgM ABO antibodies. However, IgG also plays an important role in these reactions. Therefore, a method to measure antibodies, including IgG, is necessary. We investigated ABO antibody titers of healthy individuals using a column agglutination technique (CAT) with or without dithiothreitol (DTT) and compared them with titers obtained using a conventional tube method.MethodsAmong healthy adults who underwent a medical examination, 180 individuals (60 with blood group A, 60 with group B, and 60 with group O) were selected. Antibody titrations were performed using the immediate spin (IS) tube, anti-human globulin (AHG) tube, and CAT with or without DTT methods.ResultsHigher median values of anti-B and anti-A titers in groups A and B individuals, respectively, were obtained using the IS method than using the AHG method. Higher values for group O individuals were obtained using the AHG method. Higher median titers of anti-B and anti-A in group O individuals were obtained using CAT without DTT than using the AHG method. Median titers of anti-B and anti-A in all blood groups were higher in CAT without DTT than in CAT with DTT, especially for group O individuals.ConclusionsWe recommend CAT with and without DTT for titration of anti-A and anti-B, especially in group O individuals, to provide more sensitive results that include IgG data. Adjustment of insurance coverage of fees associated with antibody titration might be necessary, considering the actual cost of reagents and personnel.

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We report a novel fibrinogen variant (fibrinogen Seoul II), which has a heterozygous point mutation from CAA to CCA leading to A␣Gln328Pro. The mutation site is among several glutamine residues that serve as ␣-chain cross-linking acceptor sites. Fibrinogen Seoul II was found in a 51-year-old male patient and his family in Seoul, Korea. The patient was diagnosed with myocardial infarction at age 43. Eight years later he was admitted to the emergency room due to recurrence of the disease, where he expired under treatment with tissue plasminogen activator (t-PA). Fibrin polymerization curves, made using purified fibrinogen from the patient's relatives, showed a decreased final turbidity, suggesting Seoul II fibrin clots are composed of thinner fibers. This supposition was verified using scanning electron microscopy. Alpha-polymer formation by the mutant fibrinogen upon thrombin treatment in the presence of factor XIII and calcium was distinctly impaired. This result confirms that the residue A␣328 plays a pivotal role in ␣ IntroductionFibrinogen, one of the critical plasma proteins, is a 340-kDa glycoprotein 1 synthesized in the liver 2,3 and has essential roles in both blood coagulation and platelet aggregation. 4 Fibrinogen is a dimer consisting of 2 identical pairs of A␣, B␤, and ␥ chains intertwined to form a trinodular molecule with 2 terminal D regions and a central E region. 5,6 The D region includes the carboxyl termini of the B␤ and ␥ chains, while that of the A␣ chain goes beyond the D region to form the ␣C domain, which is composed of residues A␣220-610 7 and normally interacts with the central E region.In the process of blood coagulation, thrombin cleaves fibrinopeptides A and B from A␣ and B␤ chains to form a fibrin monomer, exposing the GPR and GHRP sequences, respectively. Subsequently, protofibrils in a half-staggered array are formed, and the release of ␣C domains from the central E region is facilitated, allowing lateral aggregations through intermolecular associations between ␣C domains. 8,9 The final phase of fibrin clot formation involves the covalent modification of fibrin molecules by factor XIIIa. The factor XIIIa-mediated cross-linking process, where ␣-␣ cross-linking follows ␥-␥ cross-linking, contributes to stabilization of the fibrin clot and resistance to thrombolytic agents. 10,11 Until now, a variety of mutations in each of the fibrinogen chain genes have been reported in more than 350 families all over the world, with A␣-chain mutation as the most common form. 12 Those mutations usually have been associated with dysfibrinogenemia or hypofibrinogenemia, both of which feature decreased levels of plasma fibrinogen activity. Each A␣-chain has at least 2 glutamine acceptor sites located at amino acid residues 328 and 366 and 5 potential lysine donor sites between residues 518 and 584. 13 A␣ glutamine 328 is among several glutamine residues that serve as ␣-chain cross-linking acceptor sites, 10 for which only one fibrinogen variant has been described: compound heterozygotes characterized ...