Waldenström macroglobulinemia transforming from t (11;18) (q21;q21) -negative gastric MALT lymphoma after systemic dissemination.

AIM: We here describe the clinical course of a 70-year-old male patient with Waldenström macroglobulinemia (WM) putatively transformed from refractory mucosa-associated lymphoid tissue lymphoma (MALTL). METHODS: Immunological staining was performed on formalin-fixed, paraffin-embedded tissue sections, and M-protein and cryoglobulin were identified by immunofixation electrophoresis and the cold precipitation method. Chromosome translocation was analyzed by the G-banded karyotype, and API2/MALT1 fusion gene underwent fluorescent in situ hybridization. Multiplex polymerase chain reaction was performed to analyze the VH-JH or DH-JH rearrangements of the IGH gene. RESULTS: At diagnosis, the WM patient had monoclonal IgM with cryoglobulinemia and hyperviscosity syndrome. Eight years before developing WM, the patient experienced the onset of typical gastric MALT-L with H. pylori infection, but in spite of negative for chromosome translocation, t (11;18) and the successful eradication of H. pylori, the MALT-L relapsed repeatedly, and finally led to systemic metastasis. The lymphoma cells also infiltrated the large intestine and spleen. Immunoglobulin gene analyses of cellular clonality revealed that the same clone had been present in the stomach, bone marrow (BM) at the onset of MALT L, and in the BM at the diagnosis of WM. CONCLUSIONS: In this case, lymphoma developed as H. pylori-associated gastric MALT-L with negative for t (11;18), and might be transformed into MW during the systemic metastasis.

Heterozygous Bß-chain C-terminal 12 amino acid elongation variant, BßX462W (Kyoto VI), showed dysfibrinogenemia.

A heterozygous patient with dysfibrinogenemia with slight bleeding and no thrombotic complications was diagnosed with fibrinogen Kyoto VI (K-VI). To elucidate the genetic mutation(s) and characterize the variant protein, we performed the following experiments and compared with identical and similar variants that have already been reported. The proposita's PCR-amplified DNA was analyzed by sequencing and her purified plasma fibrinogen underwent SDS-PAGE followed by immunoblotting, fibrin polymerization, and scanning electron microscopic observation of fibrin clot and fibers. Sequence analyses showed that K-VI fibrinogen substituted W (TGG) for terminal codon (TAG), resulting in 12 amino acid elongation 462-473 (WSPIRRFLLFCM) in the Bß-chain. Protein analyses indicated that the presence of some albumin-binding variant fibrinogens and a dimeric molecule of variant fibrinogens reduced fibrin polymerization, with a thinner fiber and aberrant fibrin network. These results are almost the same as for the identical variant of Magdeburg, however, different from the similar variant of Osaka VI [12 amino acid elongation 462-473 (KSPIRRFLLFCM) in the Bß-chain] in the presence of variant forms and clot structure. We speculate the side-chain difference at 462 residues, W in K-VI, K in Osaka VI, and/or the difference in the presence of disulfide bridged forms of variant fibrinogens, led to the notable difference in the fibrin bundle network. Although a strong evolutional and structural association between Bß-chain and γ-chain molecules is established, the corresponding recombinant 15 residue elongation variants of the fibrinogen γ-chain showed reduced assembly and secretion.

[Role of fibrinogen Bbeta-chain D-region 454-458 residues for assembly and secretion of intact fibrinogen].

BACKGROUND: To examine the role of fibrinogen Bbeta-chain D region in the assembly and/or secretion of multichain protein, we synthesized eight variant fibrinogens with truncated Bbeta-chains in the C terminal region, terminating with 454, 455, 456 or 458 residues, and with substitution at Bbeta-455Arg by Lys, Ile, Ala or Asp in Chinese hamster ovary (CHO) cells. METHODS: A fibrinogen Bbeta-chain expression vector was altered and transfected into CHO cells that expressed normal human fibrinogen Aalpha- and gamma-chains. Expressed fibrinogens of cell lysates and culture media of the established cell lines were subjected to ELISA and immunoblot analysis. RESULTS: The CHO cells synthesized eight variant Bbeta-chains and assembled these into fibrinogen except for Bbeta-454 and Bbeta-455Asp. However, in the cell lysates, concentrations of these variant fibrinogens were lower than that in wild type cells. These assembled variant fibrinogens were secreted into the culture medium, and the levels in culture media were also lower than that in the medium of wild type cells. Significant differences in the mean ratios of fibrinogen concentration in medium to that in cell lysate were not observed between the variant type cells and the wild type cells. CONCLUSIONS: Residues of the Bbeta-chain D domain are essential for fibrinogen assembly, especially the Bbeta-455 residue was critical. The present study indicated that the structure of the fibrinogen Bbeta-chain C terminal D region is necessary for fibrinogen assembly, but not for secretion.

Factor H gene variants in Japanese: its relation to atypical hemolytic uremic syndrome.

Mutations and polymorphisms of factor H gene (FH1) are known to be closely involved in the development of atypical hemolytic uremic syndrome (aHUS). Several groups have identified disease risk mutations and polymorphisms of FH1 for the development of aHUS, and have investigated frequencies of aHUS in a number of ethnic groups. However, such studies on Japanese populations are limited. In the present study, we analyzed FH1 in Japanese aHUS patients and healthy volunteers, and examined whether those variants impacted on a tendency for the development of aHUS in Japanese populations. Similar to previous studies, we found that a high frequency of FH1 mutations, located in exon 23 of FH1, encodes short consensus repeat 20 in C-terminal end of factor H molecule in patients with aHUS (40%), but not in healthy volunteers. Interestingly, no significant differences in frequency of well-known disease risk polymorphisms for aHUS were observed between healthy volunteers and aHUS patients. Our results suggested that although FH1 mutations relates to the development of Japanese aHUS in accordance with other ethnic studies, other factor may be required for factor H polymorphism to be a risk factor of Japanese aHUS.

Analysis of plasmin generation and clot lysis of plasma fibrinogen purified from a heterozygous dysfibrinogenemia, BbetaGly15Cys (Hamamatsu II).

We found a heterozygous dysfibrinogenemia caused by the substitution of BbetaGly15Cys and designated it fibrinogen Hamamatsu II (H-II). Although the propositus suffered an infarction of the medulla oblongata, other thrombotic risk factors, paradoxical cerebral infarction, and arterial dissection were not found. To determine whether the delayed lysis of fibrin clots or not in the context of the BbetaGly15Cys substitution, we examined the clot lysis and plasmin generation of propositus' fibrinogen. Fibrinogen was purified from the propositus' and normal control plasma by immunoaffinity chromatography and was used for the following experiments: sodium dodecyl sulfate-polyacrylamide gel electrophoresis, fibrin polymerization, scanning electron microscopic observation of fibrin clot and fibers, clot lysis, and tissue-type plasminogen activator-mediated plasminogen activation. The H-II plasma fibrinogen showed the presence of albumin-binding variant forms, a dimeric molecule of variant fibrinogen, and impairment of lateral aggregation during fibrin polymerization. The H-II fibrin clot showed lower density of bundles and thinner diameters of fibers than in the normal fibrin clot. In the clot lysis experiments with overlaid plasmin, H-II fibrin showed a similar lysis period and lysis rate to the normal control. Moreover, plasmin generation from a mixture of thrombin, tissue-type plasminogen activator, plasminogen, and H-II fibrinogen also showed a similar rate to normal fibrinogen. Although the propositus suffered an infarction, the present study did not observe delayed clot lysis, that is, the clot was not resistant to plasmin degradation. Therefore, we did not clarify an association between the BbetaGly15Cys dysfibrinogenemia and arterial thrombosis.

[Functional analysis of heterozygous plasma dysfibrinogens derived from two families of gammaArg275Cys and three families of gammaArg275His, and haplotype analysis for these families].

We have identified five heterozygous dysfibrinogenemias, two families with variant fibrinogen gammaArg275Cys (CGC > TGC; Matsumoto III and Sendai) and three families with gammaArg275His (CGC > CAC; Otsu II, Iida, and Shizuoka), from PCR-amplified DNA fragments and direct sequence analysis. gammaArg275 is the most important residue in fibrinogen for the so-called "D-D interface" in protofibril elongation. We compared the functions of plasma fibrinogen purified from affected family members with gammaArg275Cys and gammaArg275His. Both fibrinogens showed markedly impaired thrombin-catalyzed fibrin polymerization in comparison with normal controls. The degree of impairment of gammaArg275Cys fibrinogen was greater than that of gammaArg275His. These results were consistent with the fibrinogen concentration ratio (thrombin time method/immunological method). That is, the ratio of gammaArg275Cys was significantly lower than that of gammaArg275His. Moreover, scanning electron microscopy indicated significantly thicker fibers in fibrin clots made from gammaArg275Cys than in those of normal controls or gammaArg275His, and abnormal bundles with tapered ends. Factor XIIIa-catalyzed cross-linking of the fibrinogen gamma-chain (in the absence of thrombin) showed a similar delay for gammaArg275Cys and gammaArg275His. We report markedly impaired fibrin polymerization of gammaArg275Cys compared to gammaArg275His, and speculate that the difference is due to the disulfide-linked Cys in gammaArg275Cys, as we have already demonstrated for plasma and recombinant mutant fibrinogens. These results also indicate that an amino acid substitution of gammaArg275 disrupts D:D interactions in fibrin fiber formation. Furthermore haplotype analysis for three families with gammaArg275His suggested that founder of Iida family might be different from that of Otsu II or Shizuoka family.

[Analysis of antibody reactivity for FDP D-dimer fragments by Western blotting].

We evaluated three test kits for fibrin degradation products (FDP) D-dimer. We found that six of 217 plasma sample values obtained by Nanopia test were markedly higher than the values obtained using the other two kits. The regression equation for 211 samples (excluding six) was y=0.64x+3.05 (y: Nanopia, x: LIAS AUTO) and the correlation coefficient was 0.915. Therefore, we classified these samples into three categories, namely correlated(y< 1.0x), incompatible (y= 1.0x-2.9x) and markedly incompatible (y> or =3.0x). Selected samples, eight correlated, four incompatible and four markedly incompatible, were analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis followed by Western blotting(WB). WB analysis using anti-fibrinogen antibody showed that both high molecular weight fragments of cross-linked fibrin (HMW-XDP) and DD/E fragments were present in the correlated samples, but there was less HMW-XDP than DD/E in the incompatible samples and mostly DD/E (HMW-XDP was significantly less than DD/E) in the markedly incompatible samples. These data suggest that plasma FDP samples that contain mostly DD/E and little HMW-XDP demonstrated markedly incompatible values using the three D-dimer test kits. These data was reflected by markedly elevated plasmin alpha2-plasmin inhibitor complex values in the incompatible and markedly incompatible samples. Unfortunately, we did not directly demonstrate these phenomena by WB analysis with two anti-D-dimer antibodies used Nanopia or LPIA reagent. In the near future, we expect that standardization of FDP D-dimer assay will be accomplished.

[Analysis of hypofibrinogenemias found on routine coagulation screening tests and identification of heterozygous dysfibrinogenemia or fibrinogen deficiency].

We analyzed the clinical factors resulting in hypofibrinogenemia, which is defined as less than 100mg/dl of plasma fibrinogen values determined by a procedure based on the Thrombin-time method. Within a 12-month period, we assayed 5,746 patients (19,309 plasmas) and found 113 patients (1.97%) with hypofibrinogenemia. We categorized these patients as having decreased synthesis of fibrinogen (less than 3.0g/dl of albumin, 140 IU/l of Cholinesterase, and/or 50% on Hepaplastin Test), increased consumption of fibrinogen (more than 10 microg/ml of FDP D-dimer), known side effect of L-asparaginase administration, or other causes. Details are follows: 1) decreased synthesis: 26 patients, suspected of decreased synthesis (albumin: 3.1-3.4 g/dl): 4 patients, 2) increased consumption: 15 patients, suspected of increased consumption (FDP D-dimer: 5.0-9.9 g/dl): 1 case, 3) decreased synthesis combined with increased consumption: 24 patients, suspected of decreased synthesis and/or suspected of increased consumption: 14 patients, 4) side-effect of L-asparaginase administration: 24 patients, 5) heterozygous dysfibrinogenemia: 1 patient, 6) heterozygous fibrinogen deficiency: 1 patient, suspected of heterozygous fibrinogen deficiency: 1 patient, 7) unidentified: 2 patients with West syndrome treated with a combination of ACTH and valproic acid. Three patients with dysfibrinogenemia or fibrinogen deficiency showed normal or slightly prolonged PT values and normal APTT values. These data and our previous reports suggest that heterozygous patients with dysfibrinogenemia or fibrinogen deficiency do not demonstrate markedly prolonged PT and APTT values, differing from patients with afibrinogenemia.

In vitro expression of beta-thalassaemia gene (IVS1-1G>C) reveals complete inactivation of the normal 5' splice site and alternative aberrant RNA splicing.

We previously reported a case of heterozygous beta-thalassaemia with IVS1-1G > C substitution in the beta-globin gene and a non-detectable level of mutant mRNA in the patient's reticulocytes. The purpose of this study was to determine whether the transcription and RNA splicing and processing of the mutant gene occurred. We analysed the expression of the mRNA encoded by the cloned mutant gene in COS-1 cells by reverse transcription-polymerase chain reaction followed by agarose gel electrophoresis and nucleotide sequencing. The G > C mutation completely inactivated the normal 5' splice site and resulted in the activation of two cryptic 5' splice sites, located 16 and 38 nt upstream of the normal site. The usage of these two cryptic sites accords with the findings of reports on IVS1-1G > A or IVS1-1G > C substitution of exon 1 of the beta-globin gene. Additional experiments that involved transfection of equal amounts of both normal and mutant vectors into COS-1 cells indicated the presence of mutant mRNAs. In conclusion, the beta-thalassaemia gene (IVS1-1G > C) was expressed in transfected cells, but showed aberrant RNA splicing. Further studies will be required to clarify the molecular mechanism that results in severe reduction in the mutant mRNA level in vivo.

A novel variant fibrinogen, deletion of Bbeta111Ser in coiled-coil region, affecting fibrin lateral aggregation.

BACKGROUND: Functional fibrinogen concentration of a male infant showed <0.50 g/l and we speculated this patient as a dysfibrinogenemia or hypofibrinogenemia. METHODS: We analyzed propositus and his parent by DNA sequencing and by thrombin-catalyzed fibrin polymerization for purified plasma fibrinogen. RESULTS: Although functional fibrinogen determinations based on Clauss method showed the marked discrepancy of values among 3 sets of reagent and analyzer, we found a novel heterozygous variant fibrinogen, Kyoto IV, caused by 3-bp deletion in Bbeta-chain gene corresponding to the deletion of 111Ser located in coiled-coil region. We suggested that the discrepancy of fibrinogen values among 3 assays was caused by the difference in NaCl concentration in reagents for determination and analyzed the polymerization under the conditions of various NaCl concentrations. Although under normal physiological conditions Kyoto IV fibrinogen augmented the polymerization as compared with normal control, in 0.21 mol/l NaCl Kyoto IV fibrinogen showed abruptly impaired polymerization curve compared with normal control. CONCLUSION: Variant fibrinogen, BbetaDelta111Ser, showed augmented lateral aggregation under normal physiological conditions and the residue located in coiled-coil region, Bbeta111Ser, plays an important role in the lateral aggregation.

Characterization of factor XII Tenri, a rare CRM-negative factor XII deficiency.

Factor XII Tenri (Y34C), a rare cross-reacting material (CRM)-negative factor XII deficiency, was identified in a 71-yr-old Japanese woman with angina pectoris. In the patient's plasma, factor XII activity and antigen levels were only 1.6% and 5.0%, respectively, of those seen in a normal subject. Immunoblot analysis showed that the secreted factor XII Tenri existed not only as a monomer (76 kDa), but also in complexes with apparent molecular weights of approximately 115, 140, 190, 215, and 225 kDa. After reduction with 2-mercaptoethanol, the factor XII Tenri contained in the complexes was completely converted to monomeric form on immunoblot patterns. It appeared that some of the secreted factor XII Tenri formed several types of disulfide-linked complexes, including a factor XII-alpha1-microglobulin complex, through a newly generated Cys residue. The monomeric form of factor XII Tenri, like normal factor XII, was degraded into 2 major fragments with molecular weights of approximately 45 kDa and 30 kDa following mixing with activated partial-thromboplastin-time measuring reagent (cephalin and ellagic acid), whereas the factor XII Tenri that formed the complexes was not. This indicates that the factor XII Tenri present in disulfide-linked complexes with other proteins (and itself) is not converted to active forms, suggesting that attached proteins obstruct or delay the activation of factor XII via an inhibition of its binding to a negatively charged surface in vitro.

Quantitative RT-PCR analysis demonstrates that synthesis of the recombinant fibrinogen is dependent on the transcription and synthesis of gamma-chain.

BACKGROUND: The purpose of this study was to examine the relationship between the production of secreted fibrinogen and the synthesis of gamma-chain mRNA. METHODS: We transfected a gamma-chain expression vector into Chinese hamster ovary cells already expressing both Aalpha- and Bbeta-chains of fibrinogen and measured fibrinogen output concentrations by ELISA. We quantified both gamma-chain and Bbeta-chain mRNA concentrations using the recently developed TaqMan fluorogenic detection system. RESULTS: The concentration of secreted fibrinogen into the media positively correlated with the amount of fibrinogen contained in the cell lysates. Additionally, quantitative mRNA assays revealed that the fibrinogen concentration in the cell lysates correlated well with the concentration of gamma-chain mRNA (r=0.7077, p<0.01) but not with the concentration of Bbeta-chain mRNA (r=0.0224, NS). CONCLUSIONS: These results demonstrate that the amount of recombinant fibrinogen produced in cells transfected with the gamma-chain vector, also expressing normal Aalpha- and Bbeta-chains, is dependent on the transcription of gamma-chain mRNA. Namely, in this recombinant expression system using a two-step transfection procedure, gamma-chain synthesis is the rate-limiting factor for fibrinogen production. This quantitative method to measure mRNA may prove very useful for further in vivo analysis of fibrinogen gene transcription.