Clinical features and genetic defect in six index patients with congenital fibrinogen disorders: Three novel mutations with one common mutation in Taiwan's population.

INTRODUCTION: Congenital fibrinogen disorders (CFDs) are caused by mutations in fibrinogen-encoding genes, FGA, FGB, and FGG, which lead to quantitative or qualitative abnormalities of fibrinogen. Although the diagnosis of CFDs is based on antigenic and functional level of fibrinogen, few genotypes are clearly correlated with phenotype. METHODS: In this study, we investigated all of the referred patients diagnosed as CFDs in Taiwan's population between 1995 and 2020. Clinical features, laboratory data and genetic defects were analysed. Functional fibrinogen level was determined by the Clauss method. Antigenic fibrinogen was measured by an enzyme-linked immunosorbent assay. Fibrinogen genes were assessed for mutations by polymerase chain reaction and sequencing. RESULTS: A total of 18 patients from six unrelated families with CFDs were identified. One patient from a consanguineous family was diagnosed as afibrinogenemia type 1A with a novel homozygous frameshift mutation in FGB exon 4. The other five (83.3 %) index patients were all diagnosed as dysfibrinogenemia type 3A caused by two novel and one known mutation. Six (33.3 %) patients from three families had a novel mutation in FGB exon 8. The clinical features and laboratory data were highly variable among these patients with the same mutation. CONCLUSIONS: Three novel mutations of CFDs causing afibrinogenemia and dysfibrinogenemia were identified. The point mutation in FGB exon 8 is also a common mutation in Taiwan's population. Considerable phenotypic variability among the patients with an identical mutation was observed.

Trends and antimicrobial resistance of pathogens causing bloodstream infections among febrile neutropenic adults with hematological malignancy.

BACKGROUND AND PURPOSE: The microbiological spectrum in cancer patients with febrile neutropenia has changed over the past several decades in western countries. The growing incidence of antimicrobial resistance is an inevitable consequence of the widespread use of antibiotics in medical settings. The aim of this study was to clarify the trends and antimicrobial resistance among pathogens causing bloodstream infections in febrile neutropenic adults with hematological malignancies. METHODS: The characteristics of pathogens causing bloodstream infection isolated from patients with febrile neutropenia who were treated at National Taiwan University Hospital from 1996 to 2001 were reviewed. A total of 1174 pathogens were isolated from 3093 admissions to a hematological ward during this period. Among them, 738 isolates were recovered from patients with febrile neutropenia. RESULTS: The majority (93%) of these neutropenic febrile patients had underlying acute leukemia or lymphoma. Gram-negative bacteria accounted for 57% of isolated pathogens, followed by Gram-positive bacteria (32%), fungi (7%), and anaerobes (3%). In decreasing frequency, Escherichia coli (13%), Klebsiella pneumoniae (12%), Enterobacter cloacae (7%), Pseudomonas aeruginosa (6%), and Acinetobacter baumannii (5%) were the predominant Gram-negative bacteria, while coagulase-negative staphylococci (13%), viridans group streptococci (4%), and Staphylococcus aureus (4%) were the major Gram-positive pathogens. Two-thirds (20/30) of S. aureus isolates were resistant to oxacillin. No vancomycin-resistant enterococci were isolated. Resistance to cefotaxime was found in 63% of E. cloacae, 13% of K. pneumoniae and 10% of E. coli. Overall, 33% of E. coli and 13% of K. pneumoniae were resistant to ciprofloxacin. CONCLUSIONS: This study indicates that the microbiological spectrum of microorganisms causing bloodstream infections in neutropenic febrile patients with hematological malignancies at National Taiwan University Hospital is different from western countries in that Gram-negative bacteria remain the predominant pathogens. Antimicrobial resistance among these pathogens is high and E. coli and K. pneumoniae isolates with resistance to third-generation cephalosporins and ciprofloxacin are increasing.

Additional chromosomal abnormalities and variability of BCR breakpoints in Philadelphia chromosome/BCR-ABL-positive acute lymphoblastic leukemia in Taiwan.

From 1986 to 1998, 26 (23%) of 114 adult acute lymphoblastic leukemia (ALL) patients and 11 (4%) of 328 pediatric patients were found to have Philadelphia (Ph) chromosome. In the 30 patients with available data at diagnosis, 18 (60%) had extra-chromosomal abnormalities. They included 1q duplication (5/18, 28%), supernumerary Ph chromosome (4/18, 22%), 9p abnormalities (3/18, 17%), 7q deletion/monosomy 7 (3/18, 17%), trisomy 19 (1/18, 6%), and trisomy 8 (1/18, 6%). Excluding those with specific cytogenetic changes, only one patient had hyperdiploid karyotype with more than 50 chromosomes. The incidence of 1q duplication was higher and that of hyperdiploidy was lower in this study than has been previously reported. There was no prognostic implication of these additional cytogenetic abnormalities. With fluorescence in situ hybridization (FISH) and reverse transcription-polymerase chain reaction (RT-PCR), 14 (27%) of 53 unselected adult ALL patients and 2 (5%) of 38 unselected pediatric patients were BCR-ABL-positive, including one adult and two children without Ph chromosome. The BCR-ABL fusion genes/transcripts were also present in all other 16 selected Ph-positive ALL patients. The BCR-ABL fusion subtypes were determined in all these 32 patients: 91% (11/12) childhood cases showed m-type fusion gene while 45% (9/20) adult ones did so (P = 0.0083). The clinical outcome was similar between the two groups of patients with m-type and M-type BCR-ABL. In conclusion, both cytogenetic and molecular studies are very helpful for identifying the subgroup of ALL patients with Ph/BCR-ABL. The additional cytogenetic abnormalities and subtypes of BCR-ABL fusion genes/transcripts had no significant implications in this group of patients.

Reduction of leukocyte count is associated with thalidomide response in treatment of multiple myeloma.

Fifty Taiwanese patients with relapsed and/or refractory multiple myeloma (MM) were treated with thalidomide on a dose-escalation schedule, commencing with 100 mg/d nightly and incremented either to the maximally tolerated dose or 800 mg/d. Twenty-two patients (44%) responded, with 10 (45.5%) classified as partial remission and 12 (54.5%) minimal response (MR). Complete response did not occur. Of the 28 non-responders, 14 were progressive disease and 14 stable. The median time from commencement of thalidomide treatment to initial achievement of MR was 29 days (range, 8~155), and the corresponding thalidomide dose was 200 mg/d (range, 100~500). The median tolerated dose of thalidomide for the entire sample was 400 mg/d (range, 100~800), with only two (4%) able to tolerate 800 mg/d. Comparing responsive and non-responsive patients, statistically significant differences were not demonstrated for any characteristics except for CRP level and percentage cytogenetic change, which was slightly higher in the latter group relative to the former. Of particular interest, 18 of the 22 responders experienced transient reduction of leukocyte count preceding the attainment of significant reduction in M-proteins in comparison to only four of the 28 non-responders (82% vs. 14%; p<0.001). The median time from commencement of thalidomide treatment to attainment of minimal leukocyte count was 28 days (range, 7~150), with a mean of 2.19x10(9)/l (range, 0.96~3.35x10(9)/l). Leukopenia was generally transient, with rapid recovery despite subsequent continuation of thalidomide. Levels of other non-hematologically adverse effects attributed solely to thalidomide were generally acceptable. For 25 patients, thalidomide treatment was supplemented with low-dose dexamethasone (4 mg, every other day). Of these, 11 had relapsed from and 14 were primarily refractory to thalidomide treatment. Nine of the 25 dexamethasone-supplemented patients were responders (36%). Of particular note were the unusual events noted with this thalidomide-dexamethasone combination, including vascular thrombosis, acute cholecystitis, idiopathic interstitial lung disease and sudden cardiac death. Our results suggest that thalidomide is also effective for Taiwanese patients with refractory and/or relapsed MM. Importantly, the transient reduction in leukocyte count after commencement of thalidomide treatment may serve as a clinical predictor for response. Adverse effects should be carefully monitored when combining thalidomide and dexamethasone, however.