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F F Wagner

Publications and source records attributed to F F Wagner.

At least 37 records · Page 2Linked to original sources
PubMed1997

RHD/CE typing by polymerase chain reaction using sequence-specific primers.

BACKGROUND: Current DNA-based Rh system typing strategies may detect the two RH genes and their prevalent alleles, but they are known to fail sometimes, when rare RH alleles (e.g., D category phenotypes) are encountered. It is almost impossible to find a single DNA-based method that can accommodate the great heterogeneity within the human Rh system. STUDY DESIGN AND METHODS: An easy-to-perform DNA-based method for the detection of the two RH genes and their alleles, including variant RHD alleles, was developed. By the use of one RHD/C-, seven RHD-, and four RHCE-specific polymerase chain reactions, all triggered to work at identical thermocycling conditions, the DNA of 77 blood donors carrying weak D and that of 200 random donors with common D phenotype was investigated. In addition, 77 selected samples of ccDee and rare Rh system phenotypes were examined. RESULTS: Among 77 samples of weak D, one Rh33 and six DVI categories were detected, one of which showed new RHD-specific nucleotide patterns. In DFR and CCee samples, novel variant RHD alleles were found. RHD DNA types of 200 random donors were found to be concordant with their D phenotype. For RHE and RHe genotyping, a full correlation with serologic phenotypes was found. Our method for genotyping RHC and RHc failed in some cases, because of an already published RHc allelic variation, which we have called RHc(cyt48). An estimate of the frequency of this RHc(cyt48) allele in a white population was made. CONCLUSION: The presented exon-scanning RHD/CE polymerase chain reaction using sequence-specific primers complements current DNA-based Rh system typing strategies and is superior in the detection of variant RHD alleles.

Blood Donors↗
PubMed1997

Polymorphism of the h allele and the population frequency of sporadic nonfunctional alleles.

BACKGROUND: Current polymerase chain reaction-based strategies for phenotype prediction often fail when sporadic nonfunctional alleles are encountered. The population frequency of such mutations was not known for any gene under low selection pressure and may be best examined in blood groups systems lacking prevalent nonfunctional alleles. The frequency of the very rare Bombay blood group (Oh, genotype hh sese) was recently determined in a systematic survey of more than 600,000 white individuals. STUDY DESIGN AND METHODS: With this survey used in conjunction with additional blood samples, the population frequency of nonfunctional alleles of the gene encoding the alpha (1,2)fucosyltransferase (H or FUT1) was determined. RESULTS: Seven different h alleles were found in five unrelated individuals, three of whom were homozygous for unique alleles. There was no prevalent h allele. Five missense and one frameshift mutations were observed, that were the presumptive causes of the null phenotype; the coding sequence of one h allele was identical to the H sequence. The average inbreeding factor alpha was 0.00116. The frequency of nonfunctional alleles at the H gene locus was calculated as 1 in 347 in a large white population (95% CI: 1:185-1:824). CONCLUSION: The Bombay blood group phenotype in white is due to diverse, sporadic, nonfunctional alleles without any prevalent allele. Assuming similar rates of nonfunctional alleles in glycosyltransferase genes like ABO, current genotyping strategies may fail as often as once in about 300 individuals of blood group O. Sporadic neutral alleles may also pose a serious obstacle for population-wide screening of many disease-associated genes.

Alleles↗
PubMed1997

[D-category VII depends on amino acid substitution Leu(110)Pro].

A point mutation has been postulated as cause of the phenotype D category VII, based on data of 3 probands only. Repeatedly, D protein variants have been found to be due to heterogenous molecular events. Therefore, the aforementioned cause was to be tested with more probands. In a systematic study, 68 nonrelated probands with D category VII were found. 33 were selected by chance, and the nucleic acid region 280-329 was sequenced after PCR amplification. All examined probands showed the postulated Leu(110)Pro substitution. No further polymorphisms were detected. Our data show that in Southern Germany D category VII is homogenously due to the amino acid substitution Leu(110)Pro. This allows the exploitation of this polymorphism for the prenatal detection of D category VII and the related Tar antigen.

Amino Acid Substitution↗
PubMed1996

RHD antigen density and agglutination in RHD variant red cells.

For the Rhesus categories DIV, DVI, and DVII, agglutination was compared to the number of RHD antigens per cell. We detected 3,100 to 15,400 antigens/cell on DVI. We report examples of anti-D reactivity showing lack of specificity and pointing to the known serologic split in DIV and DVI. Such a split was not found in DVII. Other examples were explained by lack of sensitivity. These results emphasized the need to consider RHD antigen densities, before a serologic split in RHD variant cells is postulated. In this context, flow cytometry may be superior to agglutination titers to determine antigen densities.

Agglutination Tests↗
PubMed1996

RHD epitope density profiles of RHD variant red cells analyzed by flow cytometry.

For DII and DIVa, RHD antigen sites per cell were tested previously only with a limited number of radio labelled anti-D. We determined RHD antigen densities (sites/cell) by flow cytometry with 64 anti-D in four partial RHD red cells. Epitope densities detected (mean +/- SD) were: DVII 8,000 +/- 1,665 (number of anti-D used for calculation: n = 55; percentage of reference cells: 47%); DNU (DIIlike) 6,869 +/- 1,381 (n = 47; 29%); and DHMii 20,626 +/- 4,320 (n = 55; 87%). One DIV cell revealed two peaks with a low fluorescence range of 18,158 +/- 2,504 (n = 11; 76%) and a high range of 35,477 +/- 2,485 (n = 6; 149%). We established epitope density profiles with a large panel of anti-D for four RHD variant cells and determined the number of RHD antigens per cell.

Epitopes↗
PubMed1995

Transfusion-associated graft-versus-host disease: risk due to homozygous HLA haplotypes.

BACKGROUND: Transfusion-associated graft-versus-host disease (TA-GVHD) may occur in transfusions of blood from HLA-homozygous persons to HLA-heterozygous persons who share a haplotype. STUDY DESIGN AND METHODS: Two mathematical models were developed to calculate the upper and lower limit of the associated risks in various populations using a combination of serology- and DNA sequence-based HLA haplotype frequencies. RESULTS: For nondirected transfusion, the range of the estimated risk in United States whites is 1 of 17,700 to 39,000 (1/6,900-48,500 in Germans; 1/1,600-7,900 in Japanese). The risk in directed donation between parents and children is increased at least 21-fold for US whites, 18-fold for Germans, and 11-fold for Japanese. CONCLUSION: For nondirected transfusions, the estimates of TA-GVHD risk derived in this model are lower than estimates of previously published models, are in better agreement with the clinical experience, and explain in part the observed discrepancy between TA-GVHD incidence in the United States and that in Japan. Most notably for US whites, the relative increase in risk in directed transfusion is larger than previously thought.

Gene Frequency↗
PubMed1995

Frequencies of the blood groups ABO, Rhesus, D category VI, Kell, and of clinically relevant high-frequency antigens in south-western Germany.

BACKGROUND: Current estimates of blood group frequencies in Germany were often derived from studies involving less than 12,000 individuals. The frequency of the D category VI was unknown. METHODS: ABO. Kell, and Rhesus blood group data of more than 600,000 donors were reviewed. Allele frequencies were derived by the maximum-likelihood method. The frequency of D category VI was determined in more than 70,000 Rhesus typings. RESULTS: ABO allele frequencies were: O: 0.640, A: 0.279. B: 0.081. Rhesus haplotype frequencies were: cde: 0.394, CDe: 0.431, cDE: 0.136, cDe: 0.021, and Cde: 0.011. D category VI represented 7%, of all weak D (formerly D(u)). The 95% confidence interval for the D category VI frequency was 1:3,600-1:11,200. Kell allele frequencies were: K: 0.040, and k: 0.960, 95% confidence intervals for rare phenotypes were: Oh: 1:88,000-1:1,760,000, p: 1:200,000-1:5,200,000. Rh(null): 1:180,000-1:10,300,000, and D-deletion: 1: 180,000-0. CONCLUSIONS: We presented refined estimates of ABO, Rhesus D and Kell blood group frequencies and established reliable frequency estimates for Rhesus haplotype and some rare blood groups. The prevalence of D category VI was about 0.02%, which necessitates specific detection for Rh-D-negative transfusion therapy. A protocol is presented for Rh D typing in transfusion recipients. which obviates the need for an antiglobulin test.

ABO Blood-Group System↗
PubMed1994

Influence of Rh phenotype on the antigen density of C, c, and D: flow cytometric study using a frozen standard red cell.

BACKGROUND: Flow cytometry is increasingly being used for the comparison of antigen density. Indirect immune fluorescence is more sensitive than direct immune fluorescence and thus allows the study of red cells (RBCs) with a weak D antigen. STUDY DESIGN AND METHODS: In indirect immune fluorescence, when the fluorescence is standardized by the use of aliquoted frozen standard RBCs, the coefficient of variation in fluorescence intensity was less than 5 percent, which allows accurate determination of minor variations of Rh antigen density. RESULTS: For D antigen, the well-known suppressive effect of C, and the low antigen density of the weak D phenotype, was demonstrated. Use of epitope-specific monoclonal antibodies yielded similar results and allowed the identification of a D category IV heterozygote; the relative antigen density measured with a monoclonal antibody that reacted with D(IV) was twice that measured with a monoclonal antibody that did not react with D(IV). RBCs from C and c homozygotes had significantly more antigen than those from heterozygotes. There was significant variation in antigen density, depending on Rh phenotype: for example, D+ RBCs had less C antigen than D- RBCs, and Rh:1,2,-3,4,5 (CcDee) RBCs had more c antigen than Rh:1,2,3,4,5 (CcDEe) RBCs. There was no difference in D, C, and c antigen density in neonatal and adult RBCs. CONCLUSION: Flow cytometry is an excellent tool for the demonstration of minor differences in antigen density.

Adult↗