Beat M. Frey

Intermittent exposure to doxorubicin in vitro selects for multifactorial non‐P‐glycoprotein‐associated multidrug resistance in RPMI 8226 human myeloma cells

The purpose of the present study was to evaluate whether intermittent exposure to a constant dose of doxorubicin selects for multidrug resistance (MDR) in RPMI 8226 human myeloma cells and, if so, to determine the molecular mechanism. In an attempt to approximate clinical doxorubicin treatment in vitro, cells were exposed to a fixed dose of doxorubicin for 4u2003d alternating with growth in drug‐free medium for 17u2003d. An MDR subline emerged, termed 8226/DOXint5, which was 3–4‐fold resistant to doxorubicin, etoposide and m‐AMSA, and 1.6‐fold resistant to vincristine. Sensitivity to docetaxel, melphalan and cisplatin was normal. Verapamil normalized vincristine sensitivity but had little effect on resistance to the other agents. Cellular uptake and retention of daunorubicin and vincristine were reduced by approximately 10%. The 8226/DOXint5 cells showed diminished DNA topoisomerase IIα expression and increased expression of the multidrug resistance protein MRP. Expression of MDR1/P‐glycoprotein was not detected. Immunostaining showed 70% of the cells to over‐express the lung‐resistance protein LRP. This new MDR myeloma cell line may prove to be a useful model for the development of strategies to overcome low‐level, multifactorial MDR, which might be a common phenomenon in clinical myeloma treated with doxorubicin.

MNSs genotyping by MALDI‐TOF MS shows high concordance with serology, allows gene copy number testing and reveals new St(a) alleles

Results of genotyping with true high‐throughput capability for MNSs antigens are underrepresented, probably because of technical issues, due to the high level of nucleotide sequence homology of the paralogous genes GYPA, GYPB and GYPE. Eight MNSs‐specific single nucleotide polymorphisms (SNP) were detected using matrix‐assisted laser desorption/ionization, time‐of‐flight mass spectrometry (MALDI‐TOF MS) in 5800 serologically M/N and S/s pre‐typed Swiss blood donors and 50 individuals of known or presumptive black African ethnicity. Comparison of serotype with genotype delivered concordance rates of 99·70% and 99·90% and accuracy of genotyping alone of 99·88% and 99·95%, for M/N and S/s, respectively. The area under the curve of peak signals was measured in intron 1 of the two highly homologous genes GYPB and GYPE and allowed for gene copy number variation estimates in all individuals investigated. Elevated GYPB:GYPE ratios accumulated in several carriers of two newly observed GYP*401 variants, termed type G and H, both encoding for the low incidence antigen St(a). In black Africans, reduced GYPB gene contents were proven in pre‐typed S‐s‐U‐ phenotypes and could be reproduced in unknown specimens. Quantitative gene copy number estimates represented a highly attractive supplement to conventional genotyping, solely based on MNSs SNPs.

Low-Frequency Blood Group Antigens in Switzerland

Background: High-frequency blood group antigens (HFA) are present in >90% of the human population, according to some reports even in >99% of individuals. Therefore, patients lacking HFA may become challenging for transfusion support because compatible blood is hardly found, and if the patient carries alloantibodies, the cross-match will be positive with virtual every red cell unit tested. Methods: In this study, we applied high-throughput blood group SNP genotyping on >37,000 Swiss blood donors, intending to identify homozygous carriers of low-frequency blood group antigens (LFA). Results: 326 such individuals were identified and made available to transfusion specialists for future support of patients in need of rare blood products. Conclusion: Thorough comparison of minor allele frequencies using population genetics revealed heterogeneity of allele distributions among Swiss blood donors which may be explained by the topographical and cultural peculiarities of Switzerland. Moreover, geographically localized donor subpopulations are described which contain above-average numbers of individuals carrying rare blood group genotypes.

Red blood cell use in Switzerland: trends and demographic challenges.

BACKGROUNDnSeveral studies have raised concerns that future demand for blood products may not be met. The ageing of the general population and the fact that a large proportion of blood products is transfused to elderly patients has been identified as an important driver of blood shortages. The aim of this study was to collect, for the first time, nationally representative data regarding blood donors and transfusion recipients in order to predict the future evolution of blood donations and red blood cell (RBC) use in Switzerland between 2014 and 2035.nnnMATERIALS AND METHODSnBlood donor and transfusion recipient data, subdivided by the subjects age and gender were obtained from Regional Blood Services and nine large, acute-care hospitals in various regions of Switzerland. Generalised additive regression models and time-series models with exponential smoothing were employed to estimate trends of whole blood donations and RBC transfusions.nnnRESULTSnThe trend models employed suggested that RBC demand could equal supply by 2018 and could eventually cause an increasing shortfall of up to 77,000 RBC units by 2035.nnnDISCUSSIONnOur study highlights the need for continuous monitoring of trends of blood donations and blood transfusions in order to take proactive measures aimed at preventing blood shortages in Switzerland. Measures should be taken to improve donor retention in order to prevent a further erosion of the blood donor base.

Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry analysis of 36 blood group alleles among 396 Thai samples reveals region-specific variants: THAI BLOOD GROUPS BY MASS SPECTROMETRY

Blood group phenotype variation has been attributed to potential resistance to pathogen invasion. Variation was mapped in blood donors from Lampang (northern region) and Saraburi (central region), Thailand, where malaria is endemic. The previously unknown blood group allele profiles were characterized and the data were correlated with phenotypes. The high incidence of the Vel‐negative phenotype previously reported in Thais was investigated.

Novel Xp21.1 deletion associated with unusual features in a large McLeod syndrome kindred

McLeod syndrome (MLS) is a rare adult-onset, progressive and incurable X-linked multisystemic disorder characterized by chorea, cognitive decline, seizures, polyneuropathy, myopathy and dilated cardiomyopathy with subsequent heart failure and increased risk for arrhythmia [1]. Variable psychiatric symptoms are common; the presence of acanthocytes on blood smears, elevated CK levels and striatal atrophy are other features. MLS is caused by mutation in the XK gene which encodes a membrane transport protein containing the Kx erythrocyte antigen [1]. So far, less than 200 MLS cases have been reported. In general, women harboring XK mutations rarely manifest symptoms. In addition, myoclonus has not been described in association with MLS and functional imaging studies are scarce.

Too Many Blood Donors - Response Bias in the Swiss Health Survey 2012

Background: Data on blood donor status obtained from general surveys and health interview surveys have been widely used. However, the integrity of data on self-reported blood donor status from surveys may be threatened by sampling and non-sampling error. Our study aimed to compare self-reported blood donors (including one-time as well as regular donors) from the Swiss Health Survey 2012 (SHS) with register-based blood donors recorded by blood establishments and evaluate the direction and magnitude of bias in the SHS. Methods: We compared population-weighted SHS point estimates of the number of blood donors with their corresponding 95% confidence intervals to the respective figures from blood donor registries (birth cohorts 1978-1993) and estimates of donors based on period donor tables derived from blood donor registries (birth cohorts 1920-1993). Results: In the birth cohorts 1978-1993, the SHS-predicted number of donors was 1.8 times higher than the respective number of donors based on registry data. Adjusting for foreign and naturalized Swiss nationals that immigrated after their 18th birthday, the SHS overall predicted number of donors was 1.6 times higher. Similarly, SHS estimates for the 1920-1993 birth cohorts were 2.4 and 2.1 times higher as compared to register-based estimates. Generally, the differences between SHS and register-based donors were more pronounced in men than in women. Conclusion: Self-reported blood donor status in the SHS is biased. Estimates of blood donors are substantially higher than respective estimates based on blood donor registries.