Emergency transfusion with whole blood versus packed red blood cells: A study of 1400 patients

BACKGROUND

Low-titer group O whole blood (LTOWB) is increasingly used for emergency transfusion. We studied whether initial release of LTOWB compared with packed red blood cells (pRBCs) reduced overall blood requirements for patients needing emergency transfusion. Secondary outcomes examined included survival and non-lethal adverse clinical outcomes.

STUDY DESIGN AND METHODS

A retrospective, single-center, before-versus-after study compared patients transfused with emergency-release, uncrossmatched pRBC followed by component therapy (2016-2019) versus patients transfused with emergency-release, uncrossmatched LTOWB followed by component therapy (2019-2022).

RESULTS

Outcomes were available for 602 patients in the pRBC group versus 749 in the whole blood group. The two groups were similar for age, sex, race, estimated blood volume, ABO blood groups, and underlying diagnosis. Use of LTOWB was associated with increased blood product use at 24 h (4.0 (2.0-12.0) in pRBC group versus 6.5 (4.2-12.7) in LTOWB group, p < .0001) and at 7 days (5.5 (3.0-13.0) in pRBC group versus 7.3 (4.3-14.3) in LTOWB group, p < .0001). Initial use of LTOWB was not associated with improved 24 h or 30 day survival nor lower incidence of non-lethal adverse clinical outcomes compared with pRBC.

DISCUSSION

Our study showed a statistically significant increase in total blood use and blood acquisition costs for patients receiving initial emergency transfusion with LTOWB compared with pRBC. The initial use of LTOWB offered no advantage over component therapy for 30 day survival or selected non-lethal adverse outcomes.

Time interval between antibody investigations among patients who demonstrate serial red cell antibody formation

BACKGROUND

Current national standards for pretransfusion testing do not address the frequency or optimal time interval to repeat antibody identification testing for patients in whom antibodies have been previously detected.

STUDY DESIGN AND METHODS

A retrospective review was performed of patients with existing red blood cell (RBC) antibodies who subsequently developed new antibody specificities. Data were drawn from a single institution where the antibody investigation was repeated if the screen suggested a new antibody or if 14 days had elapsed since the previous investigation. Clinically insignificant or drug-dependent antibodies were excluded. Among cases in which new antibodies were detected within 30 days of a previous sample that already demonstrated existing antibodies, the median and lower 95% confidence intervals for the number of days between the detection of the existing and new antibodies were determined.

RESULTS

Over a 9-year period, among 2114 patients with more than 1 antibody, 699 (33%) had serially detected antibodies from separate samples. Among 152 patients whose subsequent antibody was detected within 30 days of the existing antibodies, the median time interval to detection of the new antibody was 13 days. The lower 95% confidence interval was 1 day. By Day 3, 18% of the new antibodies had already appeared.

CONCLUSION

In patients who form multiple antibodies, the serial emergence of clinically significant antibodies is common. In some patients, detection of a new specificity occurs in a sample drawn shortly after the sample that demonstrated the first antibody. These results have implications for the frequency of pretransfusion testing.

Quantitative multiplex PCR analysis for large rearrangements in the MLH1 and MSH2 genes for hereditary non- polyposis colorectal cancer

4109

Background: Hereditary non-polyposis colon cancer (HNPCC) is caused by germline mutations in the mismatch repair genes MLH1, MSH2, MSH6 and PMS2. HNPCC patients have ∼80% increased risk of colon cancer, and elevated risk for cancers of the endometrium, ovary, stomach, small intestine and upper urinary tract. Molecular genetic testing in HNPCC families showed that ∼90% of cases are due to MLH1 and MSH2, 7–10% to MSH6, and <5% to PMS2. The majority are point mutations detectable by sequencing; however, about 5% and 20% of mutations in MLH1 and MSH2, respectively, are large rearrangements that require other detection techniques such as Southern blot or multiplex ligation-dependent probe amplification (MLPA). Our laboratory had previously developed and implemented a quantitative multiplex PCR (QMPCR) endpoint assay for clinical testing for large rearrangements in the BRCA1 and BRCA2 genes. We have developed a similar assay for the MLH1 and MSH2 genes in HNPCC which we refer to as CART (Colorectal cancer Rearrangement Test). Methods: CART consists of 9 multiplexes of 8–12 amplicons each, with at least 2 amplicons targeting each coding exon, promoter, and 3’UTR of both genes. Copy numbers are normalized against MLH1, MSH2, and two unlinked control genes. Internally developed software provides automated analysis and statistical confidence levels for the presence or absence of large rearrangements. Results: Initial validation of CART has been performed on 14 MLH1 or MSH2 rearrangement-positive and 30 negative DNA samples. Results were 100% concordant with previous Southern blot data, as well as supplemental MLPA studies. CART has greatly improved turnaround time, accuracy, and consistency compared to Southerns and MLPA. Conclusions: QMPCR is a superior diagnostic tool for detecting large rearrangements in disease genes. Validation of CART for MLH1 and MSH2 rearrangements is underway on a larger set of previously genotyped samples in a blinded manner. In conjunction with sequencing of the MLH1 and MSH2 genes, the CART assay is expected to improve molecular diagnostic testing on individuals at risk for HNPCC.

No significant financial relationships to disclose.

Molecular genetic testing for large genomic deletion and duplication mutations in the BRCA1 and BRCA2 genes for hereditary breast and ovarian cancer

10513

Background: Mutations in the BRCA1 and BRCA2 genes are comprised of a majority of mutations that are detectable by sequence analysis, and a minority of large genomic deletion and duplication mutations that are detected by methods different than sequencing. Our laboratory developed and implemented a clinical assay for large rearrangements that we refer to as BART (BRCA1/2 Rearrangement Test). We validated the performance of BART using a completely anonymous large number of breast/ovarian cancer patient samples. We also demonstrated superior performance of BART versus other dosage-sensitive methods including Multiplex Ligation-dependent Probe Amplification (MLPA). Methods: BART utilizes quantitative endpoint polymerase chain reaction (PCR) in a multiplexed fluorescent format. Eleven multiplex PCR reactions were designed to contain two amplicons targeting the promoter region, all coding exons, and flanking regions of BRCA1 and BRCA2. An automated likelihood-based analysis application normalizes target amplicon copy number between BRCA1, BRCA2 and three control genes. Deletions and duplications are identified with a statistical confidence level. Results: Based on clinical and family history criteria, 1,035 patients were identified as severe-risk during the initial months of clinical BART analysis at Myriad Genetic Laboratories. All patients were initially tested for Comprehensive BRACAnalysis which includes BRCA1 and BRCA2 full gene sequencing plus large rearrangement panel testing for 5 recurrent BRCA1 mutations. Among severe-risk patients, 302 (29.2%) were positive for a BRCA1 or BRCA2 mutation by sequencing, 9 (0.9%) were positive by large rearrangement panel testing and an additional 27(2.6%) tested positive by BART for large genomic rearrangements. The total detection rate for deleterious mutations in severe-risk individuals was therefore 32.7%. Conclusions: Our initial clinical data indicate that BART testing is appropriate for high-risk patients identified on the basis of personal and family history criteria.

No significant financial relationships to disclose.

Yeast RNA polymerase I enhancer is dispensable for transcription of the chromosomal rRNA gene and cell growth, and its apparent transcription enhancement from ectopic promoters requires Fob1 protein

At the end of the 35S rRNA gene within ribosomal DNA (rDNA) repeats in Saccharomyces cerevisiae lies an enhancer that has been shown to greatly stimulate rDNA transcription in ectopic reporter systems. We found, however, that the enhancer is not necessary for normal levels of rRNA synthesis from chromosomal rDNA or for cell growth. Yeast strains which have the entire enhancer from rDNA deleted did not show any defects in growth or rRNA synthesis. We found that the stimulatory activity of the enhancer for ectopic reporters is not observed in cells with disrupted nucleolar structures, suggesting that reporter genes are in general poorly accessible to RNA polymerase I (Pol I) machinery in the nucleolus and that the enhancer improves accessibility. We also found that a fob1 mutation abolishes transcription from the enhancer-dependent rDNA promoter integrated at the HIS4 locus without any effect on transcription from chromosomal rDNA. FOB1 is required for recombination hot spot (HOT1) activity, which also requires the enhancer region, and for recombination within rDNA repeats. We suggest that Fob1 protein stimulates interactions between rDNA repeats through the enhancer region, thus helping ectopic rDNA promoters to recruit the Pol I machinery normally present in the nucleolus.