ABO-immune complex formation and impact on platelet function, red cell structural integrity and haemostasis: an in vitro model of ABO non-identical transfusion.

BACKGROUND: Transfusion of ABO non-identical platelets has been associated with fatal haemolytic reactions, increased red cell transfusion needs and other adverse effects, but the practice of ABO matching in platelet transfusion is controversial. Immune complexes can be formed from the anti-A and/or anti-B antibodies and ABO soluble antigen(s) present in donor and recipient plasma after ABO non-identical transfusions. We hypothesized that these immune complexes affect recipient red cell structural integrity, platelet function and haemostasis. STUDY DESIGN AND METHODS: Haemolysis, platelet function and haemostatic function were assessed before and after incubation of recipient red cells, platelets and whole blood with normal saline controls, ABO-identical plasma controls or in vitro-generated ABO-immune complexes. RESULTS: ABO-immune complexes caused significantly increased haemolysis (P < 0·001), inhibition of platelet function (P = 0·001) and disruption of clot formation kinetics (P < 0·005) in both group A and O recipient samples. CONCLUSIONS: Substantial changes in platelet function, red cell integrity and haemostasis occur after in vitro exposure to immune complexes. These in vitro findings may explain, in part, previously observed associations of ABO non-identical platelet transfusions with adverse effects including increased red cell transfusion needs, organ failure and mortality.

Quality of factor XI activity testing in North American Specialized Coagulation Laboratories.

INTRODUCTION: The performance of factor XI activity (FXI) by laboratories in the North American Specialized Coagulation Laboratory Association proficiency testing program was analyzed. METHODS: Over 10 years (2003-2013), 80 samples were distributed; 33-55 laboratories participated per exercise providing 3833 total responses. Analysis was performed on numeric results and qualitative classification of results. RESULTS: The sample FXI levels ranged from 3.8 to 154.0 IU/dL. The overall interlaboratory average coefficient of variation (CV%) was 17.5%; the CV was higher for a sample with low (3.8 IU/dL) FXI. Results were correctly classified as abnormal (100%) for a sample with 3.8 IU/dL FXI and normal/borderline normal (97.7%) for 45 samples with 80 to < 140 IU/dL FXI. The classification was heterogeneous for samples with FXI of 50 to < 80 IU/dL. Six specimens were repeat-tested from 2007 to 2013. The mean FXI was not significantly different in laboratories using the same method on both exercises, suggesting good intralaboratory precision over time. Univariate analysis of data from 2011 to 2012 did not find a consistent significant difference among the activators, analyzers, calibrators, and FXI-deficient plasmas. CONCLUSION: Laboratories generally performed well in assessment of FXI based on interlaboratory precision when FXI >30 IU/dL and on classification of samples with very low or normal FXI.

Ethyl arachidonate is the predominant fatty acid ethyl ester in the brains of alcohol-intoxicated subjects at autopsy.

The role of fatty acid ethyl esters (FAEE), the nonoxidative ethanol metabolites, as mediators of alcohol-induced organ damage is increasingly being recognized. FAEE are detectable in the blood and in liver and adipose tissue after ethanol ingestion, and on that basis, FAEE can be used as markers of ethanol intake. In this study, 10 samples of human brain were collected at autopsy at the Massachusetts Medical Examiner's Office and analyzed for FAEE. FAEE were isolated and quantified as mass per gram of wet weight. The blood ethanol level was also obtained in each case along with the other drugs detected in routine postmortem toxicology screening tests. Ethyl arachidonate was the predominant FAEE species in the brain, representing up to 77.4% of total FAEE in the brain. The percent age of ethyl arachidonate of the total FAEE in the brain was significantly higher than what has been found in all other organs and tissues previously analyzed. Linoleate, the precursor of arachidonate, was a poor substrate for FAEE synthesis, as the percentage of ethyl linoleate of the total FAEE content was extremely low. Thus, this reflects preferred incorporation of arachidonate into newly synthesized FAEE in the brain. Since arachidonate is derived from linoleate, which is depleted in FAEE while arachidonate is enriched, the synthesis of FAEE may be linked to the desaturation and elongation of linoleate to arachidonate.

Factor VII assay performance: an analysis of the North American Specialized Coagulation Laboratory Association proficiency testing results.

The performance of factor VII (FVII) assays currently used by clinical laboratories was examined in North American Specialized Coagulation Laboratory Association (NASCOLA) proficiency tests. Data from 12 surveys conducted between 2008 and 2010, involving 20 unique specimens plus four repeat-tested specimens, were analyzed. The number of laboratories per survey was 49-54 with a total of 1224 responses. Numerous reagent/instrument combinations were used. For FVII > 80 or <40 U/dL, 99.5% of results (859/863) were correctly classified by laboratories as normal/abnormal. Classification of specimens with 40-73 U/dL FVII was heterogeneous. Interlaboratory precision was better for normal specimens (coefficient of variation (CV) 10.7%) than for FVII<20 U/dL (CV 33.1%), with a mean CV of 17.2% per specimen. Intralaboratory precision for repeated specimens demonstrated no significant difference between the paired survey results (mean absolute difference 2.5-5.0 U/dL). For specimens with FVII >50 U/dL, among commonly used methods, one thromboplastin and one calibrator produced results 5-6 U/dL higher and another thromboplastin and calibrator produced results 5-6 U/dL lower than all other methods, and human thromboplastin differed from rabbit by +7.6 U/dL. Preliminary evidence suggests these differences could be due to the calibrator. For FVII <50 U/dL, differences among the commonly used reagents and calibrators were generally not significant.

Fatty acid ethyl esters in liver and adipose tissues as postmortem markers for ethanol intake.

BACKGROUND: Fatty acid ethyl esters (FAEEs) are nonoxidative metabolites of ethanol. FAEEs are found in liver, pancreas, and adipose tissues up to 24 h after consumption of ethanol, and on that basis, they are potentially useful markers for ethanol intake. In this study with rats, we investigated the efficacy of using FAEEs in liver and in adipose tissue as postmortem markers for premortem ethanol ingestion. METHODS: An animal study was conducted in which test rats received injections of ethanol and control rats received injections of normal saline. The rats were killed 2 h after the injections. The bodies of the animals were stored at 4 degrees C up to 12 h, and samples of liver and adipose tissues were collected at different time intervals and processed for FAEE quantification. In another set of experiments, the rats received injections and were killed as described above, but bodies of animals from both groups were stored at 4, 25, or 37 degrees C for up to 72 h, and liver samples were collected and processed for FAEE quantification. RESULTS: FAEEs were detected up to 12 h after death in liver and adipose tissue samples from the bodies of ethanol-treated animals stored at 4 degrees C; negligible amounts were detected in the bodies of animals that received normal saline. Adipose tissues contained higher amounts of FAEEs than liver, as well as more species: eight FAEE species in adipose tissue and five in liver tissue. Higher concentrations of FAEEs were detected in livers of treated animals stored at 25 degrees C for up to 48 h than in livers of controls stored under the same conditions. CONCLUSIONS: For at least 12 h after death, FAEEs in liver and adipose tissues are useful postmortem markers of premortem ethanol ingestion.

Differences in the fatty acid composition of fatty acid ethyl esters in organs and their secretions.

BACKGROUND: Fatty acid ethyl esters (FAEE) are nonoxidative ethanol metabolites that have been shown to be long term markers of ethanol intake and have been implicated as mediators of ethanol-induced cell injury. Previous studies have indicated that the fatty acid composition of the FAEE found in the plasma of human subjects after ethanol ingestion is predominantly ethyl palmitate and ethyl oleate. This raised the possibility that there is some selectivity toward the fatty acid used for FAEE to be exported from the liver into the blood. METHODS: To address the hypothesis that the fatty acid composition of FAEE secreted from organs, such as the liver and pancreas, differs from the fatty acid composition of FAEE in the organs, this study was performed using rats that received ethanol by intra-arterial infusion. RESULTS: It was found that the fatty acids in FAEE differed significantly in plasma versus liver, bile versus liver, and pancreatic secretions versus pancreas. CONCLUSIONS: These results indicate that organs selectively export certain FAEE species.