Molecular Genetic Screening in Patients With ACE Inhibitor/Angiotensin Receptor Blocker-Induced Angioedema to Explore the Role of Hereditary Angioedema Genes.

Angioedema is a relatively rare but potentially life-threatening adverse reaction to angiotensin-converting enzyme inhibitors (ACEi) and angiotensin receptor blockers (ARBs). As with hereditary forms of angioedema (HAE), this adverse reaction is mediated by bradykinin. Research suggests that ACEi/ARB-induced angioedema has a multifactorial etiology. In addition, recent case reports suggest that some ACEi/ARB-induced angioedema patients may carry pathogenic HAE variants. The aim of the present study was to investigate the possible association between ACEi/ARB-induced angioedema and HAE genes via systematic molecular genetic screening in a large cohort of ACEi/ARB-induced angioedema cases. Targeted re-sequencing of five HAE-associated genes (SERPING1, F12, PLG, ANGPT1, and KNG1) was performed in 212 ACEi/ARB-induced angioedema patients recruited in Germany/Austria, Sweden, and Denmark, and in 352 controls from a German cohort. Among patients, none of the identified variants represented a known pathogenic variant for HAE. Moreover, no significant association with ACEi/ARB-induced angioedema was found for any of the identified common [minor allele frequency (MAF) >5%] or rare (MAF < 5%) variants. However, several non-significant trends suggestive of possible protective effects were observed. The lowest p-value for an individual variant was found in PLG (rs4252129, p.R523W, p = 0.057, p.adjust > 0.999, Fisher's exact test). Variant p.R523W was found exclusively in controls and has previously been associated with decreased levels of plasminogen, a precursor of plasmin which is part of a pathway directly involved in bradykinin production. In addition, rare, potentially functional variants (MAF < 5%, Phred-scaled combined annotation dependent depletion score >10) showed a nominally significant enrichment in controls both: 1) across all five genes; and 2) in the F12 gene alone. However, these results did not withstand correction for multiple testing. In conclusion, our results suggest that HAE-associated mutations are, at best, a rare cause of ACEi/ARB-induced angioedema. Furthermore, we were unable to identify a significant association between ACEi/ARB-induced angioedema and other variants in the investigated genes. Further studies with larger sample sizes are warranted to draw more definite conclusions concerning variants with limited effect sizes, including protective variants.

High expression of neutrophil and monocyte CD64 with simultaneous lack of upregulation of adhesion receptors CD11b, CD162, CD15, CD65 on neutrophils in severe COVID-19.

BACKGROUND AND AIMS: The pronounced neutrophilia observed in patients with coronavirus disease 2019 (COVID-19) infections suggests a role for these leukocytes in the pathology of the disease. Monocyte and neutrophil expression of CD64 and CD11b have been reported as early biomarkers to detect infections. The aim of this study was to study the expression of receptors for IgG (CD64) and adhesion molecules (CD11b, CD15s, CD65, CD162, CD66b) on neutrophils and monocytes in patients with severe COVID-19 after admission to an intensive care unit (ICU). METHODS: The expression of receptors was analyzed using flow cytometry. EDTA blood from 23 patients with confirmed COVID-19 infection was sampled within 48 h of admission to the ICU. Leukocytes were labeled with antibodies to CD11b, CD15s, CD65s, CD162, CD64, and CD66b. Expression of receptors was reported as mean fluorescence intensity (MFI) or the percentage of cells expressing receptors. RESULTS: Results are presented as comparison of COVID-19 patients with the healthy group and the receptor expression as MFI. Neutrophil receptors CD64 (2.5 versus 0.5) and CD66b (44.5 versus 34) were increased and CD15 decreased (21.6 versus 28.3) when CD65 (6.6 versus 4.4), CD162 (21.3 versus 21.1) and CD11b (10.5 versus 12) were in the same range. Monocytes receptors CD64 (30.5 versus 16.6), CD11b (18.7 versus 9.8), and CD162 (38.6 versus 36.5) were increased and CD15 decreased (10.3 versus 17.9); CD65 were in the same range (2.3 versus 1.96). CONCLUSION: Monocytes and neutrophils are activated during severe COVID-19 infection as shown by strong upregulation of CD64. High monocyte and neutrophil CD64 can be an indicator of a severe form of COVID19. The adhesion molecules (CD11b, CD162, CD65, and CD15) are not upregulated on otherwise activated neutrophils, which might lead to relative impairment of tissue migration. Low adhesion profile of neutrophils suggests immune dysfunction of neutrophils. Monocytes maintain upregulation of some adhesion molecules (CD11b, CD162) suggesting the persistence of an increased ability to migrate into tissues, even during a severe stage of COVID-19. Future research should focus on CD64 and CD11b kinetics in the context of prognosis.

Exome Sequencing Reveals Common and Rare Variants in F5 Associated With ACE Inhibitor and Angiotensin Receptor Blocker-Induced Angioedema.

Angioedema occurring in the head and neck region is a rare and sometimes life-threatening adverse reaction to angiotensin-converting enzyme inhibitors (ACEIs) and angiotensin receptor blockers (ARBs). Few studies have investigated the association of common variants with this extreme reaction, but none have explored the combined influence of rare variants yet. Adjudicated cases of ACEI-induced angioedema (ACEI-AE) or ARB-induced angioedema (ARB-AE) and controls were recruited at five different centers. Sequencing of 1,066 samples (408 ACEI-AE, ARB-AE, and 658 controls) was performed using exome-enriched sequence data. A common variant of the F5 gene that causes an increase in blood clotting (rs6025, p.Arg506Gln, also called factor V Leiden), was significantly associated with both ACEI-AE and ARB-AE (odds ratio: 2.85, 95% confidence interval (CI), 1.89-4.25). A burden test analysis of five rare missense variants in F5 was also found to be associated with ACEI-AE or ARB-AE, P = 2.09 × 10-3 . A combined gene risk score of these variants, and the common variants rs6025 and rs6020, showed that individuals carrying at least one variant had 2.21 (95% CI, 1.49-3.27, P = 6.30 × 10-9 ) times the odds of having ACEI-AE or ARB-AE. The increased risk due to the common Leiden allele was confirmed in a genome-wide association study from the United States. A high risk of angioedema was also observed for the rs6020 variant that is the main coagulation defect-causing variant in black African and Asian populations. We found that deleterious missense variants in F5 are associated with an increased risk of ACEI-AE or ARB-AE.

Genome-wide association study of angioedema induced by angiotensin-converting enzyme inhibitor and angiotensin receptor blocker treatment.

Angioedema in the mouth or upper airways is a feared adverse reaction to angiotensin-converting enzyme inhibitor (ACEi) and angiotensin receptor blocker (ARB) treatment, which is used for hypertension, heart failure and diabetes complications. This candidate gene and genome-wide association study aimed to identify genetic variants predisposing to angioedema induced by these drugs. The discovery cohort consisted of 173 cases and 4890 controls recruited in Sweden. In the candidate gene analysis, ETV6, BDKRB2, MME, and PRKCQ were nominally associated with angioedema (p < 0.05), but did not pass Bonferroni correction for multiple testing (p < 2.89 × 10-5). In the genome-wide analysis, intronic variants in the calcium-activated potassium channel subunit alpha-1 (KCNMA1) gene on chromosome 10 were significantly associated with angioedema (p < 5 × 10-8). Whilst the top KCNMA1 hit was not significant in the replication cohort (413 cases and 599 ACEi-exposed controls from the US and Northern Europe), a meta-analysis of the replication and discovery cohorts (in total 586 cases and 1944 ACEi-exposed controls) revealed that each variant allele increased the odds of experiencing angioedema 1.62 times (95% confidence interval 1.05-2.50, p = 0.030). Associated KCNMA1 variants are not known to be functional, but are in linkage disequilibrium with variants in transcription factor binding sites active in relevant tissues. In summary, our data suggest that common variation in KCNMA1 is associated with risk of angioedema induced by ACEi or ARB treatment. Future whole exome or genome sequencing studies will show whether rare variants in KCNMA1 or other genes contribute to the risk of ACEi- and ARB-induced angioedema.

The HemoCue WBC DIFF system could be used for leucocyte and neutrophil counts but not for full differential counts.

AIM: The aim of this study was to evaluate the HemoCue WBC DIFF system for point of care testing of fingerstick samples from paediatric patients. METHODS: We analysed 158 white blood cell counts on both the point of care HemoCue WBC DIFF instrument and the Cell Dyn Sapphire cell counter used by our central laboratory and compared the results. The measurements were performed using fingerstick samples drawn by nurses working in paediatric emergency and paediatric oncology units. RESULTS: There was good agreement between the two instruments for white blood cell and neutrophil counts. The correlation was weaker for lymphocytes, and the correlations were poor for monocytes and eosinophils. The HemoCue WBC DIFF flagged 56 of the 148 capillary drawn samples as abnormal, but none of the 10 venously collected samples. Only two of the flagged samples differed significantly between the instruments, with regard to the cell counts. CONCLUSION: The correlations between the white blood cell counts and neutrophil counts in this real-life study were good enough to diagnose children in emergency department and oncology unit settings. However, the high number of pathological flags from fingerstick samples, which made reruns necessary, limited the usefulness of the instrument.

Comparison of Clinical Factors Between Patients With Angiotensin-Converting Enzyme Inhibitor-Induced Angioedema and Cough.

BACKGROUND: Angioedema is a rare and serious adverse drug reaction (ADR) to angiotensin-converting enzyme (ACE) inhibitor treatment. Dry cough is a common side effect of ACE inhibitors and has been identified as a possible risk factor for angioedema. OBJECTIVE: We compared characteristics between patients with ACE inhibitor-induced angioedema and cough with the aim of identifying risk factors that differ between these adverse events. METHODS: Data on patients with angioedema or cough induced by ACE inhibitors were collected from the Swedish database of spontaneously reported ADRs or from collaborating clinicians. Wilcoxon rank sum test, Fisher's exact test, and odds ratios (ORs) with 95% CIs were used to test for between-group differences. The significance threshold was set to P <0.00128 to correct for multiple comparisons. RESULTS: Clinical characteristics were compared between 168 patients with angioedema and 121 with cough only. Smoking and concomitant selective calcium channel blocker treatment were more frequent among patients with angioedema than cough: OR = 4.3, 95% CI = 2.1-8.9, P = 2.2 × 10-5, and OR = 3.7, 95% CI = 2.0-7.0, P = 1.7 × 10-5. Angioedema cases were seen more often in male patients (OR = 2.2, 95% CI = 1.4-3.6, P = 1.3 × 10-4) and had longer time to onset and higher doses than those with cough ( P = 3.2 × 10-10 and P = 2.6 × 10-4). A multiple model containing the variables smoking, concurrent calcium channel blocker treatment, male sex, and time to onset accounted for 26% of the variance between the groups. CONCLUSION: Smoking, comedication with selective calcium channel blockers, male sex, and longer treatment time were associated with ACE inhibitor-induced angioedema rather than cough.

Neutrophil CD64 expression - comparison of two different flow cytometry protocols on EPICs MCL and the Leuko64(™) assay on a Celldyn Sapphire haematology analyser.

OBJECTIVE: To evaluate the Trillium Diagnostics Leuko64(™) assay on Abbott Celldyn Sapphire haematology analyser compared to two flow cytometry protocols on Beckman Coulter EPICS MCL flow cytometer. MATERIALS AND METHODS: CD64 expression on neutrophils was determined by two flow cytometry protocols and by a commercial assay on an automatic haematology analyser. The inclusion of study subjects was based on elevated procalcitonin (PCT) values, identifying patients where a systemic infection was suspected. Healthy blood donors were used as a reference group. RESULTS: Statistically significant correlations between the Trillium Diagnostics Leuko64(™) assay and the flow cytometry methods were found when measuring neutrophil CD64 expression. CONCLUSIONS: The good correlation between a reference method and an automated haematology analyser method for CD64 expression on neutrophils supports introduction of the latter assay for routine use as an independent biomarker of bacterial infection and inflammation.

An extragranular compartment of blood eosinophils contains eosinophil protein X/eosinophil-derived neurotoxin (EPX/EDN).

Serum and plasma profiles of eosinophil protein X (EPX/EDN) and those of other eosinophil proteins differ in various conditions, suggesting a different mobilisation from storage granules. This work studied the subcellular localisation of EPX/EDN in non-primed and in vivo primed blood eosinophils from healthy and allergic subjects, during and out of the pollen season. Primed eosinophils contain easily mobilisable secretory proteins. By fractionation on sucrose density gradients, EPX/EDN localised in the specific granules as well as in a cytoplasmic extra-granular compartment of low equilibrium density that partially overlapped with vesicular structures, cytosolic proteins and plasma membranes. This compartment was clearly separate from the low density peak of ECP that increases during the pollen season. There were no significant differences in the amounts of EPX/EDN present in the low density peak of healthy and allergic subjects. Immuno-gold labelling electron microscopy showed EPX/EDN in specific granules, cytoplasm and associated to plasma membranes. In conclusion, substantial amounts of EPX/EDN localise in an extra-granular, low equilibrium density compartment of human eosinophils.

Reduced cystatin C-estimated GFR and increased creatinine-estimated GFR in comparison with iohexol-estimated GFR in a hyperthyroid patient: a case report.

INTRODUCTION: Estimation of the glomerular filtration rate (GFR) is essential for the evaluation of patients with kidney disease, and for treating patients with drugs that are eliminated from the circulation by the kidneys. Cystatin C has been shown to be superior to creatinine for estimating GFR in several studies. However, studies showing that thyroid function has an impact on cystatin C have not addressed the question of whether the changes in cystatin C levels are due to changes in GFR or in cystatin C synthesis. CASE PRESENTATION: We report an account of a hyperthyroid patient with a discrepancy between the GFR estimates from cystatin C and creatinine. The cystatin C concentration (1.36 mg/L) was higher and gave an estimated GFR which was lower (51 mL/min/1.73 m2), while the creatinine concentration was lower (36 mumol/L) and gave a corresponding creatinine-estimated GFR that was higher (145 mL/min/1.73 m2) than the iohexol-estimated GFR (121 mL/min/1.73 m2) during the hyperthyroid period. After thyroidectomy, the creatinine concentration was 36 mumol/L and creatinine-estimated GFR was calculated as 73 mL/min/1.73 m2, while the cystatin C concentration and cystatin C-calculated GFR was 0.78 mg/L and 114 mL/min/1.73 m2, respectively. CONCLUSION: In contrast to creatinine, cystatin C levels rose in the hyperthyroid state as compared to the euthyroid state. The cystatin C-estimated GFR was reduced compared to the iohexol-estimated GFR. This patient case shows that the hyperthyroid-associated changes in cystatin C levels are not due to changes in GFR. Thyroid function should thus be considered when both cystatin C and creatinine are used as markers of kidney function.

Specific granules of human eosinophils have lysosomal characteristics: presence of lysosome-associated membrane proteins and acidification upon cellular activation.

Eosinophils possess characteristic specific granules. Their content may be important during host defense but it can also cause damage after release at sites of inflammation. We investigated possible lysosomal characteristics of these granules. Lysosome-associated membrane protein (LAMP)-1 and 2, were detected by Western blot, subcellular fractionation, and immunoelectron microscopy (IEM) and were localized to the membrane of specific granules and in vesicles of the cytoplasm, separate from secretory vesicles. No binding of mannose 6-phosphate receptor to proteins of specific granules could be detected, indicating that they are dephosphorylated and mature. Cellular activation by interleukin-5 caused acidification of specific granules, as detected by pH-dependent probes. The acidification was inhibited by concanamycin A (inhibitor of vacuolar H(+)-ATPase). Activation of eosinophils by serum-treated zymosan (STZ) caused degranulation into STZ-containing phagosomes and incorporation of LAMPs to their membranes. In conclusion, specific granules of eosinophils can be regarded as specialized primary lysosomes, a feature that may be important for their function and integrity.