Anna L. Peters

Glucose-6-phosphate Dehydrogenase Deficiency and Malaria: Cytochemical Detection of Heterozygous G6PD Deficiency in Women

Glucose-6-phosphate dehydrogenase (G6PD) deficiency is a X-chromosomally transmitted disorder of the erythrocyte that affects 400 million people worldwide. Diagnosis of heterozygously-deficient women is complicated: as a result of lyonization, these women have a normal and a G6PD-deficient population of erythrocytes. The cytochemical assay is the only reliable assay to discriminate between heterozygously-deficient women and non-deficient women or homozygously-deficient women. G6PD deficiency is mainly found in areas where malaria is or has been endemic. In these areas, malaria is treated with drugs that can cause (severe) hemolysis in G6PD-deficient individuals. A cheap and reliable test is necessary for diagnosing the deficiency to prevent hemolytic disorders when treating malaria. In this review, it is concluded that the use of two different tests for diagnosing men and women is the ideal approach to detect G6PD deficiency. The fluorescent spot test is inexpensive and easy to perform but only reliable for discriminating hemizygous G6PD-deficient men from non-deficient men. For women, the cytochemical assay is recommended. However, this assay is more expensive and difficult to perform and should be simplified into a kit for use in developing countries.

Glucose-6-phosphate dehydrogenase activity decreases during storage of leukoreduced red blood cells

During storage, the activity of the red blood cell (RBC) antioxidant system decreases. Glucose‐6‐phosphate dehydrogenase (G6PD) is essential for protection against oxidative stress by producing NADPH. G6PD function of RBC transfusion products is reported to remain stable during storage, but activity was measured in hemolysates and not in individual RBCs. We hypothesized that analysis of G6PD activity in individual RBC identifies storage‐dependent changes in G6PD function.

Redefining transfusion-related acute lung injury: don't throw the baby out with the bathwater

Recently two articles have been published in TRANSFUSION in which the authors propose to change the current definition on transfusion‐related acute lung injury (TRALI). It was proposed to view TRALI from the perspective of detectability versus nondetectability of leukoreactive alloantibodies (Transfusion 2015;55:1128‐34). The authors argue that only cases in which leukoreactive alloantibodies can be detected should be defined as “true” TRALI in analogy with the understanding of the pathophysiology of heparin‐induced thrombocytopenia. In the other article (Transfusion 2015;55:947‐52), the authors propose to redefine possible TRALI to transfused acute respiratory distress syndrome (ARDS) as their study in intensive care unit patients did not show a relation between the number of transfusions and possible TRALI.We discuss these two propositions in light of the current evidence on pathophysiology of TRALI and possible TRALI. We argue that it is too early to redefine TRALI, as 1) factors, such as storage time of platelets, which induce TRALI in preclinical studies, have not yet been properly investigated in humans. Further research is needed on these agents before it is concluded that antibody‐mediated TRALI is the only “true” TRALI. 2) In light of the current knowledge, it makes perfect sense that multiple transfusion is not related to possible TRALI: ARDS risk factors in these patients result in a very sensitive equilibrium in which even only one transfusion induces TRALI. Excluding possible TRALI from the TRALI definition would result in further underrecognition of TRALI induced by alloantibodies and interferes with exclusion of donors related to TRALI cases and thus TRALI prevention.

Transfusion of 35-day stored red blood cells does not result in increase of plasma non-transferrin bound iron in human endotoxemia.

Transfusion of a single unit of stored red blood cells (RBCs) has been hypothesized to induce supra‐physiological levels of non‐transferrin bound iron (NTBI), which may enhance inflammation and act as a nutrient for bacteria. We investigated the relation between RBC storage time and iron levels in a clinically relevant “two‐hit” human transfusion model.

Non‐polar lipids accumulate during storage of transfusion products and do not contribute to the onset of transfusion‐related acute lung injury

The accumulation of non‐polar lipids arachidonic acid, 5‐hydroxyeicosatetraenoic acid (HETE), 12‐HETE and 15‐HETE during storage of transfusion products may play a role in the onset of transfusion‐related acute lung injury (TRALI), a syndrome of respiratory distress after transfusion.

Transfusion of 35-day-stored red blood cells does not alter lipopolysaccharide tolerance during human endotoxemia: STORAGE TRIM

Transfusion‐related immunomodulation (TRIM) encompasses immunosuppressive and proinflammatory effects induced by red blood cell (RBC) transfusion. Changes that occur during storage in the RBC product have been hypothesized to underlie TRIM, mediated by tolerance of toll‐like receptors (TLR). We investigated whether transfusion of 35‐day‐stored autologous RBCs alters cytokine production in response to stimulation with lipopolysaccharide (LPS) or lipotheic acid (LTA), in a clinically relevant model of endotoxemia.

The practice of platelet transfusion prior to central venous catheterization in presence of coagulopathy: a national survey among clinicians

Correction of coagulopathy prior to central venous catheter (CVC) placement is advocated by guidelines, while retrospective studies support restrictive use of transfusion products.

Comparison of Spectrophotometry, Chromate Inhibition, and Cytofluorometry Versus Gene Sequencing for Detection of Heterozygously Glucose-6-Phosphate Dehydrogenase-Deficient Females

Glucose-6-phosphate dehydrogenase (G6PD) deficiency is the most common enzyme deficiency worldwide. Detection of heterozygously deficient females can be difficult as residual activity in G6PD-sufficient red blood cells (RBCs) can mask deficiency. In this study, we compared accuracy of 4 methods for detection of G6PD deficiency in females. Blood samples from females more than 3 months of age were used for spectrophotometric measurement of G6PD activity and for determination of the percentage G6PD-negative RBCs by cytofluorometry. An additional sample from females suspected to have G6PD deficiency based on the spectrophotometric G6PD activity was used for measuring chromate inhibition and sequencing of the G6PD gene. Of 165 included females, 114 were suspected to have heterozygous deficiency. From 75 females, an extra sample was obtained. In this group, mutation analysis detected 27 heterozygously deficient females. The sensitivity of spectrophotometry, cytofluorometry, and chromate inhibition was calculated to be 0.52 (confidence interval [CI]: 0.32–0.71), 0.85 (CI: 0.66–0.96), and 0.96 (CI: 0.71–1.00, respectively, and the specificity was 1.00 (CI: 0.93–1.00), 0.88 (CI: 0.75–0.95), and 0.98 (CI: 0.89–1.00), respectively. Heterozygously G6PD-deficient females with a larger percentage of G6PD-sufficient RBCs are missed by routine methods measuring total G6PD activity. However, the majority of these females can be detected with both chromate inhibition and cytofluorometry.

Volatile organic compounds in exhaled breath are independent of systemic inflammatory syndrome caused by intravenous lipopolysaccharide infusion in humans: results from an experiment in healthy volunteers

Systemic inflammatory response syndrome (SIRS) is observed during critical illness in most patients. It is defined by a clinical definition. The composition of volatile organic compounds (VOCs) in exhaled breath may change during SIRS and may thus serve as a diagnostic tool. We investigated whether exhaled breath VOCs can serve as biomarker for SIRS in a human model of endotoxemia. Eighteen healthy volunteers received 2 ng Eschericia coli lipopolysaccharide (LPS) kg-1 body weight intravenously. Venous blood and exhaled breath were collected before infusion of LPS and every 2 h thereafter, up to 8 h after infusion. The interleukin (IL)-6 concentration was measured in plasma. VOCs in the exhaled breath were measured by gas chromatography and mass spectrometry. A mixed effects model was fitted to examine the relation between the measured compounds in exhaled breath and time after LPS infusion or IL-6 levels in plasma. Partially-least squares discriminant analysis (PLS-DA) was used to investigate whether we could discriminate between samples collected before and after LPS infusion. The exhaled concentrations of 3-methyl-pentane, 4-methyl-pentanol, 1-hexanol, 2,4-dimethyl-heptane, decane and one unknown compound changed after LPS infusion. However, the false-discovery rate was 43% for the total set of 52 compounds that were present in all samples. Of these VOCs only the unknown compound was associated with systemic levels of IL-6. The PLS-DA algorithm resulted in a moderate discriminatory accuracy. SIRS induced by endotoxemia in human volunteers resulted in minor changes in exhaled VOCs. We therefore conclude that LPS infusion in healthy volunteers does not induce metabolic effects that can be detected through VOC analysis of the exhaled breath. This trial is registered at the Dutch Trial Register: NTR4455.

The practice of diagnosing and reporting transfusion-associated circulatory overload: a national survey among physicians and haemovigilance officers: The practice of reporting TACO

This study aims at identifying factors that disciplines consider when diagnosing and reporting transfusion‐associated circulatory overload (‘TACO’).