Anaphylactic transfusion reactions in haptoglobin-deficient patients with IgE and IgG haptoglobin antibodies

Identification and Diagnosis of Complete Haptoglobin Gene Deletion, One of the Genes Responsible for Adverse Posttransfusion Reactions

Allergic reactions are the most frequent adverse events in blood transfusion, and anaphylactic shock, although less frequent, is systemic and serious. The cause of allergic reactions to blood transfusions are largely unknown, but deficiencies in serum proteins such as haptoglobin (Hp) can lead to anaphylactic shock. A complete deletion of the haptoglobin gene (HPdel) was first identified in families with anomalous inheritance and then verified as a genetic variant that can cause anaphylactic shock because homozygotes for HPdel have complete Hp deficiency. Thereby, they may produce antibodies against Hp from blood transfusions. HPdel is found in East and Southeast Asian populations, with a frequency of approximately 0.9% to 4%, but not in other populations. Diagnosis of Hp deficiency due to HPdel prior to transfusion is advisable because severe adverse reactions can be prevented by washing the red blood cells and/or platelets with saline or by administering plasma products obtained from an Hp-deficient donor pool. This review outlines the background of the identification of HPdel and several genetic and immunological methods developed for diagnosing Hp deficiency caused by HPdel.

A novel reagent for the screening of haptoglobin-deficient blood donors

BACKGROUND AND OBJECTIVES

In Japan, the prevalence of haptoglobin deficiency is approximately 1 in 4000. Haptoglobin-deficient individuals may produce anti-haptoglobin from allo-immunization, leading to serious transfusion reactions. Therefore, implementation of a consistent supply of haptoglobin-deficient fresh frozen plasma is crucial. We developed a novel reagent to facilitate large-scale identification of haptoglobin-deficient individuals as potential donors of plasma products.

MATERIALS AND METHODS

We established mouse monoclonal anti-haptoglobin-producing cell lines (three clones) using the hybridoma method by immunizing mice with the haptoglobin protein. Purified antibodies were conjugated with carboxylate-modified polystyrene latex beads and used for haptoglobin measurements by the latex agglutination method using an automatic analyser (LABOSPECT008). Samples with low protein concentrations were re-examined by enzyme-linked immunosorbent assay to confirm the results. Additionally, the haptoglobin gene was amplified by polymerase chain reaction to confirm the haptoglobin deletion allele (Hpdel ).

RESULTS

From February to October 2022, 7476 blood donor samples were screened. Two haptoglobin-deficient and 21 low-haptoglobin-expressing individuals were identified. Two haptoglobin-deficient donors were found homozygous for Hpdel , and 19 (90%) of the 21 low-haptoglobin-expressing individuals were heterozygous for Hpdel , which includes the first reported case of heterozygous Hpdel /HpJohnson .

CONCLUSION

We developed a new reagent for the detection of haptoglobin deficiency, which is automatable and inexpensive and appears useful for large-scale screening of blood donors.

Do Children With an Allergic Transfusion Reaction Require Premedication For All Blood Products?

BACKGROUND

Children with a history of allergic transfusion reactions (ATRs) receive antihistamine premedication with or without hydrocortisone to prevent subsequent reactions. We aim to examine the frequency of developing ATRs to subsequent different blood product type transfusions.

METHODS

A retrospective chart review of children who received blood product transfusions (packed red blood cells, platelets, frozen plasma, intravenous immunoglobin, albumin, and cryoprecipitate) and developed ATRs. Cases were identified through Transfusion Transmitted Injuries Surveillance System- Ontario database with a complementary chart review. Demographics and subsequent transfusions records were described.

RESULTS

During this period, 35,925 blood products were transfused to 4153 patients. Thirty-eight ATRs were reported in 30 patients. All ATRs were minor except 1 anaphylaxis to albumin transfusion. Seven patients (23%) developed multiple ATRs, and all of them were of the same blood product type. A total of 60 subsequent different blood product types were transfused to the 7 patients who had multiple ATRs; none of those transfusions caused ATR.

CONCLUSION

In children with a history of ATR, developing a reaction to a different blood product type is rare. Hence, premedicating those transfusions is not warranted.

Blood Transfusion Components Inducing Severe Allergic Reactions: The First Case of Kounis Syndrome Induced by Platelet Transfusion

Kounis syndrome is a multisystem and multidisciplinary disease affecting the circulatory system that can be manifested as spasm and thrombosis. It can occur as allergic, hypersensitivity, anaphylactic, or anaphylactoid reactions associated with the release of inflammatory mediators from mast cells and from other interrelated and interacting inflammatory cells, including macrophages and lymphocytes. A platelet subset with high- and low-affinity IgE surface receptors is also involved in this process. Whereas the heart, and particularly the coronary arteries, constitute the primary targets of inflammatory mediators, the mesenteric, cerebral, and peripheral arteries are also vulnerable. Kounis syndrome is caused by a variety of factors, including drugs, foods, environmental exposure, clinical conditions, stent implantation, and vaccines. We report a unique case of a 60-year-old male with a past medical history of allergy to human albumin, alcoholic cirrhosis, and esophageal varices, who was admitted due to multiple episodes of hematemesis. Due to low hemoglobin levels, he was transfused with 3 units of red blood cells and fresh frozen plasma without any adverse reactions. On the third day of hospitalization, severe thrombocytopenia was observed and transfusion of platelets was initiated. Immediately following platelet infusion, the patient developed chest discomfort, skin signs of severe allergic reaction, and hemodynamic instability. The electrocardiogram revealed ST segment elevation in the inferior leads. Given the strong suspicion of Kounis syndrome/allergic coronary spasm, the patient was treated with anti-allergic treatment only, without any anti-platelet therapy. The clinical status of the patient gradually improved and the electrocardiographic changes reverted to normal. Based on these findings, Kounis hypersensitivity-associated acute coronary syndrome, specifically, type I Kounis syndrome, was diagnosed. Although platelet transfusion can be a life-saving therapy, each blood transfusion carries a substantial risk of adverse reactions. The aims of this report are to expand the existing knowledge of patient responses to blood transfusion and provide information on the incidence of various severe transfusion reactions to all blood components and especially to platelets. To the best of our knowledge, Kounis syndrome induced by platelet transfusionhas never been previously reported. Hypersensitivity to platelet external membrane glycoproteins in an atopic patient seems to be the possible etiology. Despite that Kounis syndrome remains an under-diagnosed clinical entity in everyday practice, it should always be considered in the differential diagnosis of acute coronary syndromes.

Duplex dual-labeled fluorescence probe-based melting curve and endpoint genotyping assays for genotyping of rs2000999 and haptoglobin gene deletion

Haptoglobin (Hp) is a hemoglobin-binding serum glycoprotein. Some variations in the Hp gene (HP) or Hp-related gene (HPR), including a single-nucleotide polymorphism in intron 2 of HRP, rs2000999, and a complete deletion of the HP gene (HP^{de l} ), one of the rare variants of HP, have been reported to correlate with the serum cholesterol concentration as well as the serum Hp concentration. In this study, we developed a duplex dual-labeled fluorescence probe-based method to simultaneously determine the rs2000999 G > A polymorphism by melting curve genotyping and the zygosity of HP^{de l} by endpoint genotyping. This method was then validated by using the genomic DNA from 94 Japanese subjects for whom genotypes of rs2000999 and HP^del zygosity had already been determined. The results obtained with this method were in perfect agreement with the previous ones. Thus, the present method enables us to estimate these two polymorphisms in relatively large-scale groups of subjects, especially in Asian populations where the HP^del is distributed.

Successful management of severe allergic reactions to platelet transfusion with omalizumab: A case report

RATIONALE

An allergic transfusion reaction is a common side effect of transfusions of red blood cells. Using washed red blood cells is the most effective method for preventing such a reaction. However, the availability of other washed transfusion components, including platelets, is limited.

PATIENT CONCERNS

A 69-year-old patient with acute myeloid leukemia progressed from myelodysplastic syndrome and was treated with azacitidine. She experienced a minor reaction to platelet transfusion that initially responded to the administration of corticosteroids and antihistamines. However, she worsened even after subsequent preventive treatments and was referred to the emergency department due to anaphylaxis. The patient developed hypotension, chest pain, and dyspnea 10 minutes after the initiation of platelet transfusion.

DIAGNOSES

She was diagnosed with platelet-induced anaphylaxis.

INTERVENTIONS

In an attempt to prevent anaphylaxis, 150 mg of omalizumab was prescribed 1 week prior to transfusion. However, she experienced anaphylaxis again and was administered intramuscular epinephrine. For the following transfusion, we treated her with a 300 mg dose of omalizumab 24 hours before the transfusion.

OUTCOMES

She tolerated well and continued to receive further chemotherapy and platelet transfusion with premedication.

LESSONS

This case suggests that omalizumab is a good candidate for the management of severe allergic transfusion reactions.

Preventing adverse reactions in pediatric transfusions using washed platelet concentrate

Blood transfusion is an important form of supportive care in children; however, transfusion-associated adverse reactions (TARs) are a problem. As with adults, allergic transfusion reactions (ATRs) and febrile non-hemolytic transfusion reactions (FNHTRs) are major TARs, and the frequency of ATRs caused by platelet concentrate (PC) tends to be particularly high. The plasma component of the blood product is thought to be a major factor in the onset of TARs such as ATR and FNHTR. By contrast, in children, age, underlying disease, and number of blood transfusions may be relevant patient-related factors. Although acetaminophen or diphenhydramine may be used prophylactically to prevent TARs, there is no clear evidence of their effectiveness. Volume-reduced PC is used to prevent TARs; however, it may be difficult to maintain the quality of platelets. Plasma-replaced PC stored with platelet additive solution raises the concern that TARs cannot be completely prevented by residual plasma. Washed PC removes most of the plasma, so it can effectively prevent ATR and FNHTR. The recent development of platelet additive solution [M-sol, bicarbonate Ringer's solution supplemented with acid-citrate-dextrose formula A (BRS-A)] in Japan has enabled the maintenance of the quality of platelets for long periods. The clinical use of washed PC in Japan has therefore progressed. Washed PC with M-sol or BRS-A for pediatric patients can effectively prevent TARs without diminishing the transfusion effect. The supply of washed PC has begun from the Japanese Red Cross Society, and it has become possible to use washed PC at all medical institutions in Japan.

Haptoglobin polymorphisms in Latin American populations

Several genetic polymorphisms of the haptoglobin gene (HP) or haptoglobin-related gene (HPR) were reported to show a population-specific distribution and to be associated with not only serum haptoglobin (HP) but also cholesterol levels. For such association studies, it is important to know the distribution of polymorphisms or their haplotypes in the populations concerned. However, no comprehensive genetic studies have explored this in Latin Americans, and not every human variation or genotype is available in a database. In this study, we determined the genotypes of common HP (HP¹ and HP²), HP^del, rs5471, rs5472, and rs2000999 in several Latin American populations. Haplotypes of rs5472-common HP-rs2000999 polymorphisms were estimated. We did not encounter any HP^del, and the frequencies of rs5471 A, rs5472 A, HP¹, and rs2000999 G were higher than their counterpart alleles in studied populations. All of the alleles with higher frequency in the Latin Americans are associated with higher serum HP and lower cholesterol levels. Both A-1-G (probably HP^1S) and G-1-G (probably HP^1F) haplotypes were higher in Latin American populations than those in other geographic regions. In addition, the genetic influx from populations of other continents into Peruvians seems to be relatively lower than that into other Latin Americans.

Haptoglobin: From hemoglobin scavenging to human health

Haptoglobin (Hp) belongs to the family of acute-phase plasma proteins and represents the most important plasma detoxifier of hemoglobin (Hb). The basic Hp molecule is a tetrameric protein built by two α/β dimers. Each Hp α/β dimer is encoded by a single gene and is synthesized as a single polypeptide. Following post-translational protease-dependent cleavage of the Hp polypeptide, the α and β chains are linked by disulfide bridge(s) to generate the mature Hp protein. As human Hp gene is characterized by two common Hp1 and Hp2 alleles, three major genotypes can result (i.e., Hp1-1, Hp2-1, and Hp2-2). Hp regulates Hb clearance from circulation by the macrophage-specific receptor CD163, thus preventing Hb-mediated severe consequences for health. Indeed, the antioxidant and Hb binding properties of Hp as well as its ability to stimulate cells of the monocyte/macrophage lineage and to modulate the helper T-cell type 1 and type 2 balance significantly associate with a variety of pathogenic disorders (e.g., infectious diseases, diabetes, cardiovascular diseases, and cancer). Alternative functions of the variants Hp1 and Hp2 have been reported, particularly in the susceptibility and protection against infectious (e.g., pulmonary tuberculosis, HIV, and malaria) and non-infectious (e.g., diabetes, cardiovascular diseases and obesity) diseases. Both high and low levels of Hp are indicative of clinical conditions: Hp plasma levels increase during infections, inflammation, and various malignant diseases, and decrease during malnutrition, hemolysis, hepatic disease, allergic reactions, and seizure disorders. Of note, the Hp:Hb complexes display heme-based reactivity; in fact, they bind several ferrous and ferric ligands, including O₂, CO, and NO, and display (pseudo-)enzymatic properties (e.g., NO and peroxynitrite detoxification). Here, genetic, biochemical, biomedical, and biotechnological aspects of Hp are reviewed.

Types of acute phase reactants and their importance in vaccination

Vaccines are considered to be one of the most cost-effective life-saving interventions in human history. The body's inflammatory response to vaccines has both desired effects (immune response), undesired effects [(acute phase reactions (APRs)] and trade-offs. Trade-offs are more potent immune responses which may be potentially difficult to separate from potent acute phase reactions. Thus, studying acute phase proteins (APPs) during vaccination may aid our understanding of APRs and homeostatic changes which can result from inflammatory responses. Depending on the severity of the response in humans, these reactions can be classified as major, moderate or minor. In this review, types of APPs and their importance in vaccination will be discussed.

A novel method for the laboratory workup of anaphylactic transfusion reactions in haptoglobin-deficient patients

BACKGROUND

Patients with congenital haptoglobin deficiency can develop anti-haptoglobin antibodies after exposure to blood products, and they can suffer from life-threatening anaphylactic transfusion reactions. Here, we present a case of a 57-year-old Chinese male with myelodysplastic syndrome who manifested an anaphylactic transfusion reaction during the transfusion of platelets. The only abnormality detected during his reaction laboratory workup was an undetectable haptoglobin level in the absence of evidence of hemolysis.

STUDY DESIGN AND METHODS

Surface plasmon resonance (SPR) was explored as a method to be able to detect the presence of anti-haptoglobin antibodies in serum. First, haptoglobin was immobilized to the surface of an SPR sensor chip. The patient's serum sample was injected, and the binding response was monitored in real time. Serum samples from five healthy volunteers were used as negative controls. Binding specificity was assessed in competition experiments using soluble haptoglobin. Anti-IgG, -IgA, -IgM, -IgD and -IgE antibodies were used to identify the antibody isotype.

RESULTS

An IgG anti-haptoglobin antibody was detected in the patient's serum with SPR.

CONCLUSION

SPR provided a rapid, readily available method for the detection of an IgG anti-haptoglobin antibody in an anhaptoglobinemic individual. This confirmed the underlying etiology of the anaphylactic nonhemolytic transfusion reaction and justified the necessity of stringently washed cellular products for all future transfusions and strong caution for future use of plasma-containing products.

Reduction in adverse transfusion reactions with increased use of washed platelet concentrates in Japan-A retrospective multicenter study

Plasma removal by washing platelet concentrates (PCs) is effective in preventing adverse reactions to PC transfusions. The Japanese Red Cross Society (JRCS) started releasing washed PCs (WPCs) as a commercially approved blood product in September 2016. This retrospective multicenter study investigated the change in the number of transfused WPCs and the impact on the incidence of adverse reactions to PCs before and after the release. The numbers and types of transfused PCs and the adverse reactions to the PCs for a year before the start of the WPC release and for a year after the release were reported by 27 medical institutes in Japan. Transfusion information for approximately 8% of the amount of PCs supplied in Japan was analyzed during the study period. After the start of WPC release by the JRCS, the number of transfused WPCs doubled. The rate of adverse reactions to PCs decreased significantly (p = 0.0223), from 4.30% before the release to 4.05% after the release. The rates of adverse reactions to unwashed and WPCs were 4.13% and 0.84%, respectively. Allergic adverse reactions were significantly decreased after the release (3.60% before versus 3.37% after). No severe allergic reactions to WPCs were reported. The release of WPCs by the JRCS significantly reduced transfusion-related adverse reactions to PCs in Japan.

Immunoglobulin (Ig)G antibodies against IgE identified by basophil activation test as the putative causative agent of a serious allergic transfusion reaction: potential utility of the test as a new safety measure for allergic transfusion reactions

BACKGROUND

In most cases of allergic transfusion reactions (ATRs), the causative agents have not been identified and the mechanisms are largely unknown, with a few exceptions. The basophil activation test (BAT) was recently introduced in the field of transfusion to investigate the causal relationships between ATRs and transfusion, as well as the mechanisms behind them.

STUDY DESIGN AND METHODS

The BAT was used to screen the residual supernatants (SNs) of 43 blood components associated with serious ATRs for those that can activate basophils of many healthy volunteers. The SNs were then fractionated by centrifugal ultrafiltration and protein G column chromatography and each separated fraction was reexamined by the BAT.

RESULTS

Of the 43 such blood components, one activated basophils from 19 of 21 healthy volunteers. In the blood component, the IgG antibody against IgE was identified as a putative causative agent.

CONCLUSION

Blood donors who possessed the IgG antibody against IgE may be dangerous to transfusion recipients. The BAT would be useful in identifying such high-risk blood donors, when it is used to screen the blood components associated with serious ATRs for residual SNs that can activate the basophils of many healthy volunteers.

Transfusion Reactions

Transfusion reactions are common occurrences, and clinicians who order or transfuse blood components need to be able to recognize adverse sequelae of transfusion. The differential diagnosis of any untoward clinical event should always consider adverse sequelae of transfusion, even when transfusion occurred weeks earlier. There is no pathognomonic sign or symptom that differentiates a transfusion reaction from other potential medical problems, so vigilance is required during and after transfusion when a patient presents with a change in clinical status. This review covers the presentation, mechanisms, and management of transfusion reactions that are commonly encountered, and those that can be life-threatening.

Clinical utility of the basophil activation test for analysis of allergic transfusion reactions: a pilot study

BACKGROUND AND OBJECTIVES

In previous studies, we demonstrated that the basophil-activating effects of supernatants found in residual-transfused platelet concentrates (PC-SNs) on whole blood basophils in cases of allergic transfusion reactions (ATRs) could be assessed by the basophil activation test (BAT) in terms of allergen/IgE dependency. However, in these studies, the basophils were derived from third-party healthy volunteers. In this study, we performed BAT using patients' own blood basophils to analyse ATRs.

MATERIALS AND METHODS

The BAT was performed in two cases of severe ATRs using residual PC-SNs and the patients' own basophils in the presence and absence of dasatinib, an inhibitor of IgE-mediated basophil activation.

RESULTS

In both cases, PC-SNs exhibited basophil-activating activity against the patients' basophils, but not against basophils from third-party healthy volunteers. In addition, basophil activation was inhibited in the presence of dasatinib, indicating that the basophils were activated in an allergen/IgE-dependent manner. Of note, the basophils in Case 2, but not in Case 1, were activated by PC-SNs from some unrelated non-haemolytic transfusion reaction cases.

CONCLUSION

This pilot study indicates that the BAT may be useful in clarifying the causal relationship between ATRs and transfused blood as well as in elucidating the mechanisms behind ATRs considering the allergen/IgE-dependent pathway.

Mitochondrial damage-associated molecular patterns as potential proinflammatory mediators in post-platelet transfusion adverse effects

BACKGROUND

Platelet concentrates (PCs) are the most common blood components eliciting nonhemolytic transfusion reactions (NHTRs), such as allergic transfusion reactions and febrile reactions. However, the precise mechanisms of NHTRs in PC transfusion remain largely unknown. Previous studies reported that mitochondria-derived damage-associated molecular patterns (DAMPs) could be important mediators of innate cell inflammation. Platelets (PLTs) represent a major reservoir of mitochondria in the blood circulation. The aim of this study was to determine the possible involvement of mitochondrial DAMPs in NHTRs.

STUDY DESIGN AND METHODS

The amount of mitochondrial DAMPs was determined as an index of total copy numbers of mitochondrial DNA (mtDNA), including mtDNA itself and free mitochondria, using quantitative real-time polymerase chain reaction. To examine whether neutrophils, monocytes, and basophils were activated by mitochondrial DAMPs in vitro, an in vitro whole blood cell culture assay was performed.

RESULTS

In blood components associated with NHTRs, the mean total mtDNA concentration was highest in PCs followed in order by fresh-frozen plasma and red blood cells. The amount of mtDNA in NHTR PCs was higher than that in control PCs without NHTRs. The mitochondrial DAMPs present in NHTR PCs was high enough to activate neutrophils, monocytes, and basophils, when costimulated with N-formyl-l-methionyl-l-leucyl-l-phenylalanine or HLA antibodies.

CONCLUSION

PLT-derived mitochondrial DAMPs are candidate risk factors for the onset of NHTRs.

Repeated exposure rather than the total volume of transfused components may influence the incidence of allergic transfusion reactions

BACKGROUND

The plasma fraction of blood components has an essential role in the etiology of allergic transfusion reactions (ATRs). The difference of incidences of ATRs between fresh-frozen plasma (FFP) and platelet concentrates (PCs), in which plasma is the main component, is not clearly understood. This study compares the frequency of ATRs to FFP versus PCs on both first and subsequent (nonfirst) transfusions and considers the factors influencing the risk of ATRs.

STUDY DESIGN AND METHODS

Five hospitals agreed to systematically collect and share 2 years of data (January 2010 through December 2011). This was a retrospective observational analysis of data including the number of transfusion episodes and ATRs for FFP and PCs on first-transfusion patients (without transfusion history) and previously transfused patients.

RESULTS

The incidence of ATRs to PCs (2.51%) was significantly higher than to FFP (1.68%) on subsequent transfusions (p < 0.001). On the other hand, there were no significant differences in the incidences of ATRs to FFP (2.67%) and PCs (2.82%) on first transfusions. This discrepancy was most pronounced among males: FFP versus PCs on first transfusions, 2.02% versus 2.60% (p = 0.30); and on subsequent transfusions, 1.58% versus 2.46% (p = 0.0007). Among females, FFP versus PCs on first transfusions was 3.59% versus 3.13% (p = 0.61) and on subsequent transfusions was 1.87% versus 2.61% (p = 0.029).

CONCLUSION

Repeated exposure rather than the total volume of transfused components may influence the incidence of ATRs.

Adverse events related to blood transfusion

The acute blood transfusion reactions are responsible for causing most serious adverse events. Awareness about various clinical features of acute and delayed transfusion reactions with an ability to assess the serious reactions on time can lead to a better prognosis. Evidence-based medicine has changed today's scenario of clinical practice to decrease adverse transfusion reactions. New evidence-based algorithms of transfusion and improved haemovigilance lead to avoidance of unnecessary transfusions perioperatively. The recognition of adverse events under anaesthesia is always challenging. The unnecessary blood transfusions can be avoided with better blood conservation techniques during surgery and with anaesthesia techniques that reduce blood loss. Better and newer blood screening methods have decreased the infectious complications to almost negligible levels. With universal leukoreduction of red blood cells (RBCs), selection of potential donors such as use of male donors only plasma and restriction of RBC storage, most of the non-infectious complications can be avoided.

Transfusion and component characteristics are not associated with allergic transfusion reactions to apheresis platelets

BACKGROUND

Transfusion-related characteristics have been hypothesized to cause allergic transfusion reactions (ATRs) but they have not been thoroughly studied. The primary objective of this study is to evaluate the associations of infusion rate, infusion volume, ABO mismatching, component age, and pretransfusion medication with the incidence and severity of ATRs. A secondary objective is to compare the risk of these attributes relative to the previously reported risk factor for aeroallergen sensitization in transfusion recipients, as measured by an aeroallergen-specific immunoglobulin (Ig)E antibody screen.

STUDY DESIGN AND METHODS

Clinical and transfusion-related data were collected on subjects with reported ATRs and uneventful (control) apheresis platelet (PLT) transfusions over a combined 21-month period at two academic medical centers. Control transfusions were selected as the next uneventful transfusion after an ATR was reported. Logistic regression, Mann-Whitney, and t tests were used to assess associations with ATRs. Previously reported aeroallergen-specific IgE screening data were incorporated into a multivariable logistic regression.

RESULTS

A total of 143 ATRs and 61 control transfusions were evaluated among 168 subjects, ages 2 to 86 years. Infusion rate, infusion volume, ABO mismatching, component age, and pretransfusion medication showed no significant association with ATRs (p > 0.05). Neither infusion rate nor infusion volume increased the risk of anaphylaxis versus mucocutaneous-only ATRs. Aeroallergen sensitization has previously been associated with ATRs. After transfusion-related covariates were controlled for, aeroallergen sensitization remained significantly associated with ATRs (odds ratio, 2.68; 95% confidence interval, 1.26-5.69).

CONCLUSIONS

Transfusion- and component-specific attributes are not associated with ATRs. An allergic predisposition in transfusion recipients is associated most strongly with ATR risk.

Unexpected reactions of the anti-IgA antibody particle gel immunoassay

BACKGROUND

The cause of allergic transfusion reactions remains often unknown, but in rare cases anti-immunoglobulin A (IgA) antibodies in patients with IgA-deficiency can be found. We report on the use of the DiaMed particle gel immunoassay (PaGIA) for detection of anti-IgA antibodies in patients with allergic transfusion reactions.

METHODS

The examination of the suspected adverse reactions included an anti-IgA antibody test (ID-PaGIA Anti-IgA antibody test; DiaMed GmbH, Cressier , Switzerland) and measurement of IgA concentration in the patient's plasma. In the case of a discrepancy IgA subclasses were examined and neutralization of the anti-IgA antibodies by pure IgA was performed.

RESULTS

Of 142 patients tested for IgA concentration and anti-IgA antibodies, 8 gave positive results for the anti-IgA antibody test. In seven of these cases (4.9% of the patients tested) IgA levels were found to be normal, and in four of five so tested, the positive result could not be neutralized with purified IgA. Only one patient had confirmed IgA deficiency with anti-IgA antibodies that were neutralized by addition of purified IgA.

CONCLUSION

Cause and clinical relevance of a positive reaction of the anti-IgA antibody test in patients with normal total IgA and normal IgA subclasses remains unknown. Because of the high false positive rate we do not recommend this test as a screening test for anti-IgA antibodies when evaluating allergic transfusion reactions, but instead recommend measurement of total IgA in patient's plasma or serum as a primary screen for IgA deficiency with antibodies as a cause of allergic transfusion reaction.

The impact of platelet additive solution apheresis platelets on allergic transfusion reactions and corrected count increment (CME)

BACKGROUND

Allergic transfusion reaction (ATR) incidence ranges from 1% to 3% of all transfusions. We evaluated the impact of InterSol platelet additive solution (PAS) apheresis platelets (APs) on the incidence of ATRs and the posttransfusion platelet (PLT) increment.

STUDY DESIGN AND METHODS

This retrospective study evaluated all ATRs among patients at a university hospital that maintained a mixed inventory of PAS APs and non-PAS APs (standard plasma-suspended PLTs). Corrected count increments (CCIs) were calculated for AP transfusions of individuals who received both a PAS and a non-PAS AP transfusion within a 7-day period. Hypothesis testing was performed with chi-square test for dichotomous variables and t tests for continuous variables.

RESULTS

The incidence of ATRs among the non-PAS APs was 1.85% (72 ATRs/3884 transfusions) and 1.01% (12 ATRs/1194 transfusions) for PAS APs (risk ratio [RR], 0.54; 95% confidence interval [CI]=0.30-0.99; p=0.04). However, there was no difference in the incidence of febrile nonhemolytic transfusion reactions between non-PAS APs (incidence, 0.70%; 27/3884) compared to PAS APs (incidence, 0.59%; 7/1194; p=0.69). Among 223 individuals with paired non-PAS and PAS AP transfusions, the mean CCI at 1 to 4 hours after transfusion was 4932 (95% CI, 4452-5412) for non-PAS APs and was lower for PAS APs (CCI, 3766; 95% CI, 3375-4158; p ≤ 0.001). However, there was no significant difference in mean CCI at 12 to 24 hours between non-PAS (CCI, 2135; 95% CI, 1696-2573) and PAS APs (CCI, 1745; 95% CI, 1272-2217; p=0.14).

CONCLUSIONS

PAS APs substantially reduce the number of ATRs. CCIs for PAS APs were lower immediately after transfusion, but not significantly different at 12 to 24 hours.

Transfusion complications in thalassemia patients: a report from the Centers for Disease Control and Prevention (CME)

BACKGROUND

Transfusions are the primary therapy for thalassemia but have significant cumulative risks. In 2004, the Centers for Disease Control and Prevention (CDC) established a national blood safety monitoring program for thalassemia. This report summarizes the population and their previous nonimmune and immune transfusion complications.

STUDY DESIGN AND METHODS

The CDC Thalassemia Blood Safety Network is a consortium of centers longitudinally following patients. Enrollment occurred from 2004 through 2012. Demographics, transfusion history, infectious exposures, and transfusion and nontransfusion complications were summarized. Logistic regression analyses of factors associated with allo- and autoimmunization were employed.

RESULTS

The race/ethnicity of these 407 thalassemia patients was predominantly Asian or Caucasian. The mean ± SD age was 22.3 ± 13.2 years and patients had received a mean ± SD total number of 149 ± 103.4 units of red blood cells (RBCs). Multiorgan dysfunction was common despite chelation. Twenty-four percent of transfused patients had previous exposure to possible transfusion-associated pathogens including one case of babesia. As 27% were immigrants, the infection source cannot be unequivocally linked to transfusion. Transfusion reactions occurred in 48%, including allergic, febrile, and hemolytic; 19% were alloimmunized. Common antigens were E, Kell, and C. Years of transfusion was the strongest predictor of alloimmunization. Autoantibodies occurred in 6.5% and were associated with alloimmunization (p < 0.0001). Local institutional policies, not patient characteristics, were major determinants of blood preparation and transfusion practices.

CONCLUSION

Hemosiderosis, transfusion reactions, and infections continue to be major problems in thalassemia. New pathogens were noted. National guidelines for RBC phenotyping and preparation are needed to decrease transfusion-related morbidity.

Approach of using established and new laboratory tests to more comprehensively investigate noninfectious and nonhemolytic transfusion reactions--along with the experience in Japan

BACKGROUND AND OBJECTIVES

Noninfectious and nonhaemolytic transfusion reactions are the most common type of transfusion reactions. Several new tests have been made, helping diagnosis and understanding of their pathogenesis. This manuscript provides a review of the literature on currently available tests in association with the approach in Japan.

MATERIALS & METHODS

Primarily by using key words, more than 100 pertinent articles in the Medline database were identified and reviewed.

RESULTS

Numbers of laboratory tests are available including those for plasma protein levels, plasma protein antibodies, leucocyte and platelet antibodies, serum N-terminal-pro-brain natriuretic peptide levels, serum tryptase levels and genetic microchimerism. Cross-match tests, such as basophil activation test and neutrophil activation test, are also available to determine a causal relationship between the reaction and transfusion.

CONCLUSIONS

Several tests should help to confirm diagnosis and determine causal relationship between adverse reactions and transfusion and to gain an insight into the mechanism of the reaction in some cases, although some of the recently developed tests have not been completely validated.

IgE- and IgG mediated severe anaphylactic platelet transfusion reaction in a known case of cerebral malaria

Background:

Allergic reactions occur commonly in transfusion practice. However, severe anaphylactic reactions are rare; anti-IgA (IgA: Immunoglobulin A) in IgA-deficient patients is one of the well-illustrated and reported causes for such reactions. However, IgE-mediated hypersensitivity reaction through blood component transfusion may be caused in parasitic hyperimmunization for IgG and IgE antibodies.

Case Report:

We have evaluated here a severe anaphylactic transfusion reaction retrospectively in an 18year-old male, a known case of cerebral malaria, developed after platelet transfusions. The examination and investigations revealed classical signs and symptoms of anaphylaxis along with a significant rise in the serum IgE antibody level and IgG by hemagglutination method. Initial mild allergic reaction was followed by severe anaphylactic reaction after the second transfusion of platelets.

Conclusion:

Based on these results, screening of patients and donors with mild allergic reactions to IgE antibodies may help in understanding the pathogenesis as well as in planning for preventive desensitization and measures for safe transfusion.

A review of haptoglobin typing methods for disease association study and preventing anaphylactic transfusion reaction

Haptoglobin, the product of the Hp gene, is a glycoprotein involved in the scavenging of free hemoglobin. Haptoglobin levels increase or decrease in response to various acquired conditions, and they are also influenced by genetic predisposition. There were 2 major alleles, Hp (1) and Hp (2), and 1 minor allele, Hp (del) . Many researchers have attempted to study the haptoglobin types and their association with disease; however, no definitive conclusions have been reached yet. It is reported that patients who are genetically deficient in haptoglobin are at risk of anaphylaxis against blood components containing haptoglobin. Haptoglobin genotypes also affect the reference intervals of haptoglobin levels. Many studies have attempted to establish simple and accurate typing methods. In this paper, we have broadly reviewed several methods for haptoglobin typing-phenotyping, Southern blotting, conventional PCR, real-time PCR, and loop-mediated isothermal amplification. We discuss their characteristics, clinical applications, and limitations. The phenotyping methods are time consuming and labor intensive and not designed to detect patients harboring Hp (del) . The rapid and robust haptoglobin genotyping may help in preventing fatal anaphylactic reactions and in establishing the relationships between the haptoglobin phenotypes and diseases.

Current understanding of allergic transfusion reactions: incidence, pathogenesis, laboratory tests, prevention and treatment

Non-haemolytic transfusion reactions are the most common type of transfusion reaction and include transfusion-related acute lung injury, transfusion-associated circulatory overload, allergic reactions, febrile reactions, post-transfusion purpura and graft-versus- host disease. Although life-threatening anaphylaxis occurs rarely, allergic reactions occur most frequently. If possible, even mild transfusion reactions should be avoided because they add to patients' existing suffering. During the last decade, several new discoveries have been made in the field of allergic diseases and transfusion medicine. First, mast cells are not the only cells that are key players in allergic diseases, particularly in the murine immune system. Second, it has been suggested that immunologically active undigested or digested food allergens in a donor's blood may be transferred to a recipient who is allergic to these antigens, causing anaphylaxis. Third, washed platelets have been shown to be effective for preventing allergic transfusion reactions, although substantial numbers of platelets are lost during washing procedures, and platelet recovery after transfusion may not be equivalent to that with unwashed platelets. This review describes allergic transfusion reactions, including the above-mentioned points, and focusses on their incidence, pathogenesis, laboratory tests, prevention and treatment.

Scratching the surface of allergic transfusion reactions

Allergic transfusion reactions (ATRs) are a spectrum of hypersensitivity reactions that are the most common adverse reaction to platelets and plasma, occurring in up to 2% of transfusions. Despite the ubiquity of these reactions, little is known about their mechanism. In a small subset of severe reactions, specific antibody has been implicated as causal, although this mechanism does not explain all ATRs. Evidence suggests that donor, product, and recipient factors are involved, and it is possible that many ATRs are multifactorial. Further understanding of the mechanisms of ATRs is necessary so that rationally designed and cost-effective prevention measures can be developed.

Adverse effects of plasma transfusion

Plasma utilization has increased over the past two decades, and there is a growing concern that many plasma transfusions are inappropriate. Plasma transfusion is not without risk, and certain complications are more likely with plasma than other blood components. Clinical and laboratory investigations of the patients suffering reactions after infusion of fresh-frozen plasma (FFP) define the etiology and pathogenesis of the panoply of adverse effects. We review here the pathogenesis, diagnosis, and management of the risks associated with plasma transfusion. Risks commonly associated with FFP include: 1) transfusion-related acute lung injury, 2) transfusion-associated circulatory overload, and 3) allergic and/or anaphylactic reactions. Other less common risks include 1) transmission of infections, 2) febrile nonhemolytic transfusion reactions, 3) red blood cell alloimmunization, and 4) hemolytic transfusion reactions. The effects of pathogen inactivation or reduction methods on these risks are also discussed. Fortunately, a majority of the adverse effects are not lethal and are adequately treated in clinical practice.

Risks of transfusion

Each year, more than 4 million patients receive a blood transfusion in the United States to control symptoms associated with anemia, coagulopathy, thrombocytopenia, or some combination thereof. In each of these cases, the physician and the patient must weigh the potential benefits of the transfusion along with the associated risks. To assess accurately the risk:benefit ratio and to discuss this with the patient, the physician must be familiar with the range of adverse transfusion outcomes and the current estimates of their frequency. Most important, during the past decade the risk profile of transfusion has changed significantly. Transfusion-transmitted disease, although still a rare outcome of transfusion, is no longer an overriding concern in transfusion safety considerations; however, risks such as hemolysis, transfusion-related lung injury, and anaphylaxis continue to represent significant concerns and are relatively more common than the transmission of infectious diseases after transfusion. Against this background, the development of a national hemovigilance system, designed to evaluate more accurately transfusion adverse outcomes in the United States, will require greater precision and reliability in the assessment of adverse transfusion outcomes by clinicians if the proposed benefits of this system are to be realized.

Allergic agonists in apheresis platelet products are associated with allergic transfusion reactions

BACKGROUND

The mechanisms that underlie allergic transfusion reactions (ATRs) are not well characterized, but likely involve recipient, donor, and product factors. To assess product factors associated with ATRs, we investigated candidate mediators in apheresis platelet (PLT) products associated with ATRs and controls.

STUDY DESIGN AND METHODS

Using bead-based and standard enzyme-linked immunosorbent assays, we tested supernatants from 20 consecutive apheresis PLT transfusions associated with ATRs and 30 control products for concentrations of mediators in three categories: acute inflammatory mediators, direct agonists of basophils and mast cells, and growth and/or priming factors of basophils and mast cells.

RESULTS

Median concentrations of the direct allergic agonists C5a, brain-derived neurotrophic factor (BDNF), and CCL5 (RANTES) were 16.6, 41.8, and 13.9% higher, respectively, in the supernatant of apheresis PLT products that were most strongly associated with ATRs (p < 0.05 for each mediator). Other direct agonists (macrophage inflammatory protein-1α, monocyte chemotactic protein-1, eotaxin-1, interleukin-8) were similar between groups. Concentrations of acute inflammatory mediators and basophil growth and/or priming factors were also similar between groups (p > 0.2 for all associations).

CONCLUSION

The allergic agonists C5a, BDNF, and CCL5 may be mediators of ATRs in apheresis PLT products. Acute inflammatory proteins and basophil and/or mast cell growth and priming factors do not appear to be associated with apheresis PLT products that cause ATRs.

Atopic predisposition of recipients in allergic transfusion reactions to apheresis platelets

BACKGROUND

The biologic mechanisms of allergic transfusion reactions (ATRs) are largely unknown. We sought to compare the atopic predisposition of platelet (PLT) recipients who experienced an ATR to nonreactive control recipients.

STUDY DESIGN AND METHODS

We identified 37 consecutive apheresis PLT recipients who experienced an ATR and 26 matched controls. Total immunoglobulin (Ig)E and aero- and food allergen-specific IgE were quantified in plasma by a blood test for allergies (ImmunoCAP: Phadiatop and Fx5). IgE testing of apheresis PLT supernatants was also performed.

RESULTS

Pruritus and urticaria were manifest in 91.9 and 83.8% of all ATRs, with more severe respiratory symptoms and angioedema occurring in less than 15% of cases. No subject had anaphylaxis. Sex, age, and primary diagnosis were balanced between the two groups. Total and aeroallergen-specific IgE was higher among subjects experiencing an ATR in comparison to control subjects (median total IgE, 55.5 kU/L vs. 8.3 kU/L, p = 0.002; and median aeroallergen-specific IgE, 0.57 kUa/L vs. 0.36 kUa/L, p = 0.046). IgE antibody levels in apheresis products associated with ATRs were similar to control products (p > 0.1 for all IgE tests).

CONCLUSION

Recipient atopic predisposition, as defined by IgE sensitization, is a risk factor associated with ATRs.