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

Allergic transfusion reactions to platelets are associated more with recipient and donor factors than with product attributes

BACKGROUND

Mechanisms of allergic transfusion reactions (ATRs) are not well understood. The aim of this study was to distinguish recipient-, donor-, and product-specific factors associated with ATRs.

STUDY DESIGN AND METHODS

We conducted a retrospective cohort study of apheresis platelet (AP) products transfused from April 2000 through March 2010. The concordance rate of ATRs when split AP products were transfused to at least two individuals was compared to the overall ATR rate among all AP products. Per-person ATR rates also were compared to the overall ATR rate.

RESULTS

We observed 1616 ATRs among 93,737 transfusions, for an overall incidence of 1.72% (95% confidence interval [CI], 1.64%-1.81%). Of the 1616 ATRs, 630 occurred when split AP products were transfused to at least two recipients. Of these 630 AP products, ATRs were observed in at least two different recipients of the same AP collection only 6 of 630 times, for a concordant incidence of 0.95% (95% CI, 0.35%-2.06%), which is similar to the overall ATR rate (p = 0.17). On an individual level, 30.0% of recipients had ATR rates of more than 5%, and these 30.0% accounted for 62.1% of ATRs. Donors of AP products associated with concordant ATRs donated AP products that had an ATR rate of 5.8% (95% CI, 3.1%-9.7%), which is higher than the overall ATR rate (p < 0.001).

CONCLUSIONS

An observed ATR does not predict an ATR in a different recipient of a split AP product. A minority of platelet recipients accounts for the majority of ATRs. Some donors are strongly associated with ATRs. Consequently, recipient and donor factors are implicated in the mechanism of ATRs.

Allergic transfusion reactions from blood components donated by IgA-deficient donors with and without anti-IgA: a comparative retrospective study

BACKGROUND AND OBJECTIVES

IgA deficiency is common (1/500) and up to 40% of affected individuals will develop anti-IgA. A few studies suggested that passive transfusion of anti-IgA was not associated with an increased risk of allergic reactions. This study was designed to assess the safety of transfusing blood components containing anti-IgA.

MATERIALS AND METHODS

IgA-deficient blood donors with and without anti-IgA were identified from Héma-Québec's (HQ) computerized database. IgA deficiency was confirmed by an ELISA method and the presence of anti-IgA by a passive hemagglutination assay. Blood donations from IgA-deficient donors issued to hospitals between March 1999 and December 2004 were retrieved. Medical charts of recipients were reviewed for the occurrence of a suspected transfusion reaction. Presence and nature of transfusion reactions were assessed blindly by an adjudicating committee.

RESULTS

A total of 323 IgA-deficient blood products were issued by HQ to 55 hospitals. Of these, 48 agreed to participate [315 blood products (97.5%)]. A total of 272 products were transfused: 174 contained anti-IgA, and 98 did not. Only two minor allergic reactions occurred in each group. Incidence of allergic reactions was 1.15% in the anti-IgA group and 2.04% in the group without anti-IgA (P = 0.91). There was no anaphylactic reaction in either group.

CONCLUSIONS

This study indicates that the proportion of allergic reactions does not appear to be greater in recipients of blood components containing anti-IgA compared to recipients of non-anti-IgA-containing components. Allowing donations from IgA-deficient donors with anti-IgA may therefore be contemplated.

Recent advances in laboratory assays for nonhemolytic transfusion reactions

Nonhemolytic transfusion reactions (NHTRs) are the most common transfusion reactions and include transfusion-related acute lung injury (TRALI) and allergic and febrile reactions. White blood cell (WBC) antibodies (Abs) against human leukocyte antigen (HLA) and human neutrophil antigen (HNA) in blood components are frequently implicated in NHTRs, especially in TRALI. Recently, we established a five-cell-lineage immunofluorescence test, a modified granulocyte immunofluorescence test, and a panel of cell lines stably expressing HNAs for efficient detection of Abs against well-known HNA-1 to HNA-5, and also Abs against neutrophil antigens other than HNA-1 to HNA-5. Using these techniques, we found that most of the non-HLA WBC Abs detected in NHTR cases were against antigens other than HNA-1 to HNA-5. In addition, using our newly established neutrophil activation test, which assesses neutrophil activation elicited by immunologic stimuli such as WBC Abs and immune complex, we found that heparin-binding protein is a potential final effector molecule that induces NHTRs, including TRALI. More recently, we reported that the basophil activation test, which was originally developed to identify allergens in the field of allergic diseases, might be useful in transfusion medicine. In this review, we summarize these new techniques and other related tests.

Pulmonary transfusion reactions

BACKGROUND

In recent years, pulmonary transfusion reactions have gained increasing importance as serious adverse transfusion events.

METHODS

Review of the literature.

RESULTS

Pulmonary transfusion reactions are not extremely rare and, according to hemovigilance data, important causes of transfusion-induced major morbidity and death. They can be classified as primary with predominant pulmonary injury and secondary as part of another transfusion reaction. Primary reactions include transfusion-related acute lung injury (TRALI), transfusion-associated circulatory overload (TACO) and transfusion-associated dyspnea (TAD). Secondary pulmonary reactions are often observed in the wake of hemolytic transfusion reactions, hypotensive/anaphylactic reactions, and transfusion-transmitted bacterial infections.

CONCLUSION

Knowledge and careful management of cases of pulmonary transfusion reactions are essential for correct reporting to blood services and hemovigilance systems. Careful differentiation between TRALI and TACO is important for taking adequate preventive measures.

Reactions Induced by Platelet Transfusions

SUMMARY: Platelet transfusions play a central role in therapeutic regimens for patients with hematologic/oncologic diseases who develop severe thrombocytopenia either in the course of their disease or following cytostatic therapy. Like other blood components, platelet transfusions have achieved a high degree of safety as far as transmission of viral diseases is concerned. However, transfusion of platelet concentrates is accompanied by a high frequency of febrile and anaphylactoid reactions. In rare cases, recipients of platelet concentrates are threatened by severe reactions as septic complications due to bacterial contamination of platelet concentrates, transfusion-related acute lung injury and severe anaphylactic episodes.

Neutralizing antibodies to therapeutic enzymes: considerations for testing, prevention and treatment

Lysosomal storage diseases are characterized by deficiencies in lysosomal enzymes, allowing accumulation of target substrate in cells and eventually causing cell death. Enzyme replacement therapy is the principal treatment for most of these diseases. However, these therapies are often complicated by immune responses to the enzymes, blocking efficacy and causing severe adverse outcomes by neutralizing product activity. It is thus crucial to understand the relationships between genetic mutations, endogenous residual enzyme proteins (cross-reactive immunologic material), development of neutralizing antibodies and their impact on clinical outcomes of lysosomal storage diseases. For patients in whom neutralizing antibodies may cause severe adverse clinical outcomes, it is paramount to develop tolerance inducing protocols to preclude, where predictable, or treat such life-threatening responses.

Haptoglobin, inflammation and disease

Haptoglobin is an acute phase protein that scavenges haemoglobin in the event of intravascular or extravascular haemolysis. The protein exists in humans as three main phenotypes, Hp1-1, Hp2-2 and Hp2-1. Accumulated data on the protein's function has established its strong association with diseases that have inflammatory causes. These include parasitic (malaria), infectious (HIV, tuberculosis) and non-infectious diseases (diabetes, cardiovascular disease and obesity) among others. Phenotype-dependent poor disease outcomes have been linked with the Hp2-2 phenotype. The present review brings this association into perspective by looking at the functions of the protein and how defects in these functions associated with the Hp2 allele affect disease outcome. A model is provided to explain the mechanism, which appears to be largely immunomodulatory.

Comparison of acute non-haemolytic transfusion reactions in female and male patients receiving female or male blood components

To study the relationship between antibodies detected in patients’ and/or donors’ sera and the clinical features of acute non-haemolytic transfusion reactions (ANHTRs), and to determine any gender-related difference. ANHTRs range from urticaria to transfusion-related acute lung injury (TRALI). Antibodies to human leukocyte antigen (HLA), granulocytes, platelets, and/or plasma proteins are implicated in some of the ANHTRs. A higher antibody positivity is expected for females than for males. A comparative study of ANHTRs for antibody positivity and their clinical features between females and males for both patients and donors is helpful for characterizing ANHTRs including TRALI more clearly, but such studies are few and outdated. Two hundred and twenty-three ANHTR cases reported by 45 hospitals between October 2000 and July 2005 were analysed. The patients and 196 donors of suspect blood products were screened for antibodies to HLA Class I, HLA Class II, granulocytes, and platelets. The patients were also screened for anti-plasma protein antibodies. The types and severity of ANHTR did not differ significantly between female and male patients. The frequency of the anti-HLA antibodies, but not that of the non-HLA antibodies, was significantly higher in females. Non-HLA antibodies were significantly associated with severe reactions in females. All the TRALI cases had predisposing risk factors for acute lung injury, and 60% of the cases showed anti-leucocyte antibodies. Although the anti-HLA antibodies were detected more frequently in females than males, no significant association of ANHTRs including TRALI with gender, not only for patients, but also for donors, could be shown in this study.

Detection of Hpdel among Thais, a deleted allele of the haptoglobin gene that causes congenital haptoglobin deficiency

BACKGROUND

Congenital haptoglobin deficiency is a risk factor for anaphylactic nonhemolytic transfusion reactions in Japan. The deleted allele of the haptoglobin gene, Hp(del), which causes congenital haptoglobin deficiency, has also been observed in other Northeast Asian populations, such as Korean and Chinese persons. It has not been reported in several African and European-African populations, however, or investigated in other countries.

STUDY DESIGN AND METHODS

To investigate the distribution of congenital haptoglobin deficiency in Southeast Asian countries, blood samples collected from 200 randomly selected healthy Thai volunteers were analyzed for serum haptoglobin and the haptoglobin gene. Plasma haptoglobin concentration was measured to identify haptoglobin deficiency. Haptoglobin phenotyping was performed with sodium dodecyl sulfate-polyacrylamide gel electrophoresis followed by Western blotting. The presence of the Hp(del) allele was determined with genomic DNA by an Hp(del)-specific polymerase chain reaction (PCR) method.

RESULTS

There were no haptoglobin-deficient subjects detected among the 200 Thais. Their haptoglobin phenotypes were as follows: Hp 1-1 in 10, Hp 2-1 in 81, and Hp 2-2 in 109. Six individuals heterozygous for Hp(del) were detected. The frequency of the Hp(del) allele was calculated to be 0.015. The prevalence of haptoglobin deficiency caused by Hp(del) homozygosity was estimated to be approximately 1 in 4000.

CONCLUSION

Congenital haptoglobin deficiency caused by Hp(del) homozygosity is presumed to be present in Thailand as a risk factor for anaphylactic transfusion reactions with a frequency similar to that in Japan. The causative deleted allele of the haptoglobin gene, Hp(del), is distributed among Southeast Asian populations as well as among Northeast Asian populations.

A new strategy for the prevention of IgA anaphylactic transfusion reactions

BACKGROUND

Management of patients with clinically significant anti-IgA is difficult and unsatisfactory in many aspects.

PATIENTS AND METHOD

A 40-year-old man with common variable immunodeficiency had a previous history of anaphylaxis after an intramuscular immunoglobulin administration. His serum contained anti-IgA, and he required immunoglobulins for recurrent infections.

RESULTS

The administration of intravenous immunoglobulins (IVIgG) containing less than 0.1 mg per mL IgA led to an anaphylactic reaction after the transfusion of only 2 to 3 mL. The same IVIgG charge was subsequently pretreated with freshly separated autologous plasma and given to the patient on three consecutive days without any reaction (1.25, 10, and 10 g each in 400 mL plasma). Anti-IgA activity did not increase, and the patient was treated again without complications.

DISCUSSION

Ex vivo pretreatment of IVIgG preparations with autologous plasma appears to be safe and useful in the management of patients with clinically significant anti-IgA. To achieve a significant IgA blockage, the preparation to be used should not contain large amounts of IgA.

CONCLUSION

The strategy described here appears to be safe and may help prevent anaphylaxis in many instances.

Anaphylactic transfusion reactions

PURPOSE OF REVIEW

Although anaphylactic reactions to blood products are rare, the incidence of allergic reactions to blood products is similar to the allergic reaction incidence to penicillin antibiotics, and therefore worthy of proportionate attention. Comprehensive reviews and guidelines of the management of anaphylaxis currently do not include much information on blood products. Current guidelines for the specific management of anaphylactic transfusion reactions are contradictory as to the utility of anti-IgA testing and incomplete by not offering suggestions for the management of non-IgA related reactions.

RECENT FINDINGS

Anti-IgA is not responsible for most reactions. Anti-haptoglobin antibodies are responsible for more reactions than anti-IgA in Japan, but the cause of most reactions is still not known. The incidence of reactions to platelets is the highest compared with fresh frozen plasma and red blood cells. Pre-storage white blood cell reduction of platelets does not decrease the incidence of reactions, indicating that white blood cell-derived cytokines are not responsible for most reactions.

SUMMARY

The increased incidence of reactions to platelets compared with fresh frozen plasma suggests that a platelet-related factor may be responsible for many of the reactions. The possible role of platelet microparticles or activated platelet membranes, which carry a negative charge similar to ionic radiocontrast media, the major cause of iatrogenic anaphylactic reactions in the hospital, is explored.

Risks associated with transfusion of cellular blood components in Canada

We provide a comprehensive review of risks associated with allogeneic red blood cell and platelet transfusions in Canada. The review focuses on clinically symptomatic noninfectious transfusion risks (acute and delayed hemolytic, febrile nonhemolytic [FNHTR], allergic, volume overload, transfusion-related acute lung injury, graft-versus-host disease, and posttransfusion purpura) and the risk of clinically significant disease from transfusion-transmitted infections. Data sources include information from Canadian Blood Services, Héma-Québec, Health Canada, and the Québec Hemovigilance System as well as published information from research studies and international hemovigilance systems. We estimate that in 2000 the aggregate risk of potentially severe reactions (excluding FNHTR and minor allergic reactions) was 43.2 per 100000 red cell units (95% confidence interval [CI]: 38.7-48.1), affecting 337 recipients, and 125.7 per 100000 platelet pools of 5 units (95% CI: 100.8-154.9), affecting 88 recipients. The most frequent potentially severe outcomes for red cell transfusion were hemolytic reactions and volume overload and for platelet transfusion were major allergic reactions and bacterial contamination. The current risk of human immunodeficiency virus and hepatitis C virus transmission is approximately 1 in 4 million and 1 in 3 million units, respectively. These estimates are useful for decisions concerning transfusion therapy, the informed consent process, and for evaluating efficacy of interventions to reduce risk.