Transfusion-related acute lung injury associated with interdonor incompatibility for the neutrophil-specific antigen HNA-1a

The Role of Complement in Transfusion-Related Acute Lung Injury

Transfusion-related acute lung injury (TRALI) is a life-threatening complication of acute respiratory distress occurring within 6 hours of blood transfusion. TRALI is one of the leading causes of transfusion-related fatalities and specific therapies are unavailable. Neutrophils are recognized as the major pathogenic cells, whereas T regulatory cells and dendritic cells appear to be important for protection against TRALI. The pathogenesis, however, is complex and incompletely understood. It is frequently postulated that the complement system plays an important role in the TRALI pathogenesis. In this article, we assess the evidence regarding the involvement of complement in TRALI from both human and animal studies. We hypothesize about the potential connection between the complement system and neutrophils in TRALI. Additionally, we draw parallels between TRALI and other acute pulmonary disorders of acute lung injury and acute respiratory distress syndrome regarding the involvement of complement. We conclude that, even though a role for complement in the TRALI pathogenesis seems plausible, studies investigating the role of complement in TRALI are remarkably limited in number and also present conflicting findings. Different types of TRALI animal models, diverse experimental conditions, and the composition of the gastrointestinal microbiota may perhaps all be factors which contribute to these discrepancies. More systematic studies are warranted to shed light on the contribution of the complement cascade in TRALI. The underlying clinical condition of the patient, which influences the susceptibility to TRALI, as well as the transfusion factor (antibody-mediated vs non–antibody-mediated), will be important to take into consideration when researching the contribution of complement. This should significantly increase our understanding of the role of complement in TRALI and may potentially result in promising new treatment strategies.

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Studies investigating complement and TRALI are limited in number and present conflicting findings.

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Systematic investigation is needed to better understand the contribution of the complement cascade in TRALI.

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Future studies in this area should consider both the clinical susceptibility of the patient as well as the effect of transfusion factors.

Risk factors, management and prevention of transfusion-related acute lung injury: a comprehensive update

Introduction: Despite mitigation strategies that include the exclusion of females from plasma donation or the exclusion of females with a history of pregnancy or known anti-leukocyte antibody, transfusion-related acute lung injury (TRALI) remains a leading cause of transfusion-related morbidity and mortality. Areas covered: The definition of TRALI is discussed and re-aligned with the new Berlin Diagnostic Criteria for the acute respiratory distress syndrome (ARDS). The risk factors associated with TRALI are summarized as are the mitigation strategies to further reduce TRALI. The emerging basic research studies that may translate to clinical therapeutics for the prevention or treatment of TRALI are discussed. Expert opinion: At risk patients, including the genetic factors that may predispose patients to TRALI are summarized and discussed. The re-definition of TRALI employing the Berlin Criteria for ARDS will allow for increased recognition and improved research into pathophysiology and mitigation to reduce this fatal complication of hemotherapy.

Human neutrophil antigen profiles in Banjar, Bugis, Champa, Jawa and Kelantan Malays in Peninsular Malaysia

BACKGROUND

Human neutrophil antigens (HNA) are polymorphic and immunogenic proteins involved in the pathogenesis of neonatal alloimmune neutropenia, transfusion-related acute lung injury (TRALI) and transfusion-related alloimmune neutropenia. The characterisation of HNA at a population level is important for predicting the risk of alloimmunisation associated with blood transfusion and gestation and for anthropological studies.

MATERIALS AND METHODS

Blood samples from 192 healthy, unrelated Malays were collected and genotyped using polymerase chain reaction-sequence specific primers (HNA-1, -3, -4) and polymerase chain reaction-restriction fragment length polymorphisms (HNA-5). The group comprised 30 Banjar, 37 Bugis, 51 Champa, 39 Jawa and 35 Kelantan Malays.

RESULTS

The most common HNA alleles in the Malays studied were HNA-1a (0.641-0.765), -3a (0.676-0.867), -4a (0.943-1.000) and -5a (0.529-0.910). According to principal coordinate plots constructed using HNA allele frequencies, the Malay sub-ethnic groups are closely related and grouped together with other Asian populations. The risks of TRALI or neonatal neutropenia were not increased for subjects with HNA-1, -3 and -4 loci even for donor and recipient or pairs from different Malay sub-ethnic groups. Nonetheless, our estimates showed significantly higher risks of HNA alloimmunisation during pregnancy and transfusion between Malays and other genetically differentiated populations such as Africans and Europeans.

DISCUSSION

This study reports HNA allele and genotype frequencies for the five Malay sub-ethnic groups living in Peninsular Malaysia for the first time. These Malay sub-ethnic groups show closer genetic relationships with other Asian populations than with Europeans and Africans. The distributions of HNA alleles in other lineages of people living in Malaysia (e.g. Chinese, Indian and Orang Asli) would be an interesting subject for future study.

Transfusion-related acute lung injury and leucocyte-reacting antibodies

BACKGROUND AND OBJECTIVES

Transfusion-related acute lung injury (TRALI) is underdiagnosed and underreported. This is why we present cases suspected for TRALI, in which leucocyte antibodies were examined.

MATERIAL AND METHODS

We analysed 44 patients with respiratory insufficiency, related to transfusion, who met criteria of acute lung injury (ALI). Lymphocyte and granulocyte antibodies were examined in donors and patients by six methods.

RESULTS

Based on recent trends, we divided patients into two groups: TRALI (without risk factors for ALI) and possible TRALI (with probable risk factors). The incidence of antibodies was 68.2%, the majority were human leucocyte antigen (HLA) class I and/or II, the minority were non-specific granulocyte antibodies; half of all detected antibodies, however, reacted with granulocytes. Antibodies were found in 17 donors (more often in TRALI than in possible TRALI) and in 19 patients (in four - suspected to be of the donor origin, which would diminish the number of antibodies to 15). In seven available cases, we observed cognate antigen and/or positive cross-match. In the majority of patients, TRALI occurred after transfusion of red cells, in 56.2%- stored above 14 days; all the units were non-leucoreduced. Lookback in two donors showed that transfusions in 20 patients did not result in reported TRALI, even in the patient with cognate antigen.

CONCLUSIONS

Our clinical observations suggest that to distinguish between TRALI and possible TRALI is difficult and the results are equivocal - it is worth considering whether it can be omitted. We have confirmed that antibodies are involved in TRALI, although their role is very complex. The role of stored red blood cells in the development of TRALI requires further observations in comparison with a control group of patients without TRALI.

Report on the Fourth International Granulocyte Immunology Workshop: progress toward quality assessment

BACKGROUND

A formal quality assurance (QA) scheme has been established to facilitate proficiency testing for granulocyte antibodies and antigens.

STUDY DESIGN AND METHODS

Fifteen laboratories participated in the Fourth International Granulocyte Immunology Workshop. The main objective of the workshop was to establish a formal QA scheme for granulocyte serology and molecular typing methods. A secondary objective was to determine the relative sensitivities of the granulocyte immunofluorescence test, granulocyte agglutination test, and MoAb immobilization assays using defined antisera and protocols.

RESULTS

Laboratories scored between 16.7 and 100 percent (mean, 57.5%) of the maximum available in the serologic part of this QA exercise. There were particular problems in detecting granulocyte-specific human neutrophil antigen-1 (HNA-1a) IgM antibodies and HNA-2a antibodies in the presence of HNA-1b antibodies. The granulocyte immunofluorescence test was more sensitive than the granulocyte agglutination test in titration studies, but the latter method more readily identified the presence of HNA-3a antibodies. HNA genotyping was generally well performed, with nine laboratories obtaining 100-percent correct results for HNA-1a, HNA-1b, and HNA-1c.

CONCLUSIONS

There is a need to standardize the detection of granulocyte-specific antibodies. Laboratories with good performance tended to use two methods for detecting granulocyte-specific antibodies and an HNA-typed panel of granulocytes. The use of a method for elucidating mixtures of granulocyte- and lymphocyte-reactive antibodies (e.g., MoAb immobilization assay) and the use of methods for detecting both cytotoxic and noncytotoxic HLA class I antibodies were also associated with a higher than average performance.

Recurrent transfusion-related acute lung injury

BACKGROUND

Transfusion-related acute lung injury (TRALI) is a rare condition that is commonly associated with the transfusion of donor plasma containing WBC antibodies. Biologically active lipids that accumulate during storage of RBCs and platelets may also cause TRALI. There has been only one previously reported case of recurrent TRALI.

CASE REPORT

A patient received a transfusion 2 days after undergoing hysterectomy; she developed TRALI after receiving the transfusion. The patient recovered after being on ventilation for 6 days but received an additional transfusion and had a second episode of TRALI, which required further ventilation.

RESULTS

Laboratory investigation of the first episode of TRALI suggested the presence of HLA-A2 (N = 1) and granulocyte-specific IgM antibodies (N = 2) in the sera from three of the donors. All three sera reacted in crossmatch studies with the patient's granulocytes and lymphocytes. Lymphocyte-specific IgG antibodies were detected in the patient's serum. There was no evidence to suggest the involvement of WBC antibodies in the second episode of TRALI. Antibody screening of the donors' samples and both forward and reverse crossmatch studies were negative.

CONCLUSION

The first episode of TRALI seems to be due to the action of HLA-A2 and granulocyte-specific IgM antibodies. The second episode may have been due to the action of lipid neutrophil-priming agents in the donors' units in association with the patient's underlying pulmonary condition (i.e., recovering from lung injury). TRALI can recur if a patient requires further transfusion support shortly after an initial episode of TRALI.