Determination of neutrophil antigen HNA-3a and HNA-3b genotype frequencies in six racial groups by high-throughput 5' exonuclease assay

Anti-HNA testing of allo-exposed COVID-19 convalescent plasma donors including genetic human neutrophil antigen screening to prevent anti-HNA antibody-mediated transfusion-related acute lung injury

BACKGROUND

Transfusion-related acute lung injury caused by antibodies against human neutrophil antigens (HNA) is a serious but rare complication associated with blood transfusion. The presence of such antibodies is most probable in donors with a transfusion/pregnancy history. During the COVID-19 pandemic period convalescent plasma (CP) containing neutralizing antibodies against SARS-CoV-2 was widely used for COVID-19 patients as a therapy in the absence of any treatment. The aim of the study was to work out a simple diagnostic algorithm of anti-HNA testing of allo-exposed CP donors including genetic HNA screening.

MATERIALS AND METHODS

A total of 457 anti-HLA-negative allo-exposed CP donors were genotyped for HNA-1a/1b, HNA-3a/3b, and HNA-2, and only donors with homozygous HNA-1a/1a; HNA-3b/3b; or HNA-2null genotypes were tested for anti-HNA antibody using LabScreenMulti (One Lambda) and homozygous HNA-1b/1b using the granulocyte immunofluorescence test (GIFT) but verified using LabScreenMulti.

RESULTS

Testing of 83 homozygous HNA-3b/3b; HNA-2null; or HNA-1a/1a donors revealed anti-HNA-3a antibody in one case. Testing of 181 HNA-1b/1b donors using GIFT gave 10 ambiguous results verified using LabScreenMulti which confirmed anti-HNA-1a antibody in one case. The frequency of FCGR3B*01 and *04 encoding HNA-1a was 0.34; FCGR3B*02, *03, and *05 encoding HNA-1b-0.66; SLC44A2*01 encoding HNA-3a-0.80; and SLC44A2*02 encoding HNA-3b-0.20. In 3.7% cases the HNA-2null genotype was revealed.

DISCUSSION

Due to applying HNA genotyping as a primary test before anti-HNA antibody testing the serological work was limited only to HNA-homozygous donors revealing two anti-HNA immunized donors. The distribution of HNA genotypes in the cohort was similar to other Caucasian populations.

Kidney transplant outcomes in patients with antibodies to human neutrophil antigen 3a

BACKGROUND

Antibody mediated rejection (ABMR) of kidney transplants has been shown to occur in the absence of a known donor specific antibody to human leucocyte antigen (HLA). Antibodies to the human neutrophil antigen (HNA) system have been detected in kidney transplant recipients and linked to ABMR in the absence of an HLA donor specific antibody (DSA), but there remains limited literature regarding this.

METHODS

Case series analysis was carried out examining three cases of HNA-3a antibody positive flow cytometry cross match (FC-XM) from two transplant centres in Scotland.

RESULTS

All patients included were female and had been sensitised as a result of pregnancy. One live donor recipient with HNA-3a antibodies identified prior to transplant received ATG induction and has had a good outcome. The remaining two patients received deceased donor transplants. HNA-3a antibodies were indicated following a retrospective flow cytometry crossmatch. Both patients received Basiliximab induction and both have experienced ABMR requiring supplementary immunosuppression.

CONCLUSIONS

The predicted rate of HNA-3a antibodies amongst patients awaiting kidney transplant in the UK is <1%. However, with increasing evidence to support a role for HNA-3a antibodies in the development of ABMR there may be value in screening at risk groups to allow for augmented immunosuppression to be considered at the time of kidney transplant.

World human neutrophil antigens investigation survey

BACKGROUND AND OBJECTIVES

Human neutrophil antigens (HNAs) are categorized into five systems: HNA-1 to HNA-5. Given the importance of neutrophils in immunity, we sought to create awareness of the role of HNA diagnostic services in managing immune neutropenia and transfusion-related acute lung injury. To provide health communities all around the world with access to these services, we conducted a survey to create a directory of these HNA diagnostic services.

MATERIALS AND METHODS

An Excel table-based survey was created to capture information on the laboratory's location and was emailed to 55 individuals with known or possible HNA investigation activity. The collected data were then summarized and analysed.

RESULTS

Of contacted laboratories, the surveys were returned from 23 (38.2%) laboratories; 17 have already established HNA diagnostic (of them 12 were regular participants of the International Granulocyte Immunobiology Workshop [ISBT-IGIW]), 4 laboratories were in the process of establishing their HNA investigation and the remaining 2 responder laboratories, did not conduct HNA investigations. In established laboratories, investigation for autoimmune neutropenia (infancies and adults) was the most frequently requested, and antibodies against HNA-1a and HNA-1b were the most commonly detected.

CONCLUSION

The directory of survey respondents provides a resource for health professionals wanting to access HNA diagnostic services. The present study offers a comprehensive picture of HNA diagnostics (typing and serology), identifying weak points and areas for improvement for the first time. Identifying more laboratories involved in HNA diagnostics with limited access to international societies in the field will globally improve HNA diagnostics.

Impaired adhesion of neutrophils expressing Slc44a2/HNA-3b to VWF protects against NETosis under venous shear rates

Genome-wide association studies linked expression of the human neutrophil antigen 3b (HNA-3b) epitope on the Slc44a2 protein with a 30% decreased risk of venous thrombosis (VT) in humans. Slc44a2 is a ubiquitous transmembrane protein identified as a receptor for von Willebrand factor (VWF). To explain the link between Slc44a2 and VT, we wanted to determine how Slc44a2 expressing either HNA-3a or HNA-3b on neutrophils could modulate their adhesion and activation on VWF under flow. Transfected HEK293T cells or neutrophils homozygous for the HNA-3a- or HNA-3b-coding allele were purified from healthy donors and perfused in flow chambers coated with VWF at venous shear rates (100 s-1). HNA-3a expression was required for Slc44a2-mediated neutrophil adhesion to VWF at 100 s-1. This adhesion could occur independently of β2 integrin and was enhanced when neutrophils were preactivated with lipopolysaccharide. Moreover, specific shear conditions with high neutrophil concentration could act as a "second hit," inducing the formation of neutrophil extracellular traps. Neutrophil mobilization was also measured by intravital microscopy in venules from SLC44A2-knockout and wild-type mice after histamine-induced endothelial degranulation. Mice lacking Slc44a2 showed a massive reduction in neutrophil recruitment in inflamed mesenteric venules. Our results show that Slc44a2/HNA-3a is important for the adhesion and activation of neutrophils in veins under inflammation and when submitted to specific shears. The fact that neutrophils expressing Slc44a2/HNA-3b have a different response on VWF in the conditions tested could thus explain the association between HNA-3b and a reduced risk for VT in humans.

Implication of antibodies against human leukocyte antigen in simultaneous presentation of fetal and neonatal alloimmune thrombocytopenia and neutropenia

Fetal and neonatal alloimmune thrombocytopenia (FNAIT) and neonatal alloimmune neutropenia (NAN) are two rare complications of newborns caused by antibodies against paternal inherited antigens. Human platelet (HPA) and neutrophil antigens (HNA) are the common targets. Human leukocyte antigen (HLA) class I proteins are also expressed on platelets and neutrophils and anti-HLA antibodies have occasionally been implicated in these complications. We report a premature twin infant who presented with severe thrombocytopenia and neutropenia clinically compatible with FNAIT and NAN, from a mother with no identifiable HPA or HNA antibodies, but with very high levels of complement-fixing antibodies against paternal inherited HLA. These antibodies were also detected in the infant. HLA antibodies are commonly present in multiparous women who deliver healthy infants. They can, however, be cytotoxic and cause clinical complications after blood products transfusion (TRALI and becoming refractory to platelets transfusion) and after organ transplantation (allogeneic organ rejection).

HNA-3a and HNA-3b antigens among 9 ethnic populations and the Han population in Southwest China

Background

Human neutrophil antigen 3 (HNA-3) is encoded by the SLC44A2 gene. Antibodies against HNAs can cause severe, often fatal, transfusion reactions, known as transfusion-related acute lung injury, and neonatal neutropenia. We explored the 2 common HNA-3 variants in 9 ethnic populations residing in Sichuan and Yunnan provinces of China as compared to the Han population.

Methods

We genotyped for SLC44A2 (rs2288904) by polymerase chain reaction sequence-based typing among blood donors, for a total of 2206 individuals in Yunnan and 376 in Sichuan.

Results

The SLC44A2*02 allele (HNA-3b antigen) frequency varied between 0.24 and 0.33 for all 9 ethnic populations in Yunnan, including Zhuang, Derung, Hani, Lisu, Bai, Miao, Dai, Naxi, and Yi. Specifically, the Yi ethnicity did not present an unusually great SLC44A2*02 frequency at any of the 4 locations examined in Yunnan. Except of the Yi ethnicity in Sichuan (0.40), the Han ethnicity, as the majority population group, had the greatest SLC44A2*02 frequency with 0.39 in Yunnan and 0.35 in Sichuan.

Conclusion

The ethnic populations in Southwest China are not at an increased risk for anti-HNA3a compared to the Han population, with the possible exception of Yi in Sichuan. Our data, however, corroborated the known high prevalence of SLC44A2*02 in Han populations. Hence, the Han populations in Yunnan, Sichuan and elsewhere in China are at a comparatively great risk for developing HNA-3a antibodies.

A study of human neutrophil antigen genotype frequencies in Hong Kong

BACKGROUND

Alloantibodies against human neutrophil antigens (HNA) are associated with a variety of clinical conditions. Over the past decade, the allelic and genotypic frequencies of the five HNA systems have been evaluated. Although the HNA system is less polymorphic than human leukocyte antigens (HLA), significant differences in the genotypic and allele frequencies still exist in different populations, even those living in close proximity.

OBJECTIVES

To delineate HNA genotypic and allele frequencies to provide vital information on estimating the risk of HNA-associated diseases for our local population.

METHODS

Using a validated, in-house-developed assay, genotyping for HNA-1, HNA-3, HLA-4 and HNA-5 was performed on 300 samples from Chinese blood donors from Hong Kong. In addition, the frequency of the HNA-2 c.843A > T allele was also determined.

RESULTS

The allele frequencies of HNA-1a, -1b and -1c alleles were 67·8, 31·5 and 0%, respectively, whereas the frequencies of HNA-3a and HNA-3b were 71·0 and 29·0%, respectively. The frequencies of HNA-4a and -4b alleles were 99·5 and 0·5%, respectively, and for HNA-5a and -5b, alleles were 85·2 and 14·8%, respectively. Homozygotes for the HNA-2 c.843 TT variant were absent in our population, whereas only <4% of the population were c.843AT heterozygote carriers.

CONCLUSIONS

This is the first study to define HNA genotype and allele frequencies using a validated modified in-house PCR-SSP method in the Hong Kong Chinese blood donor population. Our approach provides a cost-effective assay for conducting routine HNA typing and facilitates the incorporation of these assays into routine clinical service. Our results are comparable with those reported in the Guangzhou Chinese population, but the allele frequencies in our Hong Kong Chinese population are significantly different from the reported European frequencies, confirming that a geographical difference exists for HNA allele frequencies.

Genotype frequencies of human neutrophil antigen-3 in the Chinese Zhuang and Dong populations

Individuals with the human neutrophil antigen (HNA)-3b/3b type can produce HNA-3a antibodies, which have been reported to cause severe, sometimes fatal transfusion-related acute lung injury (TRALI). Our study aimed to determine the genotype frequency of HNA-3a/3b which will be helpful to estimate the potential risk for forming anti-HNA-3a, the clinically relevant antibody linked to TRALI in two different ethnic groups of southern China. Five hundred unrelated and healthy blood donors (284 male, 216 female; 300 Zhuangs, 200 Dongs) from the Guangxi Zhuang Autonomous Region were simultaneously typed for the HNA-3 allele using a polymerase chain reaction sequence-based typing (PCR-SBT) method. Genotype frequencies of HNA-3a/3a, HNA-3a/3b and HNA-3b/3b were 51.7%, 39.7% and 8.6% in the Zhuang population, and 44.0%, 49.0% and 7.0% in the Dong population, respectively. Homozygous HNA-3b/3b genotype frequency among the Zhuang population (8.6%) was significantly higher than previously reported in African Americans (0.4%), Brazilians (3.6%) and English Caucasians (2.9%) (p < .05). And the HNA-3b/3b genotype frequency among the Dong population was higher than African Americans (0.4%) (p < .05). This study showed Chinese Zhuang and Dong populations possessed a higher frequency of HNA-3b/3b genotype, suggesting that they may be at greater risk for developing anti-HNA-3a alloantibodies that may cause severe cases of TRALI. A molecular-based identification of the HNA-3b/3b genotype in all multiparous female blood donors was suggested to reduce the risk of TRALI following plasma and whole blood allogeneic transfusions.

Genotype frequency of human neutrophil antigen-3 polymorphisms in the Yi, Han, and Tibetan populations of China

BACKGROUND

Human neutrophil antigen-3 (HNA-3) alloantibodies can cause fatal transfusion-related acute lung injury (TRALI). Most frequencies of SLC44A2 alleles encoding the HNA-3a/b antigens have been established in Han individuals by polymerase chain reaction with sequence-specific priming (PCR-SSP). We sequenced SLC44A2 gene fragments and determined allele frequencies in three ethnicities of China.

STUDY DESIGN AND METHODS

Genomic DNA was extracted from 448 samples of 100 blood donors of Yi ethnicity in Xichang, Liangshan; 248 Han in Nanjing, Jiangsu; and 100 Tibetan in Lhasa, Tibet. A PCR-SSP was applied to determine the phase of two single-nucleotide polymorphisms (SNPs); SLC44A2 haplotypes were constructed.

RESULTS

In the 567 nucleotides of the SLC44A2 gene covered by our sequencing approach in Han individuals, we detected the known 331-44G>A (rs12972963) and 461G>A (rs2288904) polymorphisms. In the 243 nucleotides sequenced in Yi and Tibetan populations, we detected the known 461G>A and 503-15T>C (rs1560711) polymorphisms. A PCR-SSP for the common HNA-3a/b SNP was 100% concordant. The frequencies of the HNA-3a allele were 0.58, 0.66, and 0.69 in Yi, Han (Nanjing), and Tibetan, respectively (0.42, 0.34, and 0.31 for HNA-3b).

CONCLUSIONS

The Yi population of China had the highest frequency of blood donors at risk of harboring anti-HNA-3a compared to any population studied so far. We confirmed that the underlying SLC44A2*2 allele is more common in China than in any European or African populations.

Full-length nucleotide sequences of 30 common SLC44A2 alleles encoding human neutrophil antigen-3

BACKGROUND

Human neutrophil antigen-3a (HNA-3a) alloantibodies can cause severe transfusion-related acute lung injury. The frequencies of the single-nucleotide polymorphisms (SNPs) indicative of the two clinically relevant HNA-3a/b antigens are known in many populations. In this study, we determined the full-length nucleotide sequence of common SLC44A2 alleles encoding the choline transporter-like protein-2 that harbors HNA-3a/b antigens.

STUDY DESIGN AND METHODS

A method was devised to determine the full-length coding sequence (CDS) and adjacent intron sequences from genomic DNA by eight polymerase chain reaction amplifications covering all 22 SLC44A2 exons. Samples from 200 African American, 96 Caucasian, two Hispanic, and four Asian blood donors were analyzed. We developed a decision tree to determine alleles (confirmed haplotypes) from the genotype data.

RESULTS

A total of 10 SNPs were detected in the SLC44A2 CDS. The noncoding sequences harbored an additional 28 SNPs (one in the 5'-untranslated region [UTR]; 23 in the introns; and four in the 3'-UTR). No SNP indicative of a nonfunctional allele was detected. The nucleotide sequences for 30 SLC44A2 alleles (haplotypes) were confirmed. There may be 66 haplotypes among the 604 chromosomes screened.

CONCLUSIONS

We found 38 SNPs, including one novel SNP, in 8192 nucleotides covering the CDS of the SLC44A2 gene among 302 blood donors. Population frequencies of these SNPs were established for African Americans and Caucasians. Because alleles encoding HNA-3b are more common than non-functional SLC44A2 alleles, we confirmed our previous postulate that African American donors are less likely to form HNA-3a antibodies compared to Caucasians.

Spotlight on pathogenesis of TRALI: HNA-3a (CTL2) antibodies

Human neutrophil antigen-3a (HNA-3a) antibodies contained in donor plasma can result in severe, sometimes fatal transfusion-related acute lung injury (TRALI). Recent developments in TRALI secondary to antibodies to HNA-3a antigen span diagnosis, pathophysiology, treatment, and prevention resulting in improved understanding, potential treatments, and mitigation strategies. First, on the molecular level, characterization of HNA-3 antigen has allowed for genotyping methods that clarify population prevalence. Related work has led to generation of multiple antibody detection assays. These assays aid in determining potential populations at risk and potential mitigation strategies. Second, the development of TRALI requires a hit from the patient and from the product. Anti-HNA-3a is one of the product-derived factors and appears to result in TRALI by binding directly to pulmonary endothelium as well as to neutrophils expressing the corresponding antigen. Finally, potential mitigation strategies include red blood cell product filtration to remove anti-HNA-3a as well as other antibodies.

HNA-3 gene frequencies in Brazilians and a new polymerase chain reaction-restriction fragment length polymorphism method for HNA-3a/3b genotyping

BACKGROUND

HNA-3 antigens are the result of a rs2288904 single-nucleotide polymorphism (SNP) in the CTL2, and the HNA-3a and HNA-3b variants are encoded by a guanine and adenine at Nucleotide Position 461. Anti-HNA-3 are involved in severe transfusion-related acute lung injury reactions and in neonatal alloimmune neutropenia. Since the distribution of the HNA-3 system was unknown in South Americans, in this study we determined the frequency of the HNA-3 alleles in Brazilians.

STUDY DESIGN AND METHODS

DNA of 500 blood donors, 120 Xikrin Amerindians, 74 Japanese individuals, and 124 African Brazilians were genotyped for rs2288904 by a polymerase chain reaction (PCR)-restriction fragment length polymorphism assay. The PCR product was digested with enzyme Taq(α) 1, specific to nucleotide guanine (HNA-3a).

RESULTS

The results showed that the frequencies of the HNA-3a/HNA-3b alleles were 0.81/0.19 in blood donors, 1.00/0.00 in Amerindians, 0.63/0.37 in Japanese, and 0.85/0.15 in African Brazilians. All 81 individuals genotyped as HNA-3a/a did not present the SNP c.457T by molecular sequencing.

CONCLUSION

The frequencies of HNA-3 genotypes in Brazilian blood donors is similar to that described in Caucasians; however, all Amerindians were HNA-3a/a, African Brazilians showed a lower frequency of HNA-3b/b, and Japanese had a higher prevalence of HNA-3b/b, suggesting that they may be at risk for developing anti-HNA-3a alloantibodies.

Human neutrophil alloantigen genotype frequencies in Thai blood donors

BACKGROUND

Antibodies to human neutrophil antigens (HNA) can cause transfusion reactions, as well as autoimmune and neonatal neutropenia. This study is the first to report the frequencies of human neutrophil antigen genotypes in the Thai population.

MATERIALS AND METHODS

Three hundred unrelated, healthy Thai blood donors at the National Blood Centre, Thai Red Cross Society, Bangkok, Thailand were typed for HNA-1a, -1b, -1c, -3a, -3b and -4a using polymerase chain reaction with sequence-specific primers. Moreover, HNA-5a genotyping was performed using polymerase chain reaction-restriction fragment length polymorphism.

RESULTS

The gene frequencies of HNA-1a, -1b and -1c were 0.470, 0.530 and 0.005, respectively. The frequencies of HNA-3a and -3b were 0.490 and 0.510, respectively. Additionally, the HNA-4a+/+ and HNA-4a+/- genotype frequencies were 0.947 and 0.053, respectively. The frequencies of HNA-5a+/+, HNA-5a+/- and HNA-5a-/- genotypes were 0.641, 0.297 and 0.062, respectively. Compared with other Asian populations, Thais have higher frequencies of HNA-1b (P<0.001). On the other hand, the frequency of HNA-5a observed in Thais is lower than that reported among Koreans (P<0.001).

DISCUSSION

These findings suggest that Thais would be more susceptible to HNA-1b alloimmunisation. Furthermore, our results could establish a useful human neutrophil antigen donor file to provide more effective transfusion of blood and blood components.