Platelet glycoprotein IIb/IIIa (HPA-1 and HPA-3) polymorphisms in patients with hemorrhagic fever with renal syndrome

Host genetic factors associated with the range limit of a European hantavirus

The natural host ranges of many viruses are restricted to very specific taxa. Little is known about the molecular barriers between species that lead to the establishment of this restriction or generally prevent virus emergence in new hosts. Here, we identify genomic polymorphisms in a natural rodent host associated with a strong genetic barrier to the transmission of European Tula orthohantavirus (TULV). We analysed the very abrupt spatial transition between two major phylogenetic clades in TULV across the comparatively much wider natural hybrid zone between evolutionary lineages of their reservoir host, the common vole (Microtus arvalis). Genomic scans of 79,225 single nucleotide polymorphisms (SNPs) in 323 TULV‐infected host individuals detected 30 SNPs that were consistently associated with the TULV clades CEN.S or EST.S in two replicate sampling transects. Focusing the analysis on 199 voles with evidence of genomic admixture at the individual level (0.1–0.9) supported statistical significance for all 30 loci. Host genomic variation at these SNPs explained up to 37.6% of clade‐specific TULV infections. Genes in the vicinity of associated SNPs include SAHH, ITCH and two members of the Syngr gene family, which are involved in functions related to immune response or membrane transport. This study demonstrates the relevance of natural hybrid zones as systems not only for studying processes of evolutionary divergence and speciation, but also for the detection of evolving genetic barriers for specialized parasites.

Human platelet antigen 1-6, 9 and 15 in the Iranian population: An anthropological genetic analysis

Human platelet antigens (HPAs) are membranous glycoproteins considered as alloantigens due to their polymorphisms. HPA-incompatibility in multiple pregnancies or blood transfusion can induce the development of alloantibodies leading to thrombocytopenia. The frequency of HPAs varies among populations, so that deep knowledge of HPA frequencies will help us to reduce those incompatibilities. Herein, we studied the allele and genotype frequencies of HPA1-6, HPA9, and HPA15 among the Iranians with intra- and inter-populations analyses on 36 worldwide populations with diverse ethnicities. The analysis shows that the HPA2 and HPA5 have the greatest differences in genotype distribution between the Iranians and other nations, although similar to other populations, the sole allele found in HPA4, 6, and 9 is “a”. Despite other HPAs, the most frequent allele in HPA15 is “b”, which is also abundant in HPA3. Hierarchical clustering indicates the highest degree of global similarity in HPA genotype frequency among Iranian, Argentinian, Brazilian, and German Turkish populations. Our findings can be applied to decrease the risk of alloimmunizations and platelet disorders, especially in neonates.

A Single-Nucleotide Polymorphism of αVβ₃ Integrin Is Associated with the Andes Virus Infection Susceptibility

The AndesOrthohantavirus (ANDV), which causes the hantavirus cardiopulmonary syndrome, enters cells via integrins, and a change from leucine to proline at residue 33 in the PSI domain (L33P), impairs ANDV recognition. We assessed the association between this human polymorphism and ANDV infection. We defined susceptible and protective genotypes as “TT” (coding leucine) and “CC” (coding proline), respectively. TT was present at a rate of 89.2% (66/74) among the first cohort of ANDV cases and at 60% (63/105) among exposed close-household contacts, who remained uninfected (p < 0.05). The protective genotype (CC) was absent in all 85 ANDV cases, in both cohorts, and was present at 11.4% of the exposed close-household contacts who remained uninfected. Logistic regression modeling for risk of infection had an OR of 6.2–12.6 (p < 0.05) in the presence of TT and well-known ANDV risk activities. Moreover, an OR of 7.3 was obtained when the TT condition was analyzed for two groups exposed to the same environmental risk. Host genetic background was found to have an important role in ANDV infection susceptibility, in the studied population.

Human platelet antigens in disease

Platelets have various functions and participate in primary hemostasis, inflammation, and immune responses. Human platelet antigens (HPAs) are alloantigens expressed on the platelet membrane. Each HPA represent one of six platelet glycoproteins GPIIb, GPIIIa, GPIa, GPIbα, GPIbβ, and CD109, and six biallelic systems are grouped. A single nucleotide polymorphism (SNP) in the gene sequence causes a single amino acid substitution of relevant platelet glycoprotein with the exception of HPA-14bw. High-throughput next-generation sequencing-based method has been developed, which enable accurately identification of HPA polymorphisms. The roles of HPA in disease were reviewed. HPAs mediate platelet-microorganism and platelet-malignant cell interactions, and they also participate in pathogenesis of hemorrhagic fever with renal syndrome and infective endocarditis. The exploration of HPA polymorphisms in association with disease susceptibility of individuals will benefit prevention or management of disease.

Human platelet antigens are associated with febrile non-hemolytic transfusion reactions

BACKGROUND

Febrile non-hemolytic transfusion reaction (FNHTR) is the most common type of transfusion reactions, and it could be reduced by transfusing patients with leukocyte-poor blood products. However, FNHTR still occur in certain patients transfused with leukocyte-poor red blood cell (LPR) products. It is examined whether human platelet antigen (HPA) could be a potential membrane antigen that plays a role in FNHTR.

METHODS

A total of 120 inpatient subjects who transfused with LPR (60 in FNHTR group, 60 in control group) were typed for HPA-2, HPA-3, and HPA-15 using sequence specific primer-polymerase chain reaction (SSP-PCR) and electrophoresis.

RESULTS

HPA-2 unmatched rate between donors and patients in FNHTR group was 18%, and only 3% unmatched rate was observed in control group (p=0.0082). FNHTR group was further classified according to the imputability. There was a significant difference (p=0.0041) between FNHTR (probable imputability, infection) group and control group, and more significant difference (p=0.0008) was seen between FNHTR (probable imputability, febrile neutropenia) group and control group.

CONCLUSIONS

Those results indicated that HPA-2 might play roles on inducing FNHTR in patients suffering from infectious diseases and febrile neutropenia. HPA-2 genotyping between donors and recipients might be worth integrating in pre-transfusion testing to increase transfusion safety.

Lack of association between integrin αvβ3 gene polymorphisms and hemorrhagic fever with renal syndrome in Han Chinese from Hubei, China

Hantaviruses belong to the family Bunyaviridae and cause hemorrhagic fever with renal syndrome (HFRS) in humans. β₃ integrins, including α_Vβ₃ and α_IIbβ₃ integrins, act as receptors on endothelial cells and play key roles in cellular entry during the pathogenesis of hantaviruses. Previous study demonstrated that the polymorphisms of integrin α_IIbβ₃ are associated with susceptibility to hantavirus infection and the disease severity of HFRS in Shaanxi Province of China, rather than in Finland. However, the polymorphisms of integrin α_vβ₃ in patients with HFRS was incompletely understood. Here, we aimed to investigate the associations between polymorphisms in human integrin α_vβ₃ and HFRS in Han Chinese individuals. Ninety patients with HFRS and 101 healthy controls were enrolled in this study. Analysis of five single nucleotide polymorphism (SNP) sites (rs3768777 and rs3738919 on ITGAV; rs13306487, rs5921, and rs5918 on ITGB3) was performed by TaqMan SNP genotyping assays and bi-directional PCR allele-specific amplification method. No significant differences were observed between the HFRS group and controls regarding the genotype and allele frequency distributions of any of the five SNP sites, and no associations were found between ITGAV polymorphisms/genotypes and disease severity. In conclusion, our results implied that these five SNPs in the integrin α_vβ₃ gene were not associated with HFRS susceptibility or severity in Han Chinese individuals in Hubei Province.

Immunogenetic factors affecting susceptibility of humans and rodents to hantaviruses and the clinical course of hantaviral disease in humans

We reviewed the associations of immunity-related genes with susceptibility of humans and rodents to hantaviruses, and with severity of hantaviral diseases in humans. Several class I and class II HLA haplotypes were linked with severe or benign hantavirus infections, and these haplotypes varied among localities and hantaviruses. The polymorphism of other immunity-related genes including the C4A gene and a high-producing genotype of TNF gene associated with severe PUUV infection. Additional genes that may contribute to disease or to PUUV infection severity include non-carriage of the interleukin-1 receptor antagonist (IL-1RA) allele 2 and IL-1β (-511) allele 2, polymorphisms of plasminogen activator inhibitor (PAI-1) and platelet GP1a. In addition, immunogenetic studies have been conducted to identify mechanisms that could be linked with the persistence/clearance of hantaviruses in reservoirs. Persistence was associated during experimental infections with an upregulation of anti-inflammatory responses. Using natural rodent population samples, polymorphisms and/or expression levels of several genes have been analyzed. These genes were selected based on the literature of rodent or human/hantavirus interactions (some Mhc class II genes, Tnf promoter, and genes encoding the proteins TLR4, TLR7, Mx2 and β3 integrin). The comparison of genetic differentiation estimated between bank vole populations sampled over Europe, at neutral and candidate genes, has allowed to evidence signatures of selection for Tnf, Mx2 and the Drb Mhc class II genes. Altogether, these results corroborated the hypothesis of an evolution of tolerance strategies in rodents. We finally discuss the importance of these results from the medical and epidemiological perspectives.

Association of platelet ITGA2B and ITGB3 polymorphisms with ex vivo antiplatelet effect of ticagrelor in healthy Chinese male subjects

Ticagrelor (TIC) is the first reversible P2Y12 receptor antagonist that exhibits rapid antiplatelet effect by indirect inhibition of the GPIIb/IIIa complex. Polymorphisms in genes coding GPIIb/IIIa, namely ITGA2B and ITGB3, are associated with aspirin resistance and risk for thrombotic diseases. We assessed whether ITGA2B and ITGB3 polymorphisms can influence the ex vivo antiplatelet activity of ticagrelor in Chinese population. A total of 196 healthy Chinese male individuals were recruited. ADP-induced platelet aggregation was determined using optical aggregometry at baseline and after incubation of the platelet-rich plasma with 15 and 50 μM ticagrelor, respectively. Single nucleotide polymorphisms in ITGA2B (rs5911 G>T) and ITGB3 (rs4642 A>G and rs4634 G>A) were genotyped by sequencing. TIC at both concentrations of 15 and 50 μM decreased ADP-induced platelet aggregation significantly (P < 0.05, respectively). As compared to ITGA2B rs5911 GG homozygotes, individuals with the rs5911 TG genotype showed significantly increased inhibition of platelet aggregation (IPA) by both 15 and 50 μM ticagrelor incubation (P < 0.05, respectively). Neither rs4642 nor rs4634 polymorphism affected ticagrelor-induced IPA. We suggest that the ITGA2B rs5911 GG genotype is associated with decreased ex vivo antiplatelet activity of ticagrelor in healthy Chinese male subjects.

Polymorphisms of PAI-1 and platelet GP Ia may associate with impairment of renal function and thrombocytopenia in Puumala hantavirus infection

INTRODUCTION

Puumala virus (PUUV) infection is a viral hemorrhagic fever with renal syndrome (HFRS) characterized by thrombocytopenia and acute impairment of renal function. We aimed to assess whether genetic polymorphisms of platelet antigens together with those of von Willebrand factor (VWF) and plasminogen activator inhibitor (PAI-1) correlate with disease severity. Patients and methods 172 consecutive hospital-treated patients with serologically confirmed acute PUUV infection were included. Platelet glycoprotein (GP) IIIa T>C (rs5918), GP Ia T>C (rs1126643), GP Ib C>T (rs6065), GP VI T>C (rs1613662), VWF A>G (rs1063856) and PAI-1 A>G (rs2227631) were genotyped. The associations of the rarer alleles with variables reflecting the severity of the disease were analyzed.

RESULTS

PAI-1G-carriers had higher maximum creatinine level compared with the non-carriers (median 213 μmol/l, range 60-1499 μmol/l vs. median 122 μmol/l, range 51-1156 μmol/l, p = 0.01). The GG-genotypes had higher creatinine levels than GA- and AA-genotypes (medians 249 μmol/l, 204 μmol/l and 122 μmol/l, respectively, p = 0.03). Polymorphisms of GP VI and VWF associated with lower creatinine levels during PUUV infection. The minor C-allele of GP Ia associated with lower platelet counts (median 44 × 10(9)/l, range 20-90 × 10(9)/l vs median 64 × 10(9)/l, range 3-238 × 10(9)/l; p = 0.02).

CONCLUSIONS

Polymorphism of PAI-1, a major regulator of fibrinolysis, has an adverse impact on the outcome of kidney function in PUUV-HFRS. Platelet collagen receptor GP Ia polymorphism associates with lower platelet count.

Human platelet antigen allele frequencies and new mutations on platelet glycoprotein genes in the Chinese Han population

BACKGROUND AND OBJECTIVES

The frequencies of human platelet antigens (HPAs) vary between different populations. In this study, we determined the HPA allele frequencies in the Chinese Han population and identified situation of incompatibility possibly leading to alloimmunisation.

METHODS

A total of 750 volunteer blood donors of the Chinese Han population were genotyped for HPA-1 to -17w systems. HPA genotyping was determined by polymerase chain reaction sequence-based typing.

RESULTS

Among the 17 HPA systems, the allele frequency is different from other populations. We noted the absence of HPA-7bw to HPA-14bw, HPA-16bw and HPA-17bw alleles in the population. The estimated incompatibility probabilities regarding platelet antigens 1 to 6w and 15 systems after transfusion of random donor platelet were from 0·004 to 0·373. Thirteen glycoprotein alleles were observed in the population. In addition, we identified 16 novel mutations on the glycoprotein genes separated from HPA polymorphisms, including GP1BA (517-525delAAC), ITGA2B (2722C>T and IVS26+85T>C), ITGA2 (1521C>T, 2474T>G and IVS20+10 G>C), ITGB3 (1476G>A, IVS10+19C>A, 1813G>A, IVS11+21G>A, IVS11+152A>G and IVS11-104T>C), GP1BB (IVS1-79G>A, IVS1-27C>T and 129G>A) and CD109 (2139A>G). Five of them could lead to amino acid deletion, substitution or premature stop codon in corresponding glycoprotein.

CONCLUSIONS

There was a high degree of polymorphism of the membrane glycoprotein genes related to human platelet alloantigen-1 to -17w systems in the Chinese Han population. These data could have some impact on the diagnosis, prevention and treatment of alloimmune thrombocytopenia.

Enhanced thrombin formation and fibrinolysis during acute Puumala hantavirus infection

INTRODUCTION

Nephropathia epidemica (NE) is a viral hemorrhagic fever with renal syndrome associated with thrombocytopenia and mild bleeding. We assessed activation of coagulation and fibrinolysis during the acute phase of NE.

MATERIALS AND METHODS

19 hospital-treated patients were involved. Plasma levels of D-dimer, prothrombin fragments 1+2 (F1+2), activated partial thromboplastin time (APTT), prothrombin time (PT%), thrombin time (TT), fibrinogen, antithrombin (AT), protein S free antigen (PS), protein C (PC) and complete blood count (CBC) were measured three times during the acute phase and once at 32-54 days after the onset of fever (recovery phase). Laboratory abnormalities were evaluated by the disseminated intravascular coagulation (DIC) scoring advocated by the International Society of Thrombosis and Haemostasis (ISTH).

RESULTS

APTT was prolonged and D-dimer and F1+2 increased during the acute phase of NE. AT, PC and PS decreased, and TT was shortened, all implying increased thrombin generation. Acutely F1+2 was 3.4-fold and D-dimer even 24-fold higher compared with the recovery phase (median 726 vs 213 pmol/l, and median 4.8 vs 0.2mg/l, respectively, p<0.001 for both). Platelet count correlated with AT, PC, and PS (r=0.73, r=0.81, and r=0.71, respectively, p<0.001 for all) as well as with fibrinogen (r=0.72, p<0.001). Only five patients fulfilled the ISTH diagnosis of DIC.

CONCLUSIONS

During acute NE thrombocytopenia was associated with decreased natural anticoagulants, shortened thrombin time and enhanced fibrinolysis. Augmented thrombin formation and fibrinolysis characterize this hantavirus infection.

Andes virus recognition of human and Syrian hamster beta3 integrins is determined by an L33P substitution in the PSI domain

Andes virus (ANDV) causes a fatal hantavirus pulmonary syndrome (HPS) in humans and Syrian hamsters. Human alpha(v)beta(3) integrins are receptors for several pathogenic hantaviruses, and the function of alpha(v)beta(3) integrins on endothelial cells suggests a role for alpha(v)beta(3) in hantavirus directed vascular permeability. We determined here that ANDV infection of human endothelial cells or Syrian hamster-derived BHK-21 cells was selectively inhibited by the high-affinity alpha(v)beta(3) integrin ligand vitronectin and by antibodies to alpha(v)beta(3) integrins. Further, antibodies to the beta(3) integrin PSI domain, as well as PSI domain polypeptides derived from human and Syrian hamster beta(3) subunits, but not murine or bovine beta(3), inhibited ANDV infection of both BHK-21 and human endothelial cells. These findings suggest that ANDV interacts with beta(3) subunits through PSI domain residues conserved in both Syrian hamster and human beta(3) integrins. Sequencing the Syrian hamster beta(3) integrin PSI domain revealed eight differences between Syrian hamster and human beta(3) integrins. Analysis of residues within the PSI domains of human, Syrian hamster, murine, and bovine beta(3) integrins identified unique proline substitutions at residues 32 and 33 of murine and bovine PSI domains that could determine ANDV recognition. Mutagenizing the human beta(3) PSI domain to contain the L33P substitution present in bovine beta(3) integrin abolished the ability of the PSI domain to inhibit ANDV infectivity. Conversely, mutagenizing either the bovine PSI domain, P33L, or the murine PSI domain, S32P, to the residue present human beta(3) permitted PSI mutants to inhibit ANDV infection. Similarly, CHO cells transfected with the full-length bovine beta(3) integrin containing the P33L mutation permitted infection by ANDV. These findings indicate that human and Syrian hamster alpha(v)beta(3) integrins are key receptors for ANDV and that specific residues within the beta(3) integrin PSI domain are required for ANDV infection. Since L33P is a naturally occurring human beta(3) polymorphism, these findings further suggest the importance of specific beta(3) integrin residues in hantavirus infection. These findings rationalize determining the role of beta(3) integrins in hantavirus pathogenesis in the Syrian hamster model.