Allele Frequencies of Human Platelet Antigen 1, 2, 3, and 5 Systems in Patients with Chronic Refractory Autoimmune Thrombocytopenia and in Normal Persons

Thude, Hansjörg; Gatzka, Elfriede; Anders, O; Barz, Dagmar

doi:10.1046/j.1423-0410.1999.7730149.x

Cited by 16 publications

(9 citation statements)

References 17 publications

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“…The authors found a higher incidence of the HPA-1a, HPA-3b and HPA-5b alleles in cITP compared to healthy blood donors from the same region, but they found no involvement of HPA-2 in this group of patients. These results differ from data obtained in other studies in which the HPA-1 and HPA-3 systems seem to have no association with ITP in the populations studied, but HPA-2 and HPA-5 were associated 10, 11, 12, 15. The mechanisms that explain these associations are not known yet.…”

contrasting

confidence: 99%

“…HPAs are polymorphisms of platelet surface Gps which result in alloantigen expression, leading to alloimmunization mainly after transfusions and pregnancies 13 . These polymorphisms have heterogeneous distribution in populations with distinct ethnic backgrounds and especially HPA-2 and HPA-5 have been described to be possible risk factors in the development of ITP 10, 11, 14, 15. In this issue, Carmo et al 16 have evaluated the association of HPAs and chronic ITP (cITP) in a small group of patients from the Amazonian region of Brazil, which has a population with a particular HPA distribution compared to the Brazilian population in general 17 .…”

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confidence: 99%

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Human platelet antigens and primary immune thrombocytopenia

Castro

2017

Revista Brasileira de Hematologia e Hemoterapia

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confidence: 99%

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confidence: 99%

Human platelet antigens and primary immune thrombocytopenia

Castro

2017

Revista Brasileira de Hematologia e Hemoterapia

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“…In addition, Castro et al 12 suggested that the presence of HPA-5 b might be associated to increased risk for acute ITP in Brazilian patients. On the other hand, Thude et al 15 showed that allele frequencies of the HPA-1, HPA-3 and HPA-5 were identical between patients with refractory autoimmune thrombocytopenia and blood donors in the German population. While, the HPA-2 b was related to a higher risk for chronic ITP in Macedonian patients 14 .…”

Section: Discussionmentioning

confidence: 99%

“…These polymorphisms can be recognized as alloantigens or autoantigens and trigger the clearance of opsonized platelets by phagocytes in the reticuloendothelial system or inhibition of platelet production 11 . Several groups worldwide have tried to establish a possible association between HPA polymorphisms and ITP 12, 13, 14, 15. Some ITP-specific autoepitopes have been suggested, such as HPA-2a in German patients with chronic refractory ITP 14 and HPA-2b in Macedonian patients with ITP 15 .…”

Section: Introductionmentioning

confidence: 99%

“…Several groups worldwide have tried to establish a possible association between HPA polymorphisms and ITP 12, 13, 14, 15. Some ITP-specific autoepitopes have been suggested, such as HPA-2a in German patients with chronic refractory ITP 14 and HPA-2b in Macedonian patients with ITP 15 . In addition, Castro et al, 12 suggested the presence of HPA-5b in Brazilian patients with increased risk for acute ITP, while the HPA-5a has been implicated in Korean patients 13 .…”

Section: Introductionmentioning

confidence: 99%

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Molecular typing of human platelet antigens in immune thrombocytopenia patients in northern Brazil

Carmo

Klippel

Cordeiro

et al. 2017

Revista Brasileira de Hematologia e Hemoterapia

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BackgroundImmune thrombocytopenia is an immune disease characterized by thrombocytopenia and bleeding due to platelet antibodies against platelet membrane glycoproteins. Human platelet antigens are derived from polymorphisms of these glycoproteins. The aim of this study was to investigate human platelet antigen frequencies in immune thrombocytopenia patients from the state of Amazonas, Brazil and investigate the potential association between specific antigens and risk for immune thrombocytopenia.MethodHuman platelet antigen typing was performed by BeadChip technology to determine allelic variants of 11 systems (HPA-1 to HPA-9, HPA-11 and HPA-15). Thirty-six patients (8 male and 28 female) with a median age of 34 years (range: 9–69 years) were evaluated and compared with data from Amazonas blood donors.ResultsPlatelet counts varied from 3 to 98 × 109/L. The allele frequencies were 0.944 for HPA-1a, 0.056 for HPA-1b, 0.847 for HPA-2a, 0.153 for HPA-2b, 0.555 for HPA-3a, 0.444 for HPA-3b, 0.805 for HPA-5a, 0.222 for HPA-5b, 0.9975 for HPA-9a, 0.025 for HPA-9b, 0.486 for HPA-15a and 0.513 for HPA-15b. Among immune thrombocytopenia individuals, no b allele of the HPA-4, -6, -7, -8 and -11 were found.ConclusionsThe results suggest HPA-1a, HPA-3b and HPA-5b are immune thrombocytopenia-specific autoepitopes.

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Genetic studies in pediatric ITP: outlook, feasibility, and requirements

2010

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The genomic revolution in medicine has not escaped attention of clinicians and scientists involved in medical management and research studies of immune thrombocytopenic purpura (ITP). In principle, ITP biology and care will benefit greatly from modern methods to understand the patterns of gene expression and genetic markers associated with fundamental parameters of the disease including predictors of remission; risk factors for severity; determinants of response to various therapies; and possibly biological sub-types. However, applying modern genetics to ITP carries severe challenges: (i) achieving adequate sample sizes is a fundamental problem because ITP is rare (and in pediatric ITP, chronic cases constitute only about 1/4 of the total); (ii) familial transmission of childhood ITP is so rare that a convincing pedigree requires consideration of other immunologic or hematologic disorders; (iii) ITP is probably biologically heterogeneous, based on clinical observations, immunological studies and animal models. Here we review the advantages and disadvantages of potential genetic approaches. Sufficient information is available to set reasonable bounds on which genetic analyses of ITP are feasible, and how they are most likely to be accomplished. The highest priority is for accurate phenotypes to compare to genetic analyses. Several registries worldwide hold promise for accomplishing this goal.

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Allele Frequencies of Human Platelet Antigen 1, 2, 3, and 5 Systems in Patients with Chronic Refractory Autoimmune Thrombocytopenia and in Normal Persons

Abstract: This study suggests an association between the HPA-2a allele and chronic refractory AITP. The HPA-2a allele may be involved in the formation of an AITP-specific autoepitope.

Cited by 16 publications

References 17 publications

Human platelet antigens and primary immune thrombocytopenia

Human platelet antigens and primary immune thrombocytopenia

Molecular typing of human platelet antigens in immune thrombocytopenia patients in northern Brazil

Genetic studies in pediatric ITP: outlook, feasibility, and requirements

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