Glanzmann's thrombasthenia classification
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Glanzmann's thrombasthenia |
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Differentiating Glanzmann's thrombasthenia from other Diseases |
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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]
Overview
Glycoprotein (GP)IIb-IIIa(aIIb,P3) is a Ca2+- G dependent heterodimer complex that belongs to the integrin family receptors involved in cell-cell and cell matrix adhesion. Normal platelets contain approximately 50,000 molecules of GPIIb-IIIa, which comprise 1% to 2% of the total platelet protein.[1] The two genes, encoding for GPIIb (ITGA2B) and GPIIIa (ITGB3) are closely associated at chromosome 17q21.[2]
Classification
Inherent GT
Glanzmann thrombasthenia (GT) is an autosomal recessive inherited qualitative platelet disorder characterized by absence or reduction of platelet glycoprotein GPIIb or GPIIIa. On the basic of levels of GPIIb/ IIIa as detected by CD61, GT has been subclassified into three groups based on the platelet fibrinogen content and clot retraction into types I, II, and III. Patients with less than 5% of normal GPIIb/IIIa are classified as type I and patients with 5% to 20% normal GPIIb/IIIa are type II. Type III variants usually have dysfunctional receptors with near-normal GPIIb/ IIIa levels.[3] Variability exists in the subtypes found in various ethnic groups. Type I GT is relatively frequent in Iraqi-Jews and Arabs residing in Israel, whereas type II GT is more often found in the Japanese population.[4]
Variant GTs are defined as patients with the clinical phenotype of GT but whose platelets express αIIbβ3 (>20%) in amounts that would normally support platelet aggregation. variants are characterized by the inability of stimulated platelets to bind soluble Fg or antibodies recognizing activation-dependent determinants on αIIbβ3. They are mostly given by single amino acid substitutions with the nature and position of the affected residue defining the residual functional response. As for the alloantigen systems carried by αIIbβ3, most variant forms concern ITGB3.
Acquired GT
Acquired GT is commonly the result of an autoantibody attack on platelet αIIbβ3, or iso antibodies inhibiting proper function. The production of autoantibodies has been associated with platelet transfusions, as well as numerous hematologic conditions, including immune thrombocytopenic purpura, non-Hodgkin’s lymphoma, multiple myeloma, myelodysplastic syndrome, hairy cell leukemia, and acute lymphoblastic leukemia. In a case report done by Blickstein et al, a patient with systemic lupus erythematosus presented in adulthood with degrees of mucocutaneous bleeding secondary to antibody production against GPIIb/IIIa.5 Also, some anti-thrombotic therapies use αIIbβ3 antagonists, such as abciximab, eptifibatide, and tirofiban, for treatment of acute coronary events, which can trigger a transient GT-like state.[5]
References
- ↑ Kato A, Yamamoto K, Aoki N (1992). "Classification of Glanzmann's thrombasthenia based on the intracellular transport pathway of GPIIb-IIIa". Thromb Haemost. 68 (5): 615–6. PMID 1455408.
- ↑ Manne RK, Natarajan K, Patil R, Prathi VS, Beeraka SS, Kolaparthi VS (2014). "Glanzmann thrombasthenia associated with human immunodeficiency virus-positive patient". Int J Prev Med. 5 (4): 500–4. PMC 4018600. PMID 24829739.
- ↑ Arimura H (1975). "Correlation between molecular size and interferon- inducing activity of poly I:C". Acta Virol. 19 (6): 457–66. PMID 1990;75:1383–95 Check
|pmid=value (help). - ↑ Kannan M, Ahmed RP, Jain P, Kumar R, Choudhry VP, Saxena R (2003). "Type I Glanzmann thrombasthenia: most common subtypes in North Indians". Am J Hematol. 74 (2): 139–41. doi:10.1002/ajh.10395. PMID 14508803.
- ↑ Arimura H (1975). "Correlation between molecular size and interferon- inducing activity of poly I:C". Acta Virol. 19 (6): 457–66. PMID 1990;75:1383–95 Check
|pmid=value (help).