Laboratory investigation of immune thrombocytopenia.

Warner, Margaret; Kelton, John G.

doi:10.1136/jcp.50.1.5

Cited by 41 publications

(30 citation statements)

References 68 publications

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“…Restriction endonuclease sites and linker sequence were introduced during a second PCR step, followed by overlapping extension PCR joining the VL and VH fragments. The final 2.4G2 scFv construct had the arrangement VL-(G 4 S) 3 -VH ( Table 1).…”

Section: Cloning and Construction Of Fusion Protein Constructsmentioning

confidence: 99%

“…The 3G8 scFv-MSA construct consists of the huFcgRIIIA-binding domain [3G8 scFv in the arrangement of VL-(G 4 S) 4 -VH] fused to HSA (Uniprot P02768) via a hexa-glycine linker. The 2.4G2 scFv-MSA construct consists of the murine FcgRIII/IIB-binding domain [2.4G2 scFv in the arrangement of VL-(G 4 S) 3 -VH] fused to mouse serum albumin (MSA) (Uniprot P07724) via a hexa-glycine linker. Genes containing nucleotide sequences of the 3G8 scFv-HSA or the 2.4G2 scFv-MSA fusion construct were synthesized by GeneArt.…”

Section: Cloning and Construction Of Fusion Protein Constructsmentioning

confidence: 99%

“…[1][2][3][4][5] Antibody-mediated platelet destruction in the majority of ITP patients involves Fc-mediated phagocytosis by macrophages via the Fcg receptors (FcgRs). [2][3][4] One of the major activatory FcgRs implicated in platelet depletion is the FcgRIIIA, also a therapeutic target. 6 The first FcgRIIIA-specific monoclonal antibody (mAb) 3G8 was described in 1982 7 and was later investigated clinically in ITP patients.…”

Section: Introductionmentioning

confidence: 99%

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Monovalent Fc receptor blockade by an anti–Fcγ receptor/albumin fusion protein ameliorates murine ITP with abrogated toxicity

Menard

Prechl

et al. 2016

Blood

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Section: Cloning and Construction Of Fusion Protein Constructsmentioning

confidence: 99%

Section: Cloning and Construction Of Fusion Protein Constructsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Monovalent Fc receptor blockade by an anti–Fcγ receptor/albumin fusion protein ameliorates murine ITP with abrogated toxicity

Menard

Prechl

et al. 2016

Blood

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“…Recently, some investigators have suggested that techniques capable of measuring immunoglobulins bound to individual platelet glycoproteins can be used to investigate ITP patients. These assays are termed phase III assays and include the immunoblot, immunoprecipitation and assays which target specific platelet proteins (Warner & Kelton, 1997;Woods et al, 1984). Since specific protein assays use the enzyme-linked immunosorbent (EIA) techniques which are simple, fast, and do not require radioactive isotopes, they are now being investigated for their usefulness as diagnostic tools.…”

mentioning

confidence: 99%

A prospective study of protein‐specific assays used to investigate idiopathic thrombocytopenic purpura

et al. 1999

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Summary. Idiopathic thrombocytopenic purpura (ITP) is a disorder in which platelets, sensitized by autoantibodies, are destroyed by the reticuloendothelial system. The diagnosis of ITP has been a clinical one because assays measuring platelet-associated IgG (PAIgG) have low specificity. The recently introduced assays that measure antibodies against specific platelet glycoproteins (GP) offer the possibility of improved specificity. In this report we describe two prospective studies. In the first study we compared two proteinspecific assays (AC and MAIPA) looking for the presence of autoantibodies against GP IIb/IIIa in 81 patient samples. These results were compared with an immunoradiometric assay for PAIgG. The second study investigated the enhanced sensitivity of measuring anti-GP Ib/IX autoantibodies in 76 patient samples. The protein-specific assays were able to differentiate immune from non-immune thrombocytopenia (specificity 91%, sensitivity 39%), whereas the PAIgG assay could not (specificity 19%, sensitivity 78%). The addition of the Ib/IX AC assay maintained a specificity of 92% while increasing the diagnostic sensitivity to 66%. In contrast to the PAIgG assay, there was no correlation between the platelet count and the likelihood or degree of positivity within the control samples using the glycoprotein assays. These studies confirm that glycoprotein assays can be used as diagnostic tests for ITP.

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“…They involved incubating test serum with control platelets and measuring a platelet activation-dependent endpoint, such as platelet aggregation or release of platelet granule contents. These assays were abandoned because they lacked both sensitivity and specificity [4].…”

Section: Introductionmentioning

confidence: 99%

Prospective evaluation of a new platelet glycoprotein (GP)-specific assay (PakAuto) in the diagnosis of autoimmune thrombocytopenia (AITP)

et al. 2005

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Assays measuring platelet-associated immunoglobulin G (PAIgG), while highly sensitive, lack specificity in diagnosing autoimmune thrombocytopenia (AITP). We prospectively evaluated a new commercially available glycoprotein (GP)-specific assay, the PakAuto (GTI, Brookfield, WI), for its clinical usefulness in distinguishing immune from nonimmune thrombocytopenia (TP), in 216 patients with autoimmune TP (both primary ''idiopathic'' and ''secondary'') and 46 patients with TP due to other causes. This assay is designed to detect both platelet-associated (direct assay) and plasma (indirect assay) antiplatelet antibodies specific for GPs IIb/IIIa, Ib/IX, and Ia/IIa. The mean platelet counts of the immune (79 ± 7 · 10 9 /L) and nonimmune groups (78 ± 7 · 10 9 /L), were similar (P = 0.95). The direct assay was positive in 114/216 patients with AITP (53%), and 13/46 with nonimmune TP (28%). Among the AITP group, the majority (61%) of patients with positive test results had autoantibodies reactive against all three GP targets. The sensitivity, specificity, positive, and negative predictive values for the direct PakAuto were 53%, 72%, 90%, and 24%, respectively, comparable to previously published experience of GP-specific assays. However, in some cases of TP due to nonimmune cause, the PakAuto was highly specific. Only 3 of 22 patients with gestational and 1 of 8 with familial/congenital TP had a positive direct assay, indicating that the test may be particularly useful for excluding an immune etiology for TP in certain patient subgroups. Am.

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Laboratory investigation of immune thrombocytopenia.

Cited by 41 publications

References 68 publications

Monovalent Fc receptor blockade by an anti–Fcγ receptor/albumin fusion protein ameliorates murine ITP with abrogated toxicity

Monovalent Fc receptor blockade by an anti–Fcγ receptor/albumin fusion protein ameliorates murine ITP with abrogated toxicity

A prospective study of protein‐specific assays used to investigate idiopathic thrombocytopenic purpura

Prospective evaluation of a new platelet glycoprotein (GP)-specific assay (PakAuto) in the diagnosis of autoimmune thrombocytopenia (AITP)

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