Aplastic Anemia and Idiopathic Thrombocytopenic Purpura with Antibody to Platelet Glycoprotein llb/llla Following Resection of Malignant Thymoma

Abstract The characteristic decreased recovery and survival of transfused platelets in nonalloimmunized patients with idiopathic thrombocytopenic purpura (ITP) suggest that plasma antiplatelet autoantibodies (autoAbs) are present in almost all cases. Studies emphasizing reactions of IgG autoAbs with platelet glycoprotein (GP) IIb/IIIa indicate that less than 50% of ITP patients have detectable serum Abs, and that many of these Abs may not be pathogenic because they are directed against epitopes in the cytoplasmic domain of GPIIIa (Fujisawa et al, Blood 77:2207, 1991 and 79:1441, 1992). We evaluated the contribution of Ig classes other than IgG to the overall incidence of serum Abs in 47 patients with chronic ITP and the frequency of reactions with GPs IIb/IIIa, Ib/IX, IV, and Ia/IIa. Abs were further characterized by their reactions with cytosolic or exosolic GP epitopes and their titers and apparent affinities. Using immunobead techniques we found (1) anti- GPs in 85% of sera; (2) IgA and IgG Abs each in 68%, together in 51%; (3) IgM agglutinins in 15%, always with another Ab class; (4) GP Ib/IX, IIb/IIIa, IV, and Ia/IIa targets in 83%, 81%, 38%, and 28% of cases, respectively; (5) 93% of positive sera reactive with more than one GP; but GP IV or Ia/IIa never the sole target; (6) Abs against cytosolic epitopes on one or more of GPs IIIa, Ib alpha, and IIb beta in 66% of sera, always accompanied by Abs against exosolic epitopes of the same or a different GP; (7) autoAbs against cytosolic GP epitopes in 38% of 16 patients recovered from posttransfusion purpura and drug purpura; and (8) evidence that serum ITP Abs, often high-titered, saturate platelets less than alloAbs against the same GPs. Whereas Abs against external GP epitopes are a distinctive marker for ITP in 80% of patients, Abs against internal GP epitopes are likely a secondary phenomenon of platelet destruction and not pathogenic. Anti-GPs against exosolic epitopes were also found in eluates of patients platelets', suggesting that they have pathogenic significance.

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Extracellular epitopes of platelet glycoprotein Ib alpha reactive with serum antibodies from patients with chronic idiopathic thrombocytopenic purpura

Blood ◽

10.1182/blood.v86.10.3789.bloodjournal86103789 ◽

1995 ◽

Vol 86 (10) ◽

pp. 3789-3796 ◽

Cited By ~ 29

Author(s):

R He ◽

DM Reid ◽

CE Jones ◽

NR Shulman

Keyword(s):

Escherichia Coli ◽

Idiopathic Thrombocytopenic Purpura ◽

Fusion Proteins ◽

Synthetic Peptides ◽

Immunoaffinity Chromatography ◽

Platelet Glycoprotein ◽

Chronic Idiopathic Thrombocytopenic Purpura ◽

Protein Fragment ◽

Thrombocytopenic Purpura ◽

Insight Into

Glycoproteins (GPs) IIb/IIIa and Ib/IX are principal targets of autoantibodies (autoAbs) in idiopathic thrombocytopenic purpura (ITP). Platelet-associated Abs against GPIIb/IIIa primarily recognize discontinuous or nonlinear epitopes (Fujisawa et al, Blood 81:1284, 1993). This study focused on whether Abs against the extracellular domain of GPIb/IX might react with short linear amino acid (aa) sequences of GPIb alpha. Complementary DNAs (cDNAs) coding for two overlapping fragments of GPIb alpha were amplified, cloned into pFLAG.2 plasmids, and expressed in Escherichia coli DH5 alpha competent cells as FLAG fusion proteins, which were purified by anti-FLAG immunoaffinity chromatography. Of 16 selected ITP sera containing anti- GPIb/IX, 6 reacted in microtiter radioimmunoassays (RIAs) with recombinant protein fragment 2 (aas 240 to 485); 1 also with fragment 1 (aas 1 to 247). When synthetic peptides corresponding to 4 segments of fragment 2 with high antigenic indices (P1 to P4) were used as targets in RIAs, all 6 sera reacted with P2 (aas 326 to 346); 1 also reacted with P4 (aas 389 to 412). P2 was shown to be present on the surface of intact platelets by adsorption studies, and anti-P2 was detected in direct eluates of platelets from ITP patients. Glycocalicin in solution effectively competed with immobilized P2 for anti-P2; P2 in solution was a less effective competitor. Epitope scanning with a panel of synthetic 15-mer peptides localized the P2 epitope to the sequence, TKEQTTFPP. Epitope definition may offer insight into the pathophysiology of and more specific treatments for ITP.

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Cell-Based Immunotherapy with Different Subsets of Tolerogenic Dendritic Cell in Idiopathic Thrombocytopenic Purpura.

Blood ◽

10.1182/blood.v112.11.3408.3408 ◽

2008 ◽

Vol 112 (11) ◽

pp. 3408-3408

Author(s):

Xiao-Lin Zhang ◽

Jun Peng ◽

Shu-Qian Xu ◽

Xin-Guang Liu ◽

Yuan Yu ◽

...

Keyword(s):

T Cells ◽

Regulatory T Cells ◽

Idiopathic Thrombocytopenic Purpura ◽

Peripheral Tolerance ◽

Platelet Glycoprotein ◽

Autoantibody Production ◽

Autoreactive T Cells ◽

Thrombocytopenic Purpura ◽

Autoreactive T Cell ◽

Tolerogenic Dcs

Abstract There is growing evidence that tolerogenic dendritic cells (DCs) play an important role in maintaining peripheral tolerance through the induction of anergic or regulatory T cells. However, in humans, little is known about the ability of tolerogenic DCs to induce tolerance to autoantigens in autoimmune patients. Idiopathic thrombocytopenic purpura (ITP) is an immune-mediated disease in which platelets are destroyed by antiplatelet autoantibodies. Here, we explored in vitro the ability of four subsets of tolerogenic DCs (i.e., immature DCs (imDCs), IL-10-modulated DCs (IL-10-DCs), vasoactive intestinal peptide-modulated DCs (VIP-DCs) or plasmacytoid DCs (pDCs)) derived from patients with ITP, to induce an anergic state or regulatory T cells in autologous platelet glycoprotein (GP)-specific T cells. GPIIb/IIIa-reactive T cells were preincubated with GPIIb/IIIa-loaded imDCs, IL- 10-DCs, pDCs or VIP-DCs, and then rechallenged with autologous mature DCs (mDCs) in the presence of GPIIb/IIIa. Only when T cells were cultured with GPIIb/IIIa-loaded VIP-DCs in primary incubation, inhibited proliferation of GPIIb/IIIa-reactive T cells could be observed at rechallenge with GPIIb/IIIa-loaded mDCs. The anergic state of VIPDC- primed GPIIb/IIIa-reactive T cells could be reversed when rechallenged with GPIIb/ IIIa-loaded mDCs in the presence of a high concentration of exogenous IL-2. Meanwhile, GPIIb/IIIa-reactive T cells were also cultured with VIP-DCs loaded with tetanus toxoid (TT). In contrast to T cells pretreated with GPIIb/IIIa-loaded VIP-DCs, GPIIb/IIIareactive T cells pretreated with TT-loaded VIP-DCs proliferated when rechallenged with GPIIb/IIIa-loaded mDCs, which demonstrated that the induced anergy of autoreactive T cells is antigen specific. Additionally, functional analysis showed that VIP-DC-modulated T cells could not suppress the proliferation of newly induced GPIIb/IIIa-reactive T cells when cocultured with GPIIb/IIIa-loaded mDCs. These results indicated that VIP-DCs could induce autoreactive T cells anergic but not functionally suppressive. Moreover, we found that coculture of VIP-DCs with autologous PBMCs resulted in reduced production of anti-GPIIb/IIIa antibodies, suggesting that GPIIb/IIIa-reactive T cells lost their helper function for inducing autoantibody production by B cells. In contrast, reduced antibody production could not be found when autologous PBMCs were cocultured with imDCs, IL-10-DCs or pDCs. In conclusion, our studies revealed the therapeutic potential of VIPDCs, compared with imDCs, IL-10-DCs or pDCs, to induce autoreactive T-cell anergy to GP antigens, which would in turn facilitate the reestablishment of autoantigen-specific tolerance in patients with ITP.

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Characterization of human megakaryocyte colony-stimulating factor in the urinary extracts from patients with aplastic anemia and idiopathic thrombocytopenic purpura

Blood ◽

10.1182/blood.v61.3.556.556 ◽

1983 ◽

Vol 61 (3) ◽

pp. 556-560 ◽

Cited By ~ 22

Author(s):

M Kawakita ◽

M Ogawa ◽

E Goldwasser ◽

T Miyake

Keyword(s):

Aplastic Anemia ◽

Idiopathic Thrombocytopenic Purpura ◽

Colony Formation ◽

Specific Activity ◽

Elution Profile ◽

Colony Stimulating Factor ◽

Thrombocytopenic Purpura ◽

Phenol Treatment ◽

Stimulating Factor

Abstract Using procedures that were effective in the purification of human urinary erythropoietin (Epo), we attempted initial purification of megakaryocyte colony-stimulating factors (CSF) in urinary extracts from patients with aplastic anemia (AA) and idiopathic thrombocytopenic purpura (ITP). Comparison of colony stimulation by purified human Epo and crude urinary extracts revealed: (1) that the pure Epo augments megakaryocyte colony formation in culture and (2) MEG-CSF activity is also present in materials other than Epo in the crude urinary extracts from the two types of patients. Similar to purification of Epo, ethanol precipitation and sulfopropyl-Sephadex chromatography provided twofold and threefold increases in the specific activity of MEG-CSF, respectively. In contrast to Epo, however, significant inactivation of MEG-CSF activity was seen with phenol treatment. The elution profile of MEG-CSF seen on hydroxylapatite chromatography of urinary extracts was different from that of Epo. These data provided a basis for initial steps for purification of MEG-CSF and support the notion that MEG-CSF is distinct from Epo.

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Concentrations of Thrombopoietin in Bone Marrow in Normal Subjects and in Patients With Idiopathic Thrombocytopenic Purpura, Aplastic Anemia, and Essential Thrombocythemia Correlate With Its mRNA Expression of Bone Marrow Stromal Cells

Blood ◽

10.1182/blood.v92.1.46.413k44_46_52 ◽

1998 ◽

Vol 92 (1) ◽

pp. 46-52 ◽

Cited By ~ 70

Author(s):

Yasuo Hirayama ◽

Sumio Sakamaki ◽

Takuya Matsunaga ◽

Takashi Kuga ◽

Hiroyuki Kuroda ◽

...

Keyword(s):

Bone Marrow ◽

Aplastic Anemia ◽

Idiopathic Thrombocytopenic Purpura ◽

Essential Thrombocythemia ◽

Stromal Cells ◽

Detection System ◽

Normal Subjects ◽

Normal Range ◽

Thrombocytopenic Purpura ◽

Polymerase Chain

The function of bone marrow (BM) stromal thrombopoietin (TPO) in megakaryopoiesis remains unknown. In the present study we attempted to clarify the pathophysiological implications of stromal TPO in normal subjects (NS) and in patients with idiopathic thrombocytopenic purpura (ITP), aplastic anemia (AA), and essential thrombocythemia (ET) by measuring TPO concentrations in BM and peripheral blood (PB) and by estimating the levels of stromal TPO mRNA with TaqMan fluorescence-based post–reverse transcription-polymerase chain reaction product detection system. The results showed that TPO concentrations in PB were significantly elevated in patients with ITP (34.9 ± 11.7 pg/mL) and AA (364.1 ± 153.5 pg/mL) but within normal range in patients with ET (each 20.0 and 22.1; NS, 22.1 ± 8.2 pg/mL). In all subjects, the TPO concentrations in BM correlated well with the PB levels, and the former were consistently higher than the latter. The concentrations of TPO in BM also correlated with the levels of TPO mRNA in stromal cells. Furthermore, expression levels of TPO mRNA clearly correlated with megakaryocyte counts in NS and patients with ITP, indicating that stromal TPO actually enhances megakaryopoiesis. Thus, our results in the present study indicate that TPO from BM stromal cells is considered to play an essential role for megakaryopoiesis under various patho-physiological conditions.

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Fibrinogen/Fibrin Degradation Products in Serum of Patients with Idiopathic Thrombocytopenic Purpura: Elevated Levels during Severe Thrombocytopenic Phase of the Disease

Thrombosis and Haemostasis ◽

10.1055/s-0038-1647961 ◽

1976 ◽

Vol 35 (03) ◽

pp. 628-634

Author(s):

Toshiro Nagasawa ◽

Ichiro Kono ◽

Tetsushi Sakurai ◽

Heihachiro Kashiwagi

Keyword(s):

Aplastic Anemia ◽

Idiopathic Thrombocytopenic Purpura ◽

Degradation Products ◽

Treated Group ◽

Severe Thrombocytopenia ◽

Thrombocytopenic Purpura ◽

Fibrin Degradation Products ◽

Essentially Normal ◽

Euglobulin Lysis Time ◽

Healthy Control

SummarySera from 23 patients with idiopathic thrombocytopenic purpura (ITP), 14 patients with aplastic anemia with severe thrombocytopenia and healthy control subj ects were tested for the presence of fibrinogen/fibrin degradation products (FDP), using the tanned red cell hemagglutination inhibition immunoassay. The concentrations of circulating FDP of ITP patients (mean 12.01 μg/ml) were significantly higher than those of the patients with aplastic anemia (mean 4.01 μg/ml, p <0.05) or normal controls (mean 3.10 μg/ml, p <0.001). The patients with untreated ITP with very low platelet counts had higher levels of FDP than those of the treated group (p < 0.01). Serum FDP and a battery of other coagulation-fibrinolysis tests were serially carried out over a period of 10 weeks in two patients with ITP. The initially high FDP promptly decreased as circulating platelets increased in response to steroid in both patients, while plasma fibrinogen, euglobulin lysis time, prothrombin time and partial thromboplastin time remained essentially normal during the course of observation. The exact source of the increased serum FDP in ITP was not extablished, but a few possible mechanisms responsible for this abnormality were discussed.

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