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Journal ArticleDOI

Fab-mediated binding of drug-dependent antibodies to platelets in quinidine- and quinine-induced thrombocytopenia.

01 Jan 1985-Journal of Clinical Investigation (American Society for Clinical Investigation)-Vol. 75, Iss: 1, pp 310-314

TL;DR: Findings suggest that binding of drug-induced antibodies to platelets occurs at the Fab domains of the IgG molecule.

AbstractPlatelets coated with quinine- or quinidine-induced antibodies form rosettes around protein A-Sepharose beads and normal platelets form rosettes about protein A-Sepharose beads coated with these antibodies. These reactions occurred only in the presence of sensitizing drug. Platelets also formed rosettes about protein A-Sepharose beads coated with an anti-PIA1 antibody, but drug was not required. Formation of rosettes between antibody-coated platelets and protein A-Sepharose was inhibited by F(ab')2 fragments of goat antibody specific for the Fc portion of human IgG, while rosette formation between antibody-coated protein A-Sepharose and platelets was inhibited by F(ab')2 fragments directed against the F(ab')2 portion of the IgG molecule. Since binding of IgG to protein A is known to occur via the Fc region, these findings suggest that binding of drug-induced antibodies to platelets occurs at the Fab domains of the IgG molecule.

Topics: Protein G (60%), Fragment crystallizable region (56%), Protein A (56%), Immunoglobulin Fc Fragments (52%), Platelet (50%)

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Citations
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Journal ArticleDOI
TL;DR: The current understanding of pathogenesis is summarized and a guide for diagnosis and management of thrombocytopenia is provided.
Abstract: Drug-induced thrombocytopenia should be suspected in any patient with acute thrombocytopenia of unknown cause Although the incidence is low, more than 100 drugs have been implicated in thrombocytopenia, including quinine, sulfonamides, abciximab, carbamazepine, and vancomycin, as well as herbal remedies and several nonprescription drugs This review summarizes the current understanding of pathogenesis and provides a guide for diagnosis and management of this potentially dangerous disorder

419 citations


Journal ArticleDOI
TL;DR: The most important aspects of patient management are a high index of suspicion and a careful history of drug exposure in an individual who presents with acute, often severe thrombocytopenia of unknown etiology.
Abstract: Drug-induced immune thrombocytopenia (DITP) can be triggered by a wide range of medications. Although many cases of DITP are mild, some are characterized by life-threatening bleeding symptoms. The pathogenesis of DITP is complex, in that at least six different mechanisms have been proposed by which drug-induced antibodies can promote platelet destruction. It is possible in many cases to identify antibodies that react with platelets in the presence of the sensitizing drug, but the required testing is technically demanding and not widely available. Therefore, a decision on whether to discontinue an implicated medication in a patient suspected of having DITP must be made on clinical grounds. An algorithm is available that can be helpful in assessing the likelihood that a particular drug caused thrombocytopenia, but the most important aspects of patient management are a high index of suspicion and a careful history of drug exposure in an individual who presents with acute, often severe thrombocytopenia of unknown etiology. How drugs induce platelet-reactive antibodies and how, once formed, the antibodies cause platelet destruction following exposure to the drug is poorly understood. Further studies to address these issues and characterize more completely the range of drugs and drug metabolites that can cause DITP are needed.

250 citations



Journal ArticleDOI
01 Jul 1996-Blood
TL;DR: The experience suggests that MAIPA assays are useful in the laboratory assessment of thrombocytopenia, should be performed before therapy, and that some patients with 'nonimmune' thromBocy topenia may have genuine antiplatelet antibodies.
Abstract: The diagnosis of idiopathic immune thrombocytopenia remains a clinical diagnosis based on the exclusion of other causes of immune and nonimmune thrombocytopenia. Measurement of platelet-associated Ig (PAIg), while sensitive, is nonspecific for the diagnosis of immune thrombocytopenia. Published experience of antigen capture assays (including monoclonal antibody immobilization of platelet antigens or MAIPA) suggest a high sensitivity and specificity (70% to 80%) in selected groups of patients. In a prospective evaluation of 158 patients with thrombocytopenia from all causes, we report a sensitivity of 51% and specificity of 80% for direct MAIPA assays. MAIPA was considerably better in discriminating immune from nonimmune thrombocytopenia than two assays of PAIgG. Antiplatelet antibodies detected by MAIPA were more frequently directed against the glycoprotein (GP) IIb/IIIa than the GP Ib/IX complex. Our experience suggests that MAIPA assays are useful in the laboratory assessment of thrombocytopenia, should be performed before therapy, and that some patients with 'nonimmune' thrombocytopenia may have genuine antiplatelet antibodies.

178 citations


Journal ArticleDOI
TL;DR: The most common drugs to cause DIIHA are anti-microbials, which are associated with drug-dependent antibodies, and the most common drug to cause AIHA is fludarabine.
Abstract: Drug-induced immune hemolytic anemia (DIIHA) is rare; it can be mild or associated with acute severe hemolytic anemia (HA) and death. About 125 drugs have been implicated as the cause. The HA can be caused by drug-independent antibodies that are indistinguishable, in vitro and in vivo, from autoantibodies causing idiopathic warm type autoimmune hemolytic anemia (AIHA). More commonly, the antibodies are drug-dependent (i.e., will only react in vitro in the presence of the drug). The most common drugs to cause DIIHA are anti-microbials (e.g., cefotetan, ceftriaxone and piperacillin), which are associated with drug-dependent antibodies. The most common drug to cause AIHA is fludarabine. Finding out which drug is causing the problem and stopping that drug is the first approach to therapy. It is not easy to identify the drug interactions accurately in vitro; laboratories specializing in this area can be of great help.

154 citations


Cites background from "Fab-mediated binding of drug-depend..."

  • ...In 1985, Aster's group showed that antibodies from patients with quinine and quinidine-induced thrombocytopenia bound to the platelets by their Fab portion, not their Fc portion, of the Ig molecule.(36) This did not support the “nonspecific” adsorption of drug–anti-drug complexes as suggested by Shulman, and even later suggestions that the attachment was to the Fc receptor on platelets....

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References
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Journal ArticleDOI
TL;DR: It is concluded that, in PNH, platelets and granulocytes share the membrane defect characteristic of erythrocytes in this disorder, and these observations support the concept that PNH arises as the result of a somatic mutation in a primitive cell capable of differentiating into ery Throttleblast, myeloblast, and megakaryoblast lines.
Abstract: The tendency of platelets and leukocytes to lyse after their interaction with antibody and complement was studied by measuring the release of 51Cr from cells labeled with this isotope. Platelets from six patients with paroxysmal nocturnal hemoglobinuria (PNH) were 15-230 times more sensitive to antibodies and 10-32 times more sensitive to complement than normal platelets or platelets from patients with other types of thrombocytopenic or hemolytic disorders. Mixed white blood cell (WBC) preparations from patients with PNH were 3-20 times more sensitive to anti-WBC antibodies and 5-10 times more sensitive to C′ than were WBC preparations from normal subjects, but PNH lymphocytes showed normal immunologic reactivity. PNH platelets, like PNH erythrocytes, lysed more readily than normal platelets in acidified serum and in media of reduced ionic strength, but these characteristics were not demonstrable with PNH WBC's under the conditions of study. In PNH, platelets appear to comprise a single population with respect to their sensitivity to immune lysis, yet their survival time as measured with 51Cr falls within normal limits. PNH granulocytes likewise appear to consist of a single, uniformly sensitive population. It is concluded that, in PNH, platelets and granulocytes share the membrane defect characteristic of erythrocytes in this disorder. These observations support the concept that PNH arises as the result of a somatic mutation in a primitive cell capable of differentiating into erythroblast, myeloblast, and megakaryoblast lines. PNH platelets or enzymatically treated normal platelets permit the detection of some types of platelet antibodies in dilutions up to 2000-fold greater than is possible with currently available methods, a finding suggesting that the immune lysis technique will prove useful for the study of platelet immunology.

198 citations


"Fab-mediated binding of drug-depend..." refers methods in this paper

  • ...6 mMEDTA) by differential centrifugation as previously described (7)....

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Journal ArticleDOI
TL;DR: Purpura occurring during convalescence can best be explained on the assumption of an allergic basis, similar perhaps to that to which nephritis following streptococcal infections has been attributed.
Abstract: 1.1. Purpura is due to a vascular lesion. Thrombocytopenia, when present, tends to increase the haemorrhagic tendency. 2.2. Platelets and capillary endothelium are antigenically related. An antibody which injures the platelets can also damage the capillary endothelium. Thrombocytopenia and capillary endothelial damage may, therefore, have a common cause. 3.3. Allergic purpura is of two types: (1) Purpura associated with an erythematous skin lesion, and also with joint and visceral symptoms: the Henoch-Schonlein syndrome. This syndrome is generally regarded as a manifestation of allergy but, apart from a very small proportion of cases which are undoubtedly due to hypersensitivity to foods, the cause of the syndrome is unknown and its allergic basis is entirely unproved. (2) True purpura in which the surrounding skin is normal. It may be due to an abnormal reaction to an infection or to a drug or, occasionally, to some other substance but is rarely if ever due to foods. Many infections and drugs can cause, in different individuals, both thrombocytopenic and athrombocytopenic purpura. 4.4. Cases of true purpura due to infections may be divided into those which occur at the height of an infection and those which occur during convalescence. The former type appears to be due to an abnormal susceptibility of the patient's tissues to the factors which normally cause thrombocytopenia and increased capillary fragility at the height of an infection. If this abnormal susceptibility is shown only by the vascular endothelium, athrombocytopenic purpura will result. If the megakaryocytes and platelets are also affected, the purpura will be thrombocytopenic. Purpura occurring during convalescence can best be explained on the assumption of an allergic basis, similar perhaps to that to which nephritis following streptococcal infections has been attributed. 5.5. The only example of purpura due to a drug which has been subjected to experimental analysis is thrombocytopenic purpura due to sedormid (allyl-isopropyl-acetyl-carbamide). Sedormid appears to act by combining with platelets, so conferring upon them the properties of a weak antigen. This antigen is formed whenever the drug is taken but it has the power of stimulating antibody formation in only a very small proportion of those taking the drug. Thrombocytopenia occurs only in those who develop the antibody and is due to lysis of the platelet-sedormid antigen by antibody and complement. The capillary lesion is probably produced in a similar way, the drug combining with the endothelial cells to form a further antigen which then reacts with the antibody which causes platelet lysis, this reaction producing the vascular lesion which plays such an important part in the development of purpura. It is not known how far these findings are applicable to purpura due to other drugs. An isolated observation on thrombocytopenic purpura due to quinine suggests that the mechanisms underlying sedormid purpura may be similar to those underlying thrombocytopenic purpura due to other drugs. In athrombocytopenic purpura due to drugs it is suggested that only the capillary endothelium combines with the drug to form an antigen, and therefore that it alone reacts with the antibody, this reaction causing the capillary lesion.

184 citations


"Fab-mediated binding of drug-depend..." refers background in this paper

  • ...Ackroyd (13) proposed a mechanism for the drug-ddAbplatelet reaction in which drug, acting as a hapten, modified a platelet constituent to produce a hapten-carrier complex which induces antibody formation....

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Journal ArticleDOI
TL;DR: Results of this study were consistent with the possibilities that the protein moiety of a haptenic antigen involved in development of an antibody which attaches to a cell is not necessarily a component of the cell, and that the cell reacts with the antibody by virtue of having a surface favorable for non-specific adsorption of certain haptene-antibody complexes.
Abstract: A steric and kinetic model for the sequence and mechanism of reactions leading to formation of a complex from an antibody, a haptene (quinidine), and a cell membrane (platelets), and to fixation of complement by the complex was deduced from the effects of varying the initial concentration of each component of the complex on the amount of complement fixed, from kinetic aspects of the sequential reactions, and from other chemical and physical properties of the various components involved. Theoretical results calculated using equations based on the model, which were derived by Dr. Terrell L. Hill, were similar in all respects to experimental results. Results of this study were consistent with the possibilities that the protein moiety of a haptenic antigen involved in development of an antibody which attaches to a cell is not necessarily a component of the cell, and that the cell reacts with the antibody by virtue of having a surface favorable for non-specific adsorption of certain haptene-antibody complexes.

153 citations


"Fab-mediated binding of drug-depend..." refers background in this paper

  • ...Drugs like quinidine and quinine bind weakly to platelets in the absence of ddAb (2, 3); excess soluble drug is required for maximum ddAb binding to platelets (3); and excess soluble drug fails to displace platelet-bound ddAb (2, 3), but it is not yet certain whether ddAb interact with platelets via the Fab or the Fc portion of the antibody molecule....

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  • ...Shulman (2) provided experimental support for the latter hypothesis by showing that quinidine binds only weakly to platelets and would, therefore, be unlikely to form complexes capable of inducing antibody, and that high concentrations of drug do not displace plateletbound ddAb, as would be expected in a conventional hapten inhibition reaction....

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Journal ArticleDOI
TL;DR: It is demonstrated that incorporation of cholesterol into platelet membranes is associated with a diminished inhibitory effect of prostaglandin E, on platelet aggregation and therefore adenosine 3’:5’-monophosphate production in these platelets.
Abstract: The incorporation of cholesterol into human platelets by means of incubation with cholesterol-rich lecithin dispersions is associated with a decreased fluidity in the phospholipid hydrocarbon core of platelet membranes and an increased sensitivity of platelets to aggregating agents. We examined whether the platelet membrane enzyme, adenylate cyclase is influenced by changes in phospholipid fluidity. After incubation for 5 h at 37” with cholesterol-rich lecithin dispersions, platelets demonstrated a 55% increase in membrane cholesterol content associated with a 5to lo-fold decrease in the sensitivity of these platelets to the aggregation inhibitor and stimulator of adenylate cyclase, prostaglandin E,. However, these platelets were normally sensitive to direct inhibition of epinephrine-induced aggregation by dibutyryl adenosine 3’:5’-monophosphate. Platelet cholesterol content increased in platelets during incubation with cholesterol-rich lecithin dispersions, associated with a parallel increase in both platelet adenosine 3’:5’-monophosphate content and the basal activity of adenylate cyclase. At 5 h, platelet cyclic AMP levels had increased 56% and basal adenylate cyclase activity had increased 2.5-fold. In contrast, platelets incubated with pure lecithin dispersions lost 21% cholesterol and their basal cyclase activity decreased 40%. The adenylate cyclase of control platelets was stimulated 3.5-fold by prostaglandin E, (1.0 PM) and 4.5-fold by sodium fluoride (1.0 mM). In contrast, the adenylate cyclase of cholesterol-rich platelets was stimulated neither by prostaglandin E, nor by sodium fluoride. Adenylate cyclase in cholesterol-depleted platelets was stimulated normally by prostaglandin E,. The kinetic constants of adenosine 3’:5’-monophosphate phosphodiesterases (EC 3.1.4.17) of cholesterol-rich platelets were normal. These studies demonstrate that incorporation of cholesterol into platelet membranes is associated with a diminished inhibitory effect of prostaglandin E, on platelet aggregation. This appears to be related to the inability of prostaglandin E, to stimulate adenylate cyclase and therefore adenosine 3’:5’-monophosphate production in these platelets. The loss of hormone and fluoride responsiveness as well as the increased basal activity of adenylate cyclase in cholesterol-rich platelets may be due to the physical effects of cholesterol on platelet membrane phospholipid.

125 citations


"Fab-mediated binding of drug-depend..." refers background in this paper

  • ...It is unlikely that this apparent platelet-platelet binding was due to aggregation, since it occurred in the presence of 8 mMEDTA and, in some experiments, 20 ng/ ml PGEI, which is a potent inhibitor of aggregation (10)....

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Journal ArticleDOI
TL;DR: It is demonstrated that in quinine- and quinidine-induced thrombocytopenia, drug and antibody combine first in the soluble phase to form a complex, which then binds with high affinity to a receptor on the platelet surface (innocent bystander reaction), and that these antibodies are heterogeneous in respect to the amount of drug required to promote their binding to platelets, the number of platelet receptors they recognize, and their binding affinities.
Abstract: Binding of quinine- and quinidine-dependent antibodies to platelets was studied using an electroimmunoassay to measure platelet-bound IgG. Antibodies from four patients with drug-induced thrombocytopenia differed significantly in their interaction with platelets: association constants for binding to platelets at high drug concentrations ranged from 0.29 to 2.6 x 10(7) M(-1), the maximum number of antibody molecules bound ranged from 36,000 to 161,000/platelet, the amount of drug necessary to achieve half-maximum binding of antibodies to platelets ranged from 2 to 60 muM, and only one of the antibodies cross-reacted with the stereoisomer of the drug to which the patient was sensitized. Binding of the antibodies to platelets was enhanced at the highest achievable molar ratio of drug:antibody, 10,000:1, rather than being inhibited, as would be expected in a conventional, hapten-dependent reaction. The drug-antibody-platelet reaction was unaffected by Factor VIII/von Willebrand protein, nonspecifically aggregated IgG, or heat-labile complement components. After pretreatment with tritiated quinine, platelets retained several hundred thousand molecules of drug each, but failed to bind detectable amounts of antibody. However, platelets treated simultaneously with quinine-dependent antibody and tritiated quinine retained significantly more drug after repeated washes than platelets treated with drug and normal serum. These findings support the proposition that in quinine- and quinidine-induced thrombocytopenia, drug and antibody combine first in the soluble phase to form a complex, which then binds with high affinity to a receptor on the platelet surface (innocent bystander reaction), and demonstrate that these antibodies are heterogeneous in respect to the amount of drug required to promote their binding to platelets, the number of platelet receptors they recognize, and their binding affinities.

65 citations


"Fab-mediated binding of drug-depend..." refers background or methods in this paper

  • ...These observations seem most consistent with the following model for drug-ddAb-platelet binding: platelets coated with drug express an unstable neoantigen which is stabilized upon interaction with the Fab domains of ddAb (3)....

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  • ...Drugs like quinidine and quinine bind weakly to platelets in the absence of ddAb (2, 3); excess soluble drug is required for maximum ddAb binding to platelets (3); and excess soluble drug fails to displace platelet-bound ddAb (2, 3), but it is not yet certain whether ddAb interact with platelets via the Fab or the Fc portion of the antibody molecule....

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  • ...Weconfirmed and extended these observations by showing that even platelets coated with a million molecules of drug do not express ddAb binding sites unless excess soluble drug is present (3)....

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  • ...That is, platelets pretreated with drug and then washed do not express binding sites for ddAb, and bound ddAb can readily be removed from platelets by washing in the absence of drug (3)....

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  • ...Mixtures were then centrifuged at 12,800 g for 2 min, and supernatants were analyzed for IgG content by electroimmunoassay (3)....

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