Drug-dependent Platelet Antibodies Research Articles

Trastuzumab-Induced Thrombocytopenia Correlated by Drug-Dependent Platelet Antibodies.

Trastuzumab-Induced Thrombocytopenia Correlated by Drug-Dependent Platelet Antibodies.

Drug-Induced Thrombocytopenia following a Transvaginal Oocyte Retrieval for In Vitro Fertilization.

Drug-induced immune thrombocytopenia has been associated with hundreds of medications and can lead to devastating consequences for the patient. We present a case of a healthy 33-year-old female undergoing in vitro fertilization who developed a severe drug-induced thrombocytopenia, petechiae, and a large hemoperitoneum after receiving Cefazolin antibiotic prophylaxis for a transvaginal oocyte retrieval. The patient was admitted to the intensive care unit for resuscitation with blood products. The presence of drug-dependent platelet antibodies to Cefazolin was confirmed serologically.

Approach to the Diagnosis and Management of Drug-Induced Immune Thrombocytopenia

Drug-induced immune thrombocytopenia (DITP) is a challenging clinical problem that is under-recognized, difficult to diagnose and associated with severe bleeding complications. DITP may be caused by classic drug-dependent platelet antibodies (eg, quinine); haptens (eg, penicillin); fiban-dependent antibodies (eg, tirofiban); monoclonal antibodies (eg, abciximab); autoantibody formation (eg, gold); and immune complex formation (eg, heparin). A thorough clinical history is essential in establishing the diagnosis of DITP and should include exposures to prescription medications, herbal preparations and even certain foods and beverages. Clinical and laboratory criteria have been established to determine the likelihood of a drug being the cause of thrombocytopenia, but these criteria can only be applied retrospectively. The most commonly implicated drugs include quinine, quinidine, trimethoprim/sulfamethoxazole and vancomycin. We propose a practical approach to the diagnosis of the patient with suspected DITP. Key features are: the presence of severe thrombocytopenia (platelet nadir <20×10(9)/L); bleeding complications; onset 5 to 10days after first drug exposure, or within hours of subsequent exposures or after first exposure to fibans or abciximab; and exposure to drugs that have been previously implicated in DITP reactions. Treatment involves stopping the drug(s), administering platelet transfusions or other therapies if bleeding is present and counselling on future drug avoidance. The diagnosis can be confirmed by a positive drug re-challenge, which is often impractical, or by demonstrating drug-dependent platelet reactive antibodies in vitro. Current test methods, which are mostly flow cytometry-based, must show drug-dependence, immunoglobulin binding, platelet specificity and ideally should be reproducible across laboratories. Improved standardization and accessibility of laboratory testing should be a focus of future research.

A systematic evaluation of laboratory testing for drug‐induced immune thrombocytopenia

Drug-induced immune thrombocytopenia (DITP) can be confirmed by the demonstration of drug-dependent platelet antibodies in vitro; however, laboratory testing is not readily accessible and test methods are not standardized. To identify drugs with the strongest evidence for causing DITP based on clinical and laboratory criteria. We developed a grading system to evaluate the quality of DITP laboratory testing. The 'DITP criteria' were: (i) Drug (or metabolite) was required for the reaction in vitro; (ii) Immunoglobulin binding was demonstrated; (iii) Two or more laboratories obtained positive results; and (iv) Platelets were the target of immunoglobulin binding. Laboratory diagnosis of DITP was considered definite when all criteria were met and probable when positive results were reported by only one laboratory. Two authors applied the DITP criteria to published reports of each drug identified by systematic review. Discrepancies were independently adjudicated. Of 153 drugs that were clinically implicated in thrombocytopenic reactions, 72 (47%) were associated with positive laboratory testing. Of those, 16 drugs met criteria for a definite laboratory diagnosis of DITP and thus had the highest probability of causing DITP. Definite drugs were: quinine, quinidine, trimethoprim/sulfamethoxazole, vancomycin, penicillin, rifampin, carbamazepine, ceftriaxone, ibuprofen, mirtazapine, oxaliplatin and suramin; the glycoprotein IIbIIIa inhibitors abciximab, tirofiban and eptifibatide; and heparin. We identified drugs with the strongest evidence for an association with immune thrombocytopenia. This list may be helpful for ranking potential causes of thrombocytopenia in a given patient.

The Significance of Anti-Platelet Antibodies Associated with Antibiotic Use, A Descriptive Analysis.

Abstract 4470 IntroductionAntibiotics (Abx) have been implicated in immune thrombocytopenia via drug dependent platelet antibodies (DDPA). Our institution has had a DDPA assay available since 1994 which is used to guide clinical decisions. We performed a retrospective review to determine the significance of DDPA. MethodsWe reviewed the medical records of patients (pts) who tested positive for abx DDPA between 1994 and 2006 and performed a descriptive analysis. Detection of DDPAs was performed using a previously described, modified solid phase red cell adherence assay that detects hapten or immune complex reactions. ResultsA total of 71 pts were included in this analysis. Multiple classes of abx were tested. Platelet nadir was <50 in 70%, between 50 and 100 in 26% and over 100 in 4% of pts. Pts had between 1 and 4 abx tested: 37% had 1, 37% had 2, 15% had 3, and 11% had 4 tested; 65% of pts had one abx positive and 35% had >1 abx positive for DDPA. Of those with >1 abx tested (n=45), 14 (31%) had all tested abx positive. 53% of abx testing took place on or after the abx stop date and 32% of abx tested were administered for <=3 days. Only 29 of 38 pts receiving heparin were tested for heparin-associated antibodies, and 14 had positive results. 49 pts had other non-abx drugs tested, 19 with positive DDPA. Thus, 35% had alternative non-abx testing positive for DDPA. 31% of pts had bleeding complications and 35% of pts died during hospitalization. Excluding pts who died and those with non-abx positive DDPA left 25 pts, median platelet counts were: abx start=142; nadir=22, abx discontinuation=46, hospital discharge=192. ConclusionsAntibiotic DDPA testing is usually performed in ill pts with multiple medical complications and comorbidities. Abx were stopped for concern of DDPA in a number of pts for whom typical immune thrombocytopenia was not present or alternative explanations could be found. Though some pts exhibited improvement in platelet count after abx were stopped, a clear understanding of which pts may benefit from DDPA testing could not be determined based on the retrospective nature of this study and the complexity of pts histories. Further research is necessary to clarify the clinical applicability of DPPA testing. Disclosures:Szczepiorkowski:Cersus Corporation: Research Funding; CaridianBCT: Research Funding; BASF: Research Funding; Terumo Corporation: Research Funding; Fenwel, Inc - Scientific Advisory Board: Research Funding.

Drug-Induced Thrombocytopenia

Drug-induced thrombocytopenia was first described in the 19th century, yet our understanding of its pathogenesis continues to evolve. The list of drugs implicated in drug-induced thrombocytopenia is extensive and growing. Many, if not most, of these medications induce thrombocytopenia by immune mechanisms. Because the degree of thrombocytopenia can put patients at risk for serious bleeding, a prompt diagnosis is key to clinical management. The laboratory approach to diagnosing drug-induced thrombocytopenia is 2-pronged. First, nondrug causes of thrombocytopenia must be ruled out. Second, testing for drug-dependent platelet antibodies, available at specialized reference laboratories, often can identify the offending medication, although usually not in time for initial clinical management. Once a medication is suspected of causing thrombocytopenia, it must be discontinued promptly, and the patient should be monitored closely. Thrombocytopenia generally resolves quickly after offending medication withdrawal, and the prognosis of drug-induced thrombocytopenia is then excellent.

Drug-Induced Thrombocytopenia

Abstract Drug-induced thrombocytopenia was first described in the 19th century, yet our understanding of its pathogenesis continues to evolve. The list of drugs implicated in drug-induced thrombocytopenia is extensive and growing. Many, if not most, of these medications induce thrombocytopenia by immune mechanisms. Because the degree of thrombocytopenia can put patients at risk for serious bleeding, a prompt diagnosis is key to clinical management. The laboratory approach to diagnosing drug-induced thrombocytopenia is 2-pronged. First, nondrug causes of thrombocytopenia must be ruled out. Second, testing for drug-dependent platelet antibodies, available at specialized reference laboratories, often can identify the offending medication, although usually not in time for initial clinical management. Once a medication is suspected of causing thrombocytopenia, it must be discontinued promptly, and the patient should be monitored closely. Thrombocytopenia generally resolves quickly after offending medication withdrawal, and the prognosis of drug-induced thrombocytopenia is then excellent.

Oxaliplatin-Mediated Autoimmune Thrombocytopenia

Drug-induced immune thrombocytopenia (DITP) has been associated with > 100 drugs, including chemotherapeutic agents. Platelet destruction in DITP is caused by immunoglobulins that recognize specific platelet membrane glycoproteins only in the presence of the sensitizing drug.1,2 The diagnosis of DITP is often delayed in patients with cancer who develop thrombocytopenia after the administration of chemotherapeutic agents and is most commonly attributable to myelosuppression by chemotherapy and/or marrow replacement by the tumor. We previously described a case of thrombocytopenia caused by oxaliplatin,3 and in this report, we describe another patient who developed severe thrombocytopenia and bleeding symptoms during treatment of metastatic colon cancer with oxaliplatin. A 57-year-old black woman with stage IV colon cancer was transferred from a local hospital with bleeding from her port in the setting of profound thrombocytopenia. Her past treatments included 6 cycles of systemic 5-fluorouracil (5-FU) and leucovorin per the Mayo Regimen that was subsequently changed to XELOX-B (oxaliplatin; 130 mg/m2 day 1 every 3 weeks, capecitabine 850 mg/m2 orally twice daily × 14 days, bevacizumab 7.5 mg/kg every 3 weeks) because of progressive disease. The patient received her 11 cycles of XELOX-B about 17 hours before the onset of bleeding. The hematologic profile before initiating the eleventh cycle showed the following: white blood cell count: 2.3/mm3 (absolute neutrophil count: 1.8/mm3); hematocrit (HCT): 40%; and platelet count: 89 × 109/L. On presentation, the patient was afebrile and hemodynamically stable. A slow but continuous bleeding was noted at the site of her porta-catheter on the right side of her chest with no local evidence for trauma or infection. Laboratory data demonstrated a platelet count of 17 × 109/L. The patient was transfused with 6 units of platelets and transferred to the university hospital for further management. After transfer, further laboratory work was obtained, which showed platelet count of 27 × 109/L. Disseminated intravascular coagulation (DIC) panel was negative for any abnormality, and HCT dropped to 29%. The patient was observed in the hospital, and her platelet count was checked every 12 hours as shown in Figure 1. Because of concern for oxaliplatin-mediated autoimmune thrombocytopenia, serum was collected on the third day of hospitalization and sent to the Blood Center of Southeastern Wisconsin, Inc. to detect drug-dependent antibodies. Drug-dependent platelet antibodies were detected in patient sera using flow cytometry as previously described.4-6 In brief, normal group O platelets were incubated with test serum in the presence and absence of drug and were washed twice in buffer containing drug at the same concentration as in the primary incubation mixture. Platelet-associated immunoglobulins were then detected by flow cytometry using fluorescein isothiocyanate (FITC)–tagged anti-human immunoglobulin (Ig) G (Fcγ-specific) and phycoerythrin (PE)-tagged anti-human IgM, (Fcμ-specific). Sera from normal, healthy donors and sera containing previously identified quinine-dependent platelet antibodies served as negative and positive controls, respectively. In selected studies, platelets were “coated” with oxaliplatin by incubating washed normal platelets with the drug at various concentrations followed by 5 washes in 1.5-mL volumes of acid citrate dextrose (ACD)/phosphate-buffered saline (PBS)/bovine serum albumin (BSA) to remove unbound drug. A positive reaction was defined as mean platelet fluorescence intensity (MFI) at least twice that of platelets processed identically except for the absence of drug. Reactions of this strength always exceeded

Investigating the possibility of drug-dependent platelet antibodies

Investigating the possibility of drug-dependent platelet antibodies

Detection of drug-dependent, platelet-reactive antibodies by solid-phase red cell adherence assays.

We developed a simple modification of the solid-phase red cell adherence (SPRCA) assay system that can be used to identify drug-dependent platelet antibodies (DDPAs) reactive by either the hapten or immune complex reaction mechanisms. Between January 1994 and August 1996 we tested sera from 173 patients [123 (71%) with unexplained thrombocytopenia and 50 (29%) because of poor responses to platelet transfusions not explicable by alloimmunization or the clinical situation] for DDPAs possibly associated with the receipt of 61 different drugs. We correlated positive results with patients' clinical courses. DDPAs were identified in samples from 138 (80%) of the patients tested. Antibodies reactive only by the hapten mechanism were identified in 51 (37%) of those sera exhibiting positive reactions. The clinical courses of 108 (78%) patients were evaluable. Discontinuation of the implicated drug(s) resulted in prompt (<5 d) resolution of the thrombocytopenia or improvement in response to transfusion in all of these patients. In four cases thrombocytopenia returned upon re-exposure to the implicated drug. This adaptation of SPRCA provides a simple means of investigating the possibility of DDPAs and documents a higher frequency of these antibodies than has previously been suspected.

Thrombocytopenia Induced by Vancomycin-Dependent Platelet Antibody

Background and objectives: Many drugs are associated with thrombocytopenic purpura through immune-mediated platelet destruction. The case of a woman who suffered lifethreatening thrombocytopenia during vancomycin treatment for Staphylococcus aureus septicemia is reported. Materials and methods: Conventional clinical and laboratory methods, including flow cytometry. Results: After treatment of septicemia with vancomycin, severe thrombocytopenia and bleeding occurred, without detection of drug-dependent platelet antibodies (DDPA). This was followed by vegetative endocarditis, whereupon antibiotics were withdrawn so as to isolate the organism. The thrombocytopenia was corrected. On day 34, antibiotics including vancomycin were reinstituted, and three days later thrombocytopenia recurred. With a change in antibiotics, the platelet count corrected itself within four days. Conclusions: Vancomycin may induce potentially severe immunological thrombocytopenia.

Detection of drug-dependent platelet antibodies by use of solid-phase red cell adherence techniques

Abstract Many drugs have been reported to cause drug-dependent thrombocytopenia, either by the immune complex or by hapten mechanisms. Testing for the presence of these platelet antibodies has not been considered feasible for transfusion services because their presence was thought to be rare, and their detection involved complex and costly methods. We have developed a new technique for detection of these antibodies that can be performed without the need for specialized and expensive instrumentation. A solid-phase red cell adherence assay was used to detect drug-dependent platelet antibodies active by either the immune complex or the hapten mechanism. Three cases were evaluated for the presence of drug-dependent platelet antibodies. Two patients presented with thrombocytopenia that could not be attributed to other causes. The third case was evaluated for the presence of drug-dependent antibodies after poor responses to platelet transfusions. In these three cases, discontinuation of the implicated drugs, i.e., porcine heparin, quinine sulfate, amoxicillin, BactrimTM, and albuterol, was followed by a correction of thrombocytopenia or improved platelet transfusion response within 72 hours. This test methodology and protocol has proven very useful in avoiding transfusions with little likelihood of benefit, and in identifying drugs interfering with platelet recovery or survival. Further investigations with this technique may expand our knowledge of the capability of this technique and of the observed frequency of drug-related immunologic platelet destruction. Immunohematology 1995;11:143–149.

Quinidine-induced thrombocytopenic purpura: clinical presentation in relation to drug-dependent and drug-independent platelet antibodies.

We have studied the clinical course of quinidine-induced thrombocytopenia in relation to the presence of drug-dependent (dd-ab:s) and drug-independent antibodies in 14 patients. Thrombocytopenia was reversible in 9 d after discontinuation of quinidine treatment in 10 patients. In four it lasted more than 1 month. Drug-dependent antibodies of IgG class were detectable in seven patients: in six by an immunofluorescence test applying flow cytometry and in one patient by a monoclonal antibody-immobilized platelet protein assay (MAIPA) only. The dd-ab:s of this patient had glycoprotein (GP) IIb/IIIa specificity. Five of the six patients with dd-ab:s by immunofluorescence test had GPIb/IX-specific dd-ab:s by MAIPA. They recovered within 5 d after discontinuation of the drug. All four patients with prolonged thrombocytopenia had elevated platelet-associated IgG (PAIgG) in the acute phase as studied by a direct platelet immunofluorescence test. The remaining five patients displayed a relatively rapid clinical recovery but less uniform pattern of immunological findings. The results suggest that patients with GPIb/IX-specific dd-ab:s recover promptly despite an acute and profound thrombocytopenia. Another sub-group with prolonged thrombocytopenia had persistently elevated PAIgG during the convalescent phase.

Detection of drug‐dependent platelet antibodies using immobilized Staphylococcal protein A

Serum samples from eight patients suspected of having drug-induced immunologic thrombocytopenia provoked by a variety of medications were tested for drug-dependent platelet antibodies with a newly developed assay that forms rosettes of antibody-coated platelets around Staphylococcal protein A-Sepharose beads. The same samples were then tested with immunofluorescence and 51Cr-release assays. Seven of eight patients (87.5%) tested positive for drug-dependent antibodies by the rosette assay. In contrast, two of eight (25.0%) and one of eight (12.5%) patients tested positive for drug-dependent antibodies by immunofluorescence and 51Cr release, respectively. These results demonstrate that the new rosette method is significantly more sensitive and specific for the detection of drug-dependent platelet antibodies than either immunofluorescence or 51Cr release.

Detection of drug-dependent IgG antibodies with antiplatelet activity by the antiglobulin consumption assay.

Drug-induced thrombocytopenia is a common acquired hemorrhagic disorder. In this study 32 patients with drug-induced thrombocytopenia were examined with the antiglobulin consumption assay. Platelet-associated IgG was elevated in 19 of 20 patients that were analyzed. An increase in serum platelet bindable IgG was observed in 24 subjects after the addition of various drugs (acetylsalicylic acid, noraminopyrine, antibiotics, sulfamides, digoxin, heparin and chenodeoxycholic acid). These findings are significant for the presence of drug-dependent platelet antibodies.

AET-Treated Platelets: Their Usefulness for Platelet Antibody Detection and an Examination of Their Altered Sensitivity to Immune Lysis

Abstract2-Aminoethylisothiouronium bromide (AET) increases the sensitivity of blood cells to complement-mediated immune lysis. We compared the sensitivities of untreated or AET-treated platelets to immune lysis induced by different types of platelet antibody in the 51Cr platelet lysis test. AET platelets were 8–16 times more sensitive to autoantibody and alloantibody, but 8–16 times less sensitive to drug- dependent antibody. AET-platelets bound similar amounts of alloantibody but less drug-dependent antibody, and they lysed at higher complement dilutions than did untreated platelets. AET-platelets detected 10 of 25 autoantibodies, 9 of 9 alloantibodies, and 5 of 8 drug-dependent antibodies. Untreated platelets detected 1 of 25, 6 of 9, and 7 of 8 of these respective platelet antibodies. The use of AET-platelets in the 51Cr platelet lysis test increases its sensitivity for detecting non- drug-dependent platelet antibodies. AET-platelets resemble paroxysmal nocturnal hemoglobinuria (PNH) platelets in their enhanced sensitivity to complement-mediated lysis. They differ from PNH platelets in their insensitivity to immune lysis induced by drug-dependent antibodies and, in this respect, are similar to Bernard-Soulier syndrome platelets.

AET-treated platelets: their usefulness for platelet antibody detection and an examination of their altered sensitivity to immune lysis

2-Aminoethylisothiouronium bromide (AET) increases the sensitivity of blood cells to complement-mediated immune lysis. We compared the sensitivities of untreated or AET-treated platelets to immune lysis induced by different types of platelet antibody in the 51Cr platelet lysis test. AET platelets were 8–16 times more sensitive to autoantibody and alloantibody, but 8–16 times less sensitive to drug- dependent antibody. AET-platelets bound similar amounts of alloantibody but less drug-dependent antibody, and they lysed at higher complement dilutions than did untreated platelets. AET-platelets detected 10 of 25 autoantibodies, 9 of 9 alloantibodies, and 5 of 8 drug-dependent antibodies. Untreated platelets detected 1 of 25, 6 of 9, and 7 of 8 of these respective platelet antibodies. The use of AET-platelets in the 51Cr platelet lysis test increases its sensitivity for detecting non- drug-dependent platelet antibodies. AET-platelets resemble paroxysmal nocturnal hemoglobinuria (PNH) platelets in their enhanced sensitivity to complement-mediated lysis. They differ from PNH platelets in their insensitivity to immune lysis induced by drug-dependent antibodies and, in this respect, are similar to Bernard-Soulier syndrome platelets.

A Simple Immunofluorescence Test for the Detection of Platelet Antibodies

Immunofluorescence tests on platelets have always been hampered by nonspecific fluorescence caused by non-immunological binding of plasma proteins to the platelet membrane. It was found that this could be easily overcome by fixation of the cells with paraformaldehyde (PFA). By using PFA-fixed platelets, a simple method for the detection of platelet antibodies, the platelet suspension immunofluorescence test (PSIFT) was developed. PFA fixation did not alter or inactivate the platelet antigens tested. Platelet-reactive antibodies detected specifically with the PSIFT included platelet-specific agglutinins of the IgM class, non-agglutinating platelet-specific antibodies of the IgG class, drug-dependent platelet antibodies, HLA antibodies, as well as anti-A and anti-B antibodies. The sensitivity of the new test was satisfactory, as was its reproducibility. Measurement of platelet immunofluorescence was possible in a continuous flow microfluorometer, making a principle, quantitation of platelet antibodies and antigens possible.